Re: [syzbot] [net?] [mm?] INFO: rcu detected stall in inet_rtm

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* Re: [syzbot] [net?] [mm?] INFO: rcu detected stall in inet_rtm_newaddr (2)
       [not found] <681a1770.050a0220.a19a9.000d.GAE@google.com>
@ 2025-10-11  7:41 ` syzbot
  2025-10-11  9:42   ` Eric Dumazet
  0 siblings, 1 reply; 10+ messages in thread
From: syzbot @ 2025-10-11  7:41 UTC (permalink / raw)
  To: davem, dsahern, edumazet, hdanton, horms, kuba, linux-kernel,
	linux-mm, netdev, pabeni, syzkaller-bugs, tglx

syzbot has found a reproducer for the following issue on:

HEAD commit:    18a7e218cfcd Merge tag 'net-6.18-rc1' of git://git.kernel...
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=12504dcd980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=61ab7fa743df0ec1
dashboard link: https://syzkaller.appspot.com/bug?extid=51cd74c5dfeafd65e488
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14d2a542580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=142149e2580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7a01e6dce97e/disk-18a7e218.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5e1b7e41427f/vmlinux-18a7e218.xz
kernel image: https://storage.googleapis.com/syzbot-assets/69b558601209/bzImage-18a7e218.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+51cd74c5dfeafd65e488@syzkaller.appspotmail.com

sched: DL replenish lagged too much
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (2 GPs behind) idle=7754/1/0x4000000000000000 softirq=15464/15465 fqs=1
rcu: 	(detected by 1, t=10502 jiffies, g=11321, q=371 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5948 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:rb_insert_color_cached include/linux/rbtree.h:113 [inline]
RIP: 0010:rb_add_cached include/linux/rbtree.h:183 [inline]
RIP: 0010:timerqueue_add+0x1a8/0x200 lib/timerqueue.c:40
Code: e7 31 f6 e8 6a 0c de f6 42 80 3c 2b 00 74 08 4c 89 f7 e8 7b 0a de f6 4d 89 26 4d 8d 7e 08 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 <74> 08 4c 89 ff e8 5e 0a de f6 4d 89 27 4d 85 e4 40 0f 95 c5 eb 07
RSP: 0018:ffffc90000007cf0 EFLAGS: 00000046
RAX: 1ffff110170c4f83 RBX: 1ffff110170c4f82 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88805de72358
RBP: 0000000000000000 R08: ffff88805de72357 R09: 0000000000000000
R10: ffff88805de72340 R11: ffffed100bbce46b R12: ffff88805de72340
R13: dffffc0000000000 R14: ffff8880b8627c10 R15: ffff8880b8627c18
FS:  000055557c657500(0000) GS:ffff888125d0f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000600 CR3: 000000002ee76000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 __run_hrtimer kernel/time/hrtimer.c:1794 [inline]
 __hrtimer_run_queues+0x656/0xc60 kernel/time/hrtimer.c:1841
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
 __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1058
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:pv_vcpu_is_preempted arch/x86/include/asm/paravirt.h:579 [inline]
RIP: 0010:vcpu_is_preempted arch/x86/include/asm/qspinlock.h:63 [inline]
RIP: 0010:owner_on_cpu include/linux/sched.h:2282 [inline]
RIP: 0010:mutex_spin_on_owner+0x189/0x360 kernel/locking/mutex.c:361
Code: b6 04 30 84 c0 0f 85 59 01 00 00 48 8b 44 24 08 8b 18 48 8b 44 24 48 42 80 3c 30 00 74 0c 48 c7 c7 90 8c fa 8d e8 a7 cd 88 00 <48> 83 3d ff 27 5e 0c 00 0f 84 b9 01 00 00 48 89 df e8 41 e0 d5 ff
RSP: 0018:ffffc900034c7428 EFLAGS: 00000246
RAX: 1ffffffff1bf5192 RBX: 0000000000000001 RCX: ffffffff819c6588
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8f4df8a0
RBP: 1ffffffff1e9bf14 R08: ffffffff8f4df8a7 R09: 1ffffffff1e9bf14
R10: dffffc0000000000 R11: fffffbfff1e9bf15 R12: ffffffff8f4df8a0
R13: ffffffff8f4df8f0 R14: dffffc0000000000 R15: ffff8880267a9e40
 mutex_optimistic_spin kernel/locking/mutex.c:464 [inline]
 __mutex_lock_common kernel/locking/mutex.c:602 [inline]
 __mutex_lock+0x311/0x1350 kernel/locking/mutex.c:760
 rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978
 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6954
 netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2552
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:742
 __sys_sendto+0x3bd/0x520 net/socket.c:2244
 __do_sys_sendto net/socket.c:2251 [inline]
 __se_sys_sendto net/socket.c:2247 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2247
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7faade790d5c
Code: 2a 5f 02 00 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 70 5f 02 00 48 8b
RSP: 002b:00007ffdd2e3b670 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007faadf514620 RCX: 00007faade790d5c
RDX: 0000000000000028 RSI: 00007faadf514670 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffdd2e3b6c4 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007faadf514670 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10499 jiffies! g11321 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=4286
rcu: rcu_preempt kthread starved for 10500 jiffies! g11321 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:I stack:27224 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7026
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.


^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [syzbot] [net?] [mm?] INFO: rcu detected stall in inet_rtm_newaddr (2)
  2025-10-11  7:41 ` [syzbot] [net?] [mm?] INFO: rcu detected stall in inet_rtm_newaddr (2) syzbot
@ 2025-10-11  9:42   ` Eric Dumazet
  2025-10-12 15:46     ` Jamal Hadi Salim
  0 siblings, 1 reply; 10+ messages in thread
From: Eric Dumazet @ 2025-10-11  9:42 UTC (permalink / raw)
  To: syzbot, Vinicius Costa Gomes, Jamal Hadi Salim
  Cc: davem, dsahern, hdanton, horms, kuba, linux-kernel, linux-mm,
	netdev, pabeni, syzkaller-bugs, tglx

On Sat, Oct 11, 2025 at 12:41 AM syzbot
<syzbot+51cd74c5dfeafd65e488@syzkaller.appspotmail.com> wrote:
>
> syzbot has found a reproducer for the following issue on:
>
> HEAD commit:    18a7e218cfcd Merge tag 'net-6.18-rc1' of git://git.kernel...
> git tree:       net-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=12504dcd980000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=61ab7fa743df0ec1
> dashboard link: https://syzkaller.appspot.com/bug?extid=51cd74c5dfeafd65e488
> compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14d2a542580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=142149e2580000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/7a01e6dce97e/disk-18a7e218.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/5e1b7e41427f/vmlinux-18a7e218.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/69b558601209/bzImage-18a7e218.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+51cd74c5dfeafd65e488@syzkaller.appspotmail.com
>
> sched: DL replenish lagged too much
> rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
> rcu:    0-...!: (2 GPs behind) idle=7754/1/0x4000000000000000 softirq=15464/15465 fqs=1
> rcu:    (detected by 1, t=10502 jiffies, g=11321, q=371 ncpus=2)
> Sending NMI from CPU 1 to CPUs 0:
> NMI backtrace for cpu 0
> CPU: 0 UID: 0 PID: 5948 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
> RIP: 0010:rb_insert_color_cached include/linux/rbtree.h:113 [inline]
> RIP: 0010:rb_add_cached include/linux/rbtree.h:183 [inline]
> RIP: 0010:timerqueue_add+0x1a8/0x200 lib/timerqueue.c:40
> Code: e7 31 f6 e8 6a 0c de f6 42 80 3c 2b 00 74 08 4c 89 f7 e8 7b 0a de f6 4d 89 26 4d 8d 7e 08 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 <74> 08 4c 89 ff e8 5e 0a de f6 4d 89 27 4d 85 e4 40 0f 95 c5 eb 07
> RSP: 0018:ffffc90000007cf0 EFLAGS: 00000046
> RAX: 1ffff110170c4f83 RBX: 1ffff110170c4f82 RCX: 0000000000000000
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88805de72358
> RBP: 0000000000000000 R08: ffff88805de72357 R09: 0000000000000000
> R10: ffff88805de72340 R11: ffffed100bbce46b R12: ffff88805de72340
> R13: dffffc0000000000 R14: ffff8880b8627c10 R15: ffff8880b8627c18
> FS:  000055557c657500(0000) GS:ffff888125d0f000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000200000000600 CR3: 000000002ee76000 CR4: 00000000003526f0
> Call Trace:
>  <IRQ>
>  __run_hrtimer kernel/time/hrtimer.c:1794 [inline]
>  __hrtimer_run_queues+0x656/0xc60 kernel/time/hrtimer.c:1841
>  hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
>  local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
>  __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1058
>  instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
>  sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052
>  </IRQ>
>  <TASK>
>  asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
> RIP: 0010:pv_vcpu_is_preempted arch/x86/include/asm/paravirt.h:579 [inline]
> RIP: 0010:vcpu_is_preempted arch/x86/include/asm/qspinlock.h:63 [inline]
> RIP: 0010:owner_on_cpu include/linux/sched.h:2282 [inline]
> RIP: 0010:mutex_spin_on_owner+0x189/0x360 kernel/locking/mutex.c:361
> Code: b6 04 30 84 c0 0f 85 59 01 00 00 48 8b 44 24 08 8b 18 48 8b 44 24 48 42 80 3c 30 00 74 0c 48 c7 c7 90 8c fa 8d e8 a7 cd 88 00 <48> 83 3d ff 27 5e 0c 00 0f 84 b9 01 00 00 48 89 df e8 41 e0 d5 ff
> RSP: 0018:ffffc900034c7428 EFLAGS: 00000246
> RAX: 1ffffffff1bf5192 RBX: 0000000000000001 RCX: ffffffff819c6588
> RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8f4df8a0
> RBP: 1ffffffff1e9bf14 R08: ffffffff8f4df8a7 R09: 1ffffffff1e9bf14
> R10: dffffc0000000000 R11: fffffbfff1e9bf15 R12: ffffffff8f4df8a0
> R13: ffffffff8f4df8f0 R14: dffffc0000000000 R15: ffff8880267a9e40
>  mutex_optimistic_spin kernel/locking/mutex.c:464 [inline]
>  __mutex_lock_common kernel/locking/mutex.c:602 [inline]
>  __mutex_lock+0x311/0x1350 kernel/locking/mutex.c:760
>  rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
>  inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978
>  rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6954
>  netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2552
>  netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
>  netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346
>  netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
>  sock_sendmsg_nosec net/socket.c:727 [inline]
>  __sock_sendmsg+0x21c/0x270 net/socket.c:742
>  __sys_sendto+0x3bd/0x520 net/socket.c:2244
>  __do_sys_sendto net/socket.c:2251 [inline]
>  __se_sys_sendto net/socket.c:2247 [inline]
>  __x64_sys_sendto+0xde/0x100 net/socket.c:2247
>  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
>  do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7faade790d5c
> Code: 2a 5f 02 00 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 70 5f 02 00 48 8b
> RSP: 002b:00007ffdd2e3b670 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
> RAX: ffffffffffffffda RBX: 00007faadf514620 RCX: 00007faade790d5c
> RDX: 0000000000000028 RSI: 00007faadf514670 RDI: 0000000000000003
> RBP: 0000000000000000 R08: 00007ffdd2e3b6c4 R09: 000000000000000c
> R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
> R13: 0000000000000000 R14: 00007faadf514670 R15: 0000000000000000
>  </TASK>
> rcu: rcu_preempt kthread timer wakeup didn't happen for 10499 jiffies! g11321 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
> rcu:    Possible timer handling issue on cpu=0 timer-softirq=4286
> rcu: rcu_preempt kthread starved for 10500 jiffies! g11321 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
> rcu:    Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
> rcu: RCU grace-period kthread stack dump:
> task:rcu_preempt     state:I stack:27224 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
> Call Trace:
>  <TASK>
>  context_switch kernel/sched/core.c:5325 [inline]
>  __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
>  __schedule_loop kernel/sched/core.c:7011 [inline]
>  schedule+0x165/0x360 kernel/sched/core.c:7026
>  schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
>  rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
>  rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
>  kthread+0x711/0x8a0 kernel/kthread.c:463
>  ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
>  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
>  </TASK>
>
>
> ---
> If you want syzbot to run the reproducer, reply with:
> #syz test: git://repo/address.git branch-or-commit-hash
> If you attach or paste a git patch, syzbot will apply it before testing.

Yet another taprio report.

If taprio can not be fixed, perhaps we should remove it from the
kernel, or clearly marked as broken.
(Then ask syzbot to no longer include it)


^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [syzbot] [net?] [mm?] INFO: rcu detected stall in inet_rtm_newaddr (2)
  2025-10-11  9:42   ` Eric Dumazet
@ 2025-10-12 15:46     ` Jamal Hadi Salim
  2025-10-12 15:52       ` Jamal Hadi Salim
  2025-10-13 21:51       ` Vinicius Costa Gomes
  0 siblings, 2 replies; 10+ messages in thread
From: Jamal Hadi Salim @ 2025-10-12 15:46 UTC (permalink / raw)
  To: Eric Dumazet
  Cc: syzbot, Vinicius Costa Gomes, davem, dsahern, hdanton, horms,
	kuba, linux-kernel, linux-mm, netdev, pabeni, syzkaller-bugs,
	tglx

On Sat, Oct 11, 2025 at 5:42 AM Eric Dumazet <edumazet@google.com> wrote:
>
> On Sat, Oct 11, 2025 at 12:41 AM syzbot
> <syzbot+51cd74c5dfeafd65e488@syzkaller.appspotmail.com> wrote:
> >
> > syzbot has found a reproducer for the following issue on:
> >
> > HEAD commit:    18a7e218cfcd Merge tag 'net-6.18-rc1' of git://git.kernel...
> > git tree:       net-next
> > console output: https://syzkaller.appspot.com/x/log.txt?x=12504dcd980000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=61ab7fa743df0ec1
> > dashboard link: https://syzkaller.appspot.com/bug?extid=51cd74c5dfeafd65e488
> > compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14d2a542580000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=142149e2580000
> >
> > Downloadable assets:
> > disk image: https://storage.googleapis.com/syzbot-assets/7a01e6dce97e/disk-18a7e218.raw.xz
> > vmlinux: https://storage.googleapis.com/syzbot-assets/5e1b7e41427f/vmlinux-18a7e218.xz
> > kernel image: https://storage.googleapis.com/syzbot-assets/69b558601209/bzImage-18a7e218.xz
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+51cd74c5dfeafd65e488@syzkaller.appspotmail.com
> >
> > sched: DL replenish lagged too much
> > rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
> > rcu:    0-...!: (2 GPs behind) idle=7754/1/0x4000000000000000 softirq=15464/15465 fqs=1
> > rcu:    (detected by 1, t=10502 jiffies, g=11321, q=371 ncpus=2)
> > Sending NMI from CPU 1 to CPUs 0:
> > NMI backtrace for cpu 0
> > CPU: 0 UID: 0 PID: 5948 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
> > RIP: 0010:rb_insert_color_cached include/linux/rbtree.h:113 [inline]
> > RIP: 0010:rb_add_cached include/linux/rbtree.h:183 [inline]
> > RIP: 0010:timerqueue_add+0x1a8/0x200 lib/timerqueue.c:40
> > Code: e7 31 f6 e8 6a 0c de f6 42 80 3c 2b 00 74 08 4c 89 f7 e8 7b 0a de f6 4d 89 26 4d 8d 7e 08 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 <74> 08 4c 89 ff e8 5e 0a de f6 4d 89 27 4d 85 e4 40 0f 95 c5 eb 07
> > RSP: 0018:ffffc90000007cf0 EFLAGS: 00000046
> > RAX: 1ffff110170c4f83 RBX: 1ffff110170c4f82 RCX: 0000000000000000
> > RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88805de72358
> > RBP: 0000000000000000 R08: ffff88805de72357 R09: 0000000000000000
> > R10: ffff88805de72340 R11: ffffed100bbce46b R12: ffff88805de72340
> > R13: dffffc0000000000 R14: ffff8880b8627c10 R15: ffff8880b8627c18
> > FS:  000055557c657500(0000) GS:ffff888125d0f000(0000) knlGS:0000000000000000
> > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 0000200000000600 CR3: 000000002ee76000 CR4: 00000000003526f0
> > Call Trace:
> >  <IRQ>
> >  __run_hrtimer kernel/time/hrtimer.c:1794 [inline]
> >  __hrtimer_run_queues+0x656/0xc60 kernel/time/hrtimer.c:1841
> >  hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
> >  local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
> >  __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1058
> >  instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
> >  sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052
> >  </IRQ>
> >  <TASK>
> >  asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
> > RIP: 0010:pv_vcpu_is_preempted arch/x86/include/asm/paravirt.h:579 [inline]
> > RIP: 0010:vcpu_is_preempted arch/x86/include/asm/qspinlock.h:63 [inline]
> > RIP: 0010:owner_on_cpu include/linux/sched.h:2282 [inline]
> > RIP: 0010:mutex_spin_on_owner+0x189/0x360 kernel/locking/mutex.c:361
> > Code: b6 04 30 84 c0 0f 85 59 01 00 00 48 8b 44 24 08 8b 18 48 8b 44 24 48 42 80 3c 30 00 74 0c 48 c7 c7 90 8c fa 8d e8 a7 cd 88 00 <48> 83 3d ff 27 5e 0c 00 0f 84 b9 01 00 00 48 89 df e8 41 e0 d5 ff
> > RSP: 0018:ffffc900034c7428 EFLAGS: 00000246
> > RAX: 1ffffffff1bf5192 RBX: 0000000000000001 RCX: ffffffff819c6588
> > RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8f4df8a0
> > RBP: 1ffffffff1e9bf14 R08: ffffffff8f4df8a7 R09: 1ffffffff1e9bf14
> > R10: dffffc0000000000 R11: fffffbfff1e9bf15 R12: ffffffff8f4df8a0
> > R13: ffffffff8f4df8f0 R14: dffffc0000000000 R15: ffff8880267a9e40
> >  mutex_optimistic_spin kernel/locking/mutex.c:464 [inline]
> >  __mutex_lock_common kernel/locking/mutex.c:602 [inline]
> >  __mutex_lock+0x311/0x1350 kernel/locking/mutex.c:760
> >  rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
> >  inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978
> >  rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6954
> >  netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2552
> >  netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
> >  netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346
> >  netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
> >  sock_sendmsg_nosec net/socket.c:727 [inline]
> >  __sock_sendmsg+0x21c/0x270 net/socket.c:742
> >  __sys_sendto+0x3bd/0x520 net/socket.c:2244
> >  __do_sys_sendto net/socket.c:2251 [inline]
> >  __se_sys_sendto net/socket.c:2247 [inline]
> >  __x64_sys_sendto+0xde/0x100 net/socket.c:2247
> >  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
> >  do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
> >  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> > RIP: 0033:0x7faade790d5c
> > Code: 2a 5f 02 00 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 70 5f 02 00 48 8b
> > RSP: 002b:00007ffdd2e3b670 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
> > RAX: ffffffffffffffda RBX: 00007faadf514620 RCX: 00007faade790d5c
> > RDX: 0000000000000028 RSI: 00007faadf514670 RDI: 0000000000000003
> > RBP: 0000000000000000 R08: 00007ffdd2e3b6c4 R09: 000000000000000c
> > R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
> > R13: 0000000000000000 R14: 00007faadf514670 R15: 0000000000000000
> >  </TASK>
> > rcu: rcu_preempt kthread timer wakeup didn't happen for 10499 jiffies! g11321 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
> > rcu:    Possible timer handling issue on cpu=0 timer-softirq=4286
> > rcu: rcu_preempt kthread starved for 10500 jiffies! g11321 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
> > rcu:    Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
> > rcu: RCU grace-period kthread stack dump:
> > task:rcu_preempt     state:I stack:27224 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
> > Call Trace:
> >  <TASK>
> >  context_switch kernel/sched/core.c:5325 [inline]
> >  __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
> >  __schedule_loop kernel/sched/core.c:7011 [inline]
> >  schedule+0x165/0x360 kernel/sched/core.c:7026
> >  schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
> >  rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
> >  rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
> >  kthread+0x711/0x8a0 kernel/kthread.c:463
> >  ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
> >  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
> >  </TASK>
> >
> >
> > ---
> > If you want syzbot to run the reproducer, reply with:
> > #syz test: git://repo/address.git branch-or-commit-hash
> > If you attach or paste a git patch, syzbot will apply it before testing.
>
> Yet another taprio report.
>
> If taprio can not be fixed, perhaps we should remove it from the
> kernel, or clearly marked as broken.
> (Then ask syzbot to no longer include it)

Agreed on the challenge with taprio.
We need the stakeholders input: Vinicius - are you still working in
this space? Vladimir you also seem to have interest (or maybe nxp
does) in this?
At a minimum, we should mark it as broken unless the stakeholders want
to actively fix these issues.
Would syzbot still look at it if it was marked broken?

cheers,
jamal


^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [syzbot] [net?] [mm?] INFO: rcu detected stall in inet_rtm_newaddr (2)
  2025-10-12 15:46     ` Jamal Hadi Salim
@ 2025-10-12 15:52       ` Jamal Hadi Salim
  2025-10-14 20:11         ` Vladimir Oltean
  2025-10-13 21:51       ` Vinicius Costa Gomes
  1 sibling, 1 reply; 10+ messages in thread
From: Jamal Hadi Salim @ 2025-10-12 15:52 UTC (permalink / raw)
  To: Eric Dumazet
  Cc: syzbot, Vinicius Costa Gomes, davem, dsahern, hdanton, horms,
	kuba, linux-kernel, linux-mm, netdev, pabeni, syzkaller-bugs,
	tglx, Vladimir Oltean

On Sun, Oct 12, 2025 at 11:46 AM Jamal Hadi Salim <jhs@mojatatu.com> wrote:
>
> On Sat, Oct 11, 2025 at 5:42 AM Eric Dumazet <edumazet@google.com> wrote:
> >
> > On Sat, Oct 11, 2025 at 12:41 AM syzbot
> > <syzbot+51cd74c5dfeafd65e488@syzkaller.appspotmail.com> wrote:
> > >
> > > syzbot has found a reproducer for the following issue on:
> > >
> > > HEAD commit:    18a7e218cfcd Merge tag 'net-6.18-rc1' of git://git.kernel...
> > > git tree:       net-next
> > > console output: https://syzkaller.appspot.com/x/log.txt?x=12504dcd980000
> > > kernel config:  https://syzkaller.appspot.com/x/.config?x=61ab7fa743df0ec1
> > > dashboard link: https://syzkaller.appspot.com/bug?extid=51cd74c5dfeafd65e488
> > > compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
> > > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14d2a542580000
> > > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=142149e2580000
> > >
> > > Downloadable assets:
> > > disk image: https://storage.googleapis.com/syzbot-assets/7a01e6dce97e/disk-18a7e218.raw.xz
> > > vmlinux: https://storage.googleapis.com/syzbot-assets/5e1b7e41427f/vmlinux-18a7e218.xz
> > > kernel image: https://storage.googleapis.com/syzbot-assets/69b558601209/bzImage-18a7e218.xz
> > >
> > > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > > Reported-by: syzbot+51cd74c5dfeafd65e488@syzkaller.appspotmail.com
> > >
> > > sched: DL replenish lagged too much
> > > rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
> > > rcu:    0-...!: (2 GPs behind) idle=7754/1/0x4000000000000000 softirq=15464/15465 fqs=1
> > > rcu:    (detected by 1, t=10502 jiffies, g=11321, q=371 ncpus=2)
> > > Sending NMI from CPU 1 to CPUs 0:
> > > NMI backtrace for cpu 0
> > > CPU: 0 UID: 0 PID: 5948 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
> > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
> > > RIP: 0010:rb_insert_color_cached include/linux/rbtree.h:113 [inline]
> > > RIP: 0010:rb_add_cached include/linux/rbtree.h:183 [inline]
> > > RIP: 0010:timerqueue_add+0x1a8/0x200 lib/timerqueue.c:40
> > > Code: e7 31 f6 e8 6a 0c de f6 42 80 3c 2b 00 74 08 4c 89 f7 e8 7b 0a de f6 4d 89 26 4d 8d 7e 08 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 <74> 08 4c 89 ff e8 5e 0a de f6 4d 89 27 4d 85 e4 40 0f 95 c5 eb 07
> > > RSP: 0018:ffffc90000007cf0 EFLAGS: 00000046
> > > RAX: 1ffff110170c4f83 RBX: 1ffff110170c4f82 RCX: 0000000000000000
> > > RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88805de72358
> > > RBP: 0000000000000000 R08: ffff88805de72357 R09: 0000000000000000
> > > R10: ffff88805de72340 R11: ffffed100bbce46b R12: ffff88805de72340
> > > R13: dffffc0000000000 R14: ffff8880b8627c10 R15: ffff8880b8627c18
> > > FS:  000055557c657500(0000) GS:ffff888125d0f000(0000) knlGS:0000000000000000
> > > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > > CR2: 0000200000000600 CR3: 000000002ee76000 CR4: 00000000003526f0
> > > Call Trace:
> > >  <IRQ>
> > >  __run_hrtimer kernel/time/hrtimer.c:1794 [inline]
> > >  __hrtimer_run_queues+0x656/0xc60 kernel/time/hrtimer.c:1841
> > >  hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
> > >  local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
> > >  __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1058
> > >  instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
> > >  sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052
> > >  </IRQ>
> > >  <TASK>
> > >  asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
> > > RIP: 0010:pv_vcpu_is_preempted arch/x86/include/asm/paravirt.h:579 [inline]
> > > RIP: 0010:vcpu_is_preempted arch/x86/include/asm/qspinlock.h:63 [inline]
> > > RIP: 0010:owner_on_cpu include/linux/sched.h:2282 [inline]
> > > RIP: 0010:mutex_spin_on_owner+0x189/0x360 kernel/locking/mutex.c:361
> > > Code: b6 04 30 84 c0 0f 85 59 01 00 00 48 8b 44 24 08 8b 18 48 8b 44 24 48 42 80 3c 30 00 74 0c 48 c7 c7 90 8c fa 8d e8 a7 cd 88 00 <48> 83 3d ff 27 5e 0c 00 0f 84 b9 01 00 00 48 89 df e8 41 e0 d5 ff
> > > RSP: 0018:ffffc900034c7428 EFLAGS: 00000246
> > > RAX: 1ffffffff1bf5192 RBX: 0000000000000001 RCX: ffffffff819c6588
> > > RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8f4df8a0
> > > RBP: 1ffffffff1e9bf14 R08: ffffffff8f4df8a7 R09: 1ffffffff1e9bf14
> > > R10: dffffc0000000000 R11: fffffbfff1e9bf15 R12: ffffffff8f4df8a0
> > > R13: ffffffff8f4df8f0 R14: dffffc0000000000 R15: ffff8880267a9e40
> > >  mutex_optimistic_spin kernel/locking/mutex.c:464 [inline]
> > >  __mutex_lock_common kernel/locking/mutex.c:602 [inline]
> > >  __mutex_lock+0x311/0x1350 kernel/locking/mutex.c:760
> > >  rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
> > >  inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978
> > >  rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6954
> > >  netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2552
> > >  netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
> > >  netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346
> > >  netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
> > >  sock_sendmsg_nosec net/socket.c:727 [inline]
> > >  __sock_sendmsg+0x21c/0x270 net/socket.c:742
> > >  __sys_sendto+0x3bd/0x520 net/socket.c:2244
> > >  __do_sys_sendto net/socket.c:2251 [inline]
> > >  __se_sys_sendto net/socket.c:2247 [inline]
> > >  __x64_sys_sendto+0xde/0x100 net/socket.c:2247
> > >  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
> > >  do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
> > >  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> > > RIP: 0033:0x7faade790d5c
> > > Code: 2a 5f 02 00 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 70 5f 02 00 48 8b
> > > RSP: 002b:00007ffdd2e3b670 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
> > > RAX: ffffffffffffffda RBX: 00007faadf514620 RCX: 00007faade790d5c
> > > RDX: 0000000000000028 RSI: 00007faadf514670 RDI: 0000000000000003
> > > RBP: 0000000000000000 R08: 00007ffdd2e3b6c4 R09: 000000000000000c
> > > R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
> > > R13: 0000000000000000 R14: 00007faadf514670 R15: 0000000000000000
> > >  </TASK>
> > > rcu: rcu_preempt kthread timer wakeup didn't happen for 10499 jiffies! g11321 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
> > > rcu:    Possible timer handling issue on cpu=0 timer-softirq=4286
> > > rcu: rcu_preempt kthread starved for 10500 jiffies! g11321 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
> > > rcu:    Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
> > > rcu: RCU grace-period kthread stack dump:
> > > task:rcu_preempt     state:I stack:27224 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
> > > Call Trace:
> > >  <TASK>
> > >  context_switch kernel/sched/core.c:5325 [inline]
> > >  __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
> > >  __schedule_loop kernel/sched/core.c:7011 [inline]
> > >  schedule+0x165/0x360 kernel/sched/core.c:7026
> > >  schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
> > >  rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
> > >  rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
> > >  kthread+0x711/0x8a0 kernel/kthread.c:463
> > >  ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
> > >  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
> > >  </TASK>
> > >
> > >
> > > ---
> > > If you want syzbot to run the reproducer, reply with:
> > > #syz test: git://repo/address.git branch-or-commit-hash
> > > If you attach or paste a git patch, syzbot will apply it before testing.
> >
> > Yet another taprio report.
> >
> > If taprio can not be fixed, perhaps we should remove it from the
> > kernel, or clearly marked as broken.
> > (Then ask syzbot to no longer include it)
>
> Agreed on the challenge with taprio.
> We need the stakeholders input: Vinicius - are you still working in
> this space? Vladimir you also seem to have interest (or maybe nxp
> does) in this?

+ Vladmir..

> At a minimum, we should mark it as broken unless the stakeholders want
> to actively fix these issues.
> Would syzbot still look at it if it was marked broken?
>
> cheers,
> jamal


^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [syzbot] [net?] [mm?] INFO: rcu detected stall in inet_rtm_newaddr (2)
  2025-10-12 15:52       ` Jamal Hadi Salim
@ 2025-10-14 20:11         ` Vladimir Oltean
  2025-10-15 21:50           ` Jamal Hadi Salim
  0 siblings, 1 reply; 10+ messages in thread
From: Vladimir Oltean @ 2025-10-14 20:11 UTC (permalink / raw)
  To: Jamal Hadi Salim
  Cc: Eric Dumazet, syzbot, Vinicius Costa Gomes, davem, dsahern,
	hdanton, horms, kuba, linux-kernel, linux-mm, netdev, pabeni,
	syzkaller-bugs, tglx

Hi Jamal,

On Sun, Oct 12, 2025 at 11:52:54AM -0400, Jamal Hadi Salim wrote:
> > > Yet another taprio report.
> > >
> > > If taprio can not be fixed, perhaps we should remove it from the
> > > kernel, or clearly marked as broken.
> > > (Then ask syzbot to no longer include it)
> >
> > Agreed on the challenge with taprio.
> > We need the stakeholders input: Vinicius - are you still working in
> > this space? Vladimir you also seem to have interest (or maybe nxp
> > does) in this?
> 
> + Vladmir..
> 
> > At a minimum, we should mark it as broken unless the stakeholders want
> > to actively fix these issues.
> > Would syzbot still look at it if it was marked broken?

I still have interest in taprio, but at the moment I can't look at this
any sooner than the second half of next week (unless someone else beats
me to it). I've added a note not to lose track.

What is the situation with syzbot reports? I don't actively monitor them,
only if somebody happens to email me.


^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [syzbot] [net?] [mm?] INFO: rcu detected stall in inet_rtm_newaddr (2)
  2025-10-14 20:11         ` Vladimir Oltean
@ 2025-10-15 21:50           ` Jamal Hadi Salim
  0 siblings, 0 replies; 10+ messages in thread
From: Jamal Hadi Salim @ 2025-10-15 21:50 UTC (permalink / raw)
  To: Vladimir Oltean
  Cc: Eric Dumazet, syzbot, Vinicius Costa Gomes, davem, dsahern,
	hdanton, horms, kuba, linux-kernel, linux-mm, netdev, pabeni,
	syzkaller-bugs, tglx

On Tue, Oct 14, 2025 at 4:11 PM Vladimir Oltean <vladimir.oltean@nxp.com> wrote:
>
> Hi Jamal,
>
> On Sun, Oct 12, 2025 at 11:52:54AM -0400, Jamal Hadi Salim wrote:
> > > > Yet another taprio report.
> > > >
> > > > If taprio can not be fixed, perhaps we should remove it from the
> > > > kernel, or clearly marked as broken.
> > > > (Then ask syzbot to no longer include it)
> > >
> > > Agreed on the challenge with taprio.
> > > We need the stakeholders input: Vinicius - are you still working in
> > > this space? Vladimir you also seem to have interest (or maybe nxp
> > > does) in this?
> >
> > + Vladmir..
> >
> > > At a minimum, we should mark it as broken unless the stakeholders want
> > > to actively fix these issues.
> > > Would syzbot still look at it if it was marked broken?
>
> I still have interest in taprio, but at the moment I can't look at this
> any sooner than the second half of next week (unless someone else beats
> me to it). I've added a note not to lose track.
>

Thanks!

> What is the situation with syzbot reports? I don't actively monitor them,
> only if somebody happens to email me.

These issues have been lingering forever..
They do get posted on the list. Here are samples:
https://lore.kernel.org/netdev/676d25b2.050a0220.2f3838.0464.GAE@google.com/#r
https://lore.kernel.org/netdev/67d2a576.050a0220.14e108.0030.GAE@google.com/
https://lore.kernel.org/netdev/67946a0c.050a0220.3ab881.0010.GAE@google.com/
https://lore.kernel.org/netdev/66e96979.050a0220.252d9a.000a.GAE@google.com/
https://lore.kernel.org/netdev/6777334a.050a0220.3a8527.0058.GAE@google.com/#t

They all point to the same bisected commit, but am not sure whether
they are the same issue

To get you on Cc from syzbot - i think we'll have to add you as a
maintainer for taprio if you'd be okk with that..

cheers,
jamal


^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [syzbot] [net?] [mm?] INFO: rcu detected stall in inet_rtm_newaddr (2)
  2025-10-12 15:46     ` Jamal Hadi Salim
  2025-10-12 15:52       ` Jamal Hadi Salim
@ 2025-10-13 21:51       ` Vinicius Costa Gomes
  2025-10-15 21:36         ` Jamal Hadi Salim
  1 sibling, 1 reply; 10+ messages in thread
From: Vinicius Costa Gomes @ 2025-10-13 21:51 UTC (permalink / raw)
  To: Jamal Hadi Salim, Eric Dumazet
  Cc: syzbot, davem, dsahern, hdanton, horms, kuba, linux-kernel,
	linux-mm, netdev, pabeni, syzkaller-bugs, tglx

Jamal Hadi Salim <jhs@mojatatu.com> writes:

> On Sat, Oct 11, 2025 at 5:42 AM Eric Dumazet <edumazet@google.com> wrote:
>>
>> On Sat, Oct 11, 2025 at 12:41 AM syzbot
>> <syzbot+51cd74c5dfeafd65e488@syzkaller.appspotmail.com> wrote:
>> >
>> > syzbot has found a reproducer for the following issue on:
>> >
>> > HEAD commit:    18a7e218cfcd Merge tag 'net-6.18-rc1' of git://git.kernel...
>> > git tree:       net-next
>> > console output: https://syzkaller.appspot.com/x/log.txt?x=12504dcd980000
>> > kernel config:  https://syzkaller.appspot.com/x/.config?x=61ab7fa743df0ec1
>> > dashboard link: https://syzkaller.appspot.com/bug?extid=51cd74c5dfeafd65e488
>> > compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
>> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14d2a542580000
>> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=142149e2580000
>> >
>> > Downloadable assets:
>> > disk image: https://storage.googleapis.com/syzbot-assets/7a01e6dce97e/disk-18a7e218.raw.xz
>> > vmlinux: https://storage.googleapis.com/syzbot-assets/5e1b7e41427f/vmlinux-18a7e218.xz
>> > kernel image: https://storage.googleapis.com/syzbot-assets/69b558601209/bzImage-18a7e218.xz
>> >
>> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> > Reported-by: syzbot+51cd74c5dfeafd65e488@syzkaller.appspotmail.com
>> >
>> > sched: DL replenish lagged too much
>> > rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
>> > rcu:    0-...!: (2 GPs behind) idle=7754/1/0x4000000000000000 softirq=15464/15465 fqs=1
>> > rcu:    (detected by 1, t=10502 jiffies, g=11321, q=371 ncpus=2)
>> > Sending NMI from CPU 1 to CPUs 0:
>> > NMI backtrace for cpu 0
>> > CPU: 0 UID: 0 PID: 5948 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
>> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
>> > RIP: 0010:rb_insert_color_cached include/linux/rbtree.h:113 [inline]
>> > RIP: 0010:rb_add_cached include/linux/rbtree.h:183 [inline]
>> > RIP: 0010:timerqueue_add+0x1a8/0x200 lib/timerqueue.c:40
>> > Code: e7 31 f6 e8 6a 0c de f6 42 80 3c 2b 00 74 08 4c 89 f7 e8 7b 0a de f6 4d 89 26 4d 8d 7e 08 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 <74> 08 4c 89 ff e8 5e 0a de f6 4d 89 27 4d 85 e4 40 0f 95 c5 eb 07
>> > RSP: 0018:ffffc90000007cf0 EFLAGS: 00000046
>> > RAX: 1ffff110170c4f83 RBX: 1ffff110170c4f82 RCX: 0000000000000000
>> > RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88805de72358
>> > RBP: 0000000000000000 R08: ffff88805de72357 R09: 0000000000000000
>> > R10: ffff88805de72340 R11: ffffed100bbce46b R12: ffff88805de72340
>> > R13: dffffc0000000000 R14: ffff8880b8627c10 R15: ffff8880b8627c18
>> > FS:  000055557c657500(0000) GS:ffff888125d0f000(0000) knlGS:0000000000000000
>> > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> > CR2: 0000200000000600 CR3: 000000002ee76000 CR4: 00000000003526f0
>> > Call Trace:
>> >  <IRQ>
>> >  __run_hrtimer kernel/time/hrtimer.c:1794 [inline]
>> >  __hrtimer_run_queues+0x656/0xc60 kernel/time/hrtimer.c:1841
>> >  hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
>> >  local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
>> >  __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1058
>> >  instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
>> >  sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052
>> >  </IRQ>
>> >  <TASK>
>> >  asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
>> > RIP: 0010:pv_vcpu_is_preempted arch/x86/include/asm/paravirt.h:579 [inline]
>> > RIP: 0010:vcpu_is_preempted arch/x86/include/asm/qspinlock.h:63 [inline]
>> > RIP: 0010:owner_on_cpu include/linux/sched.h:2282 [inline]
>> > RIP: 0010:mutex_spin_on_owner+0x189/0x360 kernel/locking/mutex.c:361
>> > Code: b6 04 30 84 c0 0f 85 59 01 00 00 48 8b 44 24 08 8b 18 48 8b 44 24 48 42 80 3c 30 00 74 0c 48 c7 c7 90 8c fa 8d e8 a7 cd 88 00 <48> 83 3d ff 27 5e 0c 00 0f 84 b9 01 00 00 48 89 df e8 41 e0 d5 ff
>> > RSP: 0018:ffffc900034c7428 EFLAGS: 00000246
>> > RAX: 1ffffffff1bf5192 RBX: 0000000000000001 RCX: ffffffff819c6588
>> > RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8f4df8a0
>> > RBP: 1ffffffff1e9bf14 R08: ffffffff8f4df8a7 R09: 1ffffffff1e9bf14
>> > R10: dffffc0000000000 R11: fffffbfff1e9bf15 R12: ffffffff8f4df8a0
>> > R13: ffffffff8f4df8f0 R14: dffffc0000000000 R15: ffff8880267a9e40
>> >  mutex_optimistic_spin kernel/locking/mutex.c:464 [inline]
>> >  __mutex_lock_common kernel/locking/mutex.c:602 [inline]
>> >  __mutex_lock+0x311/0x1350 kernel/locking/mutex.c:760
>> >  rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
>> >  inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978
>> >  rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6954
>> >  netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2552
>> >  netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
>> >  netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346
>> >  netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
>> >  sock_sendmsg_nosec net/socket.c:727 [inline]
>> >  __sock_sendmsg+0x21c/0x270 net/socket.c:742
>> >  __sys_sendto+0x3bd/0x520 net/socket.c:2244
>> >  __do_sys_sendto net/socket.c:2251 [inline]
>> >  __se_sys_sendto net/socket.c:2247 [inline]
>> >  __x64_sys_sendto+0xde/0x100 net/socket.c:2247
>> >  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
>> >  do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
>> >  entry_SYSCALL_64_after_hwframe+0x77/0x7f
>> > RIP: 0033:0x7faade790d5c
>> > Code: 2a 5f 02 00 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 70 5f 02 00 48 8b
>> > RSP: 002b:00007ffdd2e3b670 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
>> > RAX: ffffffffffffffda RBX: 00007faadf514620 RCX: 00007faade790d5c
>> > RDX: 0000000000000028 RSI: 00007faadf514670 RDI: 0000000000000003
>> > RBP: 0000000000000000 R08: 00007ffdd2e3b6c4 R09: 000000000000000c
>> > R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
>> > R13: 0000000000000000 R14: 00007faadf514670 R15: 0000000000000000
>> >  </TASK>
>> > rcu: rcu_preempt kthread timer wakeup didn't happen for 10499 jiffies! g11321 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
>> > rcu:    Possible timer handling issue on cpu=0 timer-softirq=4286
>> > rcu: rcu_preempt kthread starved for 10500 jiffies! g11321 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
>> > rcu:    Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
>> > rcu: RCU grace-period kthread stack dump:
>> > task:rcu_preempt     state:I stack:27224 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
>> > Call Trace:
>> >  <TASK>
>> >  context_switch kernel/sched/core.c:5325 [inline]
>> >  __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
>> >  __schedule_loop kernel/sched/core.c:7011 [inline]
>> >  schedule+0x165/0x360 kernel/sched/core.c:7026
>> >  schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
>> >  rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
>> >  rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
>> >  kthread+0x711/0x8a0 kernel/kthread.c:463
>> >  ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
>> >  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
>> >  </TASK>
>> >
>> >
>> > ---
>> > If you want syzbot to run the reproducer, reply with:
>> > #syz test: git://repo/address.git branch-or-commit-hash
>> > If you attach or paste a git patch, syzbot will apply it before testing.
>>
>> Yet another taprio report.
>>
>> If taprio can not be fixed, perhaps we should remove it from the
>> kernel, or clearly marked as broken.
>> (Then ask syzbot to no longer include it)
>
> Agreed on the challenge with taprio.
> We need the stakeholders input: Vinicius - are you still working in
> this space? Vladimir you also seem to have interest (or maybe nxp
> does) in this?

No, I am not working on this space anymore.

I will talk with other Intel folks (and my manager) and see what we can
do. But if others that find it useful can help even better.

> At a minimum, we should mark it as broken unless the stakeholders want
> to actively fix these issues.
> Would syzbot still look at it if it was marked broken?
>
> cheers,
> jamal
>


Cheers,
-- 
Vinicius


^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [syzbot] [net?] [mm?] INFO: rcu detected stall in inet_rtm_newaddr (2)
  2025-10-13 21:51       ` Vinicius Costa Gomes
@ 2025-10-15 21:36         ` Jamal Hadi Salim
  2025-10-15 22:30           ` Vinicius Costa Gomes
  0 siblings, 1 reply; 10+ messages in thread
From: Jamal Hadi Salim @ 2025-10-15 21:36 UTC (permalink / raw)
  To: Vinicius Costa Gomes
  Cc: Eric Dumazet, syzbot, davem, dsahern, hdanton, horms, kuba,
	linux-kernel, linux-mm, netdev, pabeni, syzkaller-bugs, tglx

On Mon, Oct 13, 2025 at 5:51 PM Vinicius Costa Gomes
<vinicius.gomes@intel.com> wrote:
>
> Jamal Hadi Salim <jhs@mojatatu.com> writes:
>
> > On Sat, Oct 11, 2025 at 5:42 AM Eric Dumazet <edumazet@google.com> wrote:
> >>
> >> On Sat, Oct 11, 2025 at 12:41 AM syzbot
> >> <syzbot+51cd74c5dfeafd65e488@syzkaller.appspotmail.com> wrote:
> >> >
> >> > syzbot has found a reproducer for the following issue on:
> >> >
> >> > HEAD commit:    18a7e218cfcd Merge tag 'net-6.18-rc1' of git://git.kernel...
> >> > git tree:       net-next
> >> > console output: https://syzkaller.appspot.com/x/log.txt?x=12504dcd980000
> >> > kernel config:  https://syzkaller.appspot.com/x/.config?x=61ab7fa743df0ec1
> >> > dashboard link: https://syzkaller.appspot.com/bug?extid=51cd74c5dfeafd65e488
> >> > compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
> >> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14d2a542580000
> >> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=142149e2580000
> >> >
> >> > Downloadable assets:
> >> > disk image: https://storage.googleapis.com/syzbot-assets/7a01e6dce97e/disk-18a7e218.raw.xz
> >> > vmlinux: https://storage.googleapis.com/syzbot-assets/5e1b7e41427f/vmlinux-18a7e218.xz
> >> > kernel image: https://storage.googleapis.com/syzbot-assets/69b558601209/bzImage-18a7e218.xz
> >> >
> >> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> >> > Reported-by: syzbot+51cd74c5dfeafd65e488@syzkaller.appspotmail.com
> >> >
> >> > sched: DL replenish lagged too much
> >> > rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
> >> > rcu:    0-...!: (2 GPs behind) idle=7754/1/0x4000000000000000 softirq=15464/15465 fqs=1
> >> > rcu:    (detected by 1, t=10502 jiffies, g=11321, q=371 ncpus=2)
> >> > Sending NMI from CPU 1 to CPUs 0:
> >> > NMI backtrace for cpu 0
> >> > CPU: 0 UID: 0 PID: 5948 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
> >> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
> >> > RIP: 0010:rb_insert_color_cached include/linux/rbtree.h:113 [inline]
> >> > RIP: 0010:rb_add_cached include/linux/rbtree.h:183 [inline]
> >> > RIP: 0010:timerqueue_add+0x1a8/0x200 lib/timerqueue.c:40
> >> > Code: e7 31 f6 e8 6a 0c de f6 42 80 3c 2b 00 74 08 4c 89 f7 e8 7b 0a de f6 4d 89 26 4d 8d 7e 08 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 <74> 08 4c 89 ff e8 5e 0a de f6 4d 89 27 4d 85 e4 40 0f 95 c5 eb 07
> >> > RSP: 0018:ffffc90000007cf0 EFLAGS: 00000046
> >> > RAX: 1ffff110170c4f83 RBX: 1ffff110170c4f82 RCX: 0000000000000000
> >> > RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88805de72358
> >> > RBP: 0000000000000000 R08: ffff88805de72357 R09: 0000000000000000
> >> > R10: ffff88805de72340 R11: ffffed100bbce46b R12: ffff88805de72340
> >> > R13: dffffc0000000000 R14: ffff8880b8627c10 R15: ffff8880b8627c18
> >> > FS:  000055557c657500(0000) GS:ffff888125d0f000(0000) knlGS:0000000000000000
> >> > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> >> > CR2: 0000200000000600 CR3: 000000002ee76000 CR4: 00000000003526f0
> >> > Call Trace:
> >> >  <IRQ>
> >> >  __run_hrtimer kernel/time/hrtimer.c:1794 [inline]
> >> >  __hrtimer_run_queues+0x656/0xc60 kernel/time/hrtimer.c:1841
> >> >  hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
> >> >  local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
> >> >  __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1058
> >> >  instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
> >> >  sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052
> >> >  </IRQ>
> >> >  <TASK>
> >> >  asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
> >> > RIP: 0010:pv_vcpu_is_preempted arch/x86/include/asm/paravirt.h:579 [inline]
> >> > RIP: 0010:vcpu_is_preempted arch/x86/include/asm/qspinlock.h:63 [inline]
> >> > RIP: 0010:owner_on_cpu include/linux/sched.h:2282 [inline]
> >> > RIP: 0010:mutex_spin_on_owner+0x189/0x360 kernel/locking/mutex.c:361
> >> > Code: b6 04 30 84 c0 0f 85 59 01 00 00 48 8b 44 24 08 8b 18 48 8b 44 24 48 42 80 3c 30 00 74 0c 48 c7 c7 90 8c fa 8d e8 a7 cd 88 00 <48> 83 3d ff 27 5e 0c 00 0f 84 b9 01 00 00 48 89 df e8 41 e0 d5 ff
> >> > RSP: 0018:ffffc900034c7428 EFLAGS: 00000246
> >> > RAX: 1ffffffff1bf5192 RBX: 0000000000000001 RCX: ffffffff819c6588
> >> > RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8f4df8a0
> >> > RBP: 1ffffffff1e9bf14 R08: ffffffff8f4df8a7 R09: 1ffffffff1e9bf14
> >> > R10: dffffc0000000000 R11: fffffbfff1e9bf15 R12: ffffffff8f4df8a0
> >> > R13: ffffffff8f4df8f0 R14: dffffc0000000000 R15: ffff8880267a9e40
> >> >  mutex_optimistic_spin kernel/locking/mutex.c:464 [inline]
> >> >  __mutex_lock_common kernel/locking/mutex.c:602 [inline]
> >> >  __mutex_lock+0x311/0x1350 kernel/locking/mutex.c:760
> >> >  rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
> >> >  inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978
> >> >  rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6954
> >> >  netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2552
> >> >  netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
> >> >  netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346
> >> >  netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
> >> >  sock_sendmsg_nosec net/socket.c:727 [inline]
> >> >  __sock_sendmsg+0x21c/0x270 net/socket.c:742
> >> >  __sys_sendto+0x3bd/0x520 net/socket.c:2244
> >> >  __do_sys_sendto net/socket.c:2251 [inline]
> >> >  __se_sys_sendto net/socket.c:2247 [inline]
> >> >  __x64_sys_sendto+0xde/0x100 net/socket.c:2247
> >> >  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
> >> >  do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
> >> >  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> >> > RIP: 0033:0x7faade790d5c
> >> > Code: 2a 5f 02 00 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 70 5f 02 00 48 8b
> >> > RSP: 002b:00007ffdd2e3b670 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
> >> > RAX: ffffffffffffffda RBX: 00007faadf514620 RCX: 00007faade790d5c
> >> > RDX: 0000000000000028 RSI: 00007faadf514670 RDI: 0000000000000003
> >> > RBP: 0000000000000000 R08: 00007ffdd2e3b6c4 R09: 000000000000000c
> >> > R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
> >> > R13: 0000000000000000 R14: 00007faadf514670 R15: 0000000000000000
> >> >  </TASK>
> >> > rcu: rcu_preempt kthread timer wakeup didn't happen for 10499 jiffies! g11321 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
> >> > rcu:    Possible timer handling issue on cpu=0 timer-softirq=4286
> >> > rcu: rcu_preempt kthread starved for 10500 jiffies! g11321 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
> >> > rcu:    Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
> >> > rcu: RCU grace-period kthread stack dump:
> >> > task:rcu_preempt     state:I stack:27224 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
> >> > Call Trace:
> >> >  <TASK>
> >> >  context_switch kernel/sched/core.c:5325 [inline]
> >> >  __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
> >> >  __schedule_loop kernel/sched/core.c:7011 [inline]
> >> >  schedule+0x165/0x360 kernel/sched/core.c:7026
> >> >  schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
> >> >  rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
> >> >  rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
> >> >  kthread+0x711/0x8a0 kernel/kthread.c:463
> >> >  ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
> >> >  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
> >> >  </TASK>
> >> >
> >> >
> >> > ---
> >> > If you want syzbot to run the reproducer, reply with:
> >> > #syz test: git://repo/address.git branch-or-commit-hash
> >> > If you attach or paste a git patch, syzbot will apply it before testing.
> >>
> >> Yet another taprio report.
> >>
> >> If taprio can not be fixed, perhaps we should remove it from the
> >> kernel, or clearly marked as broken.
> >> (Then ask syzbot to no longer include it)
> >
> > Agreed on the challenge with taprio.
> > We need the stakeholders input: Vinicius - are you still working in
> > this space? Vladimir you also seem to have interest (or maybe nxp
> > does) in this?
>
> No, I am not working on this space anymore.
>
> I will talk with other Intel folks (and my manager) and see what we can
> do.

I assume your customers are still interested in this working? If yes,
that would be a good pitch to the manager.
In my (extreme) view, another selling point is that there is an
ethical obligation to ensure things continue to work as intended.
Getting patches in is the easy part.

cheers,
jamal

>But if others that find it useful can help even better.
>


^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [syzbot] [net?] [mm?] INFO: rcu detected stall in inet_rtm_newaddr (2)
  2025-10-15 21:36         ` Jamal Hadi Salim
@ 2025-10-15 22:30           ` Vinicius Costa Gomes
  2025-10-24  0:11             ` Vinicius Costa Gomes
  0 siblings, 1 reply; 10+ messages in thread
From: Vinicius Costa Gomes @ 2025-10-15 22:30 UTC (permalink / raw)
  To: Jamal Hadi Salim
  Cc: Eric Dumazet, syzbot, davem, dsahern, hdanton, horms, kuba,
	linux-kernel, linux-mm, netdev, pabeni, syzkaller-bugs, tglx

Jamal Hadi Salim <jhs@mojatatu.com> writes:

> On Mon, Oct 13, 2025 at 5:51 PM Vinicius Costa Gomes
> <vinicius.gomes@intel.com> wrote:
>>
>> Jamal Hadi Salim <jhs@mojatatu.com> writes:
>>
>> > On Sat, Oct 11, 2025 at 5:42 AM Eric Dumazet <edumazet@google.com> wrote:
>> >>
>> >> On Sat, Oct 11, 2025 at 12:41 AM syzbot
>> >> <syzbot+51cd74c5dfeafd65e488@syzkaller.appspotmail.com> wrote:
>> >> >
>> >> > syzbot has found a reproducer for the following issue on:
>> >> >
>> >> > HEAD commit:    18a7e218cfcd Merge tag 'net-6.18-rc1' of git://git.kernel...
>> >> > git tree:       net-next
>> >> > console output: https://syzkaller.appspot.com/x/log.txt?x=12504dcd980000
>> >> > kernel config:  https://syzkaller.appspot.com/x/.config?x=61ab7fa743df0ec1
>> >> > dashboard link: https://syzkaller.appspot.com/bug?extid=51cd74c5dfeafd65e488
>> >> > compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
>> >> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14d2a542580000
>> >> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=142149e2580000
>> >> >
>> >> > Downloadable assets:
>> >> > disk image: https://storage.googleapis.com/syzbot-assets/7a01e6dce97e/disk-18a7e218.raw.xz
>> >> > vmlinux: https://storage.googleapis.com/syzbot-assets/5e1b7e41427f/vmlinux-18a7e218.xz
>> >> > kernel image: https://storage.googleapis.com/syzbot-assets/69b558601209/bzImage-18a7e218.xz
>> >> >
>> >> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> >> > Reported-by: syzbot+51cd74c5dfeafd65e488@syzkaller.appspotmail.com
>> >> >
>> >> > sched: DL replenish lagged too much
>> >> > rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
>> >> > rcu:    0-...!: (2 GPs behind) idle=7754/1/0x4000000000000000 softirq=15464/15465 fqs=1
>> >> > rcu:    (detected by 1, t=10502 jiffies, g=11321, q=371 ncpus=2)
>> >> > Sending NMI from CPU 1 to CPUs 0:
>> >> > NMI backtrace for cpu 0
>> >> > CPU: 0 UID: 0 PID: 5948 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
>> >> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
>> >> > RIP: 0010:rb_insert_color_cached include/linux/rbtree.h:113 [inline]
>> >> > RIP: 0010:rb_add_cached include/linux/rbtree.h:183 [inline]
>> >> > RIP: 0010:timerqueue_add+0x1a8/0x200 lib/timerqueue.c:40
>> >> > Code: e7 31 f6 e8 6a 0c de f6 42 80 3c 2b 00 74 08 4c 89 f7 e8 7b 0a de f6 4d 89 26 4d 8d 7e 08 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 <74> 08 4c 89 ff e8 5e 0a de f6 4d 89 27 4d 85 e4 40 0f 95 c5 eb 07
>> >> > RSP: 0018:ffffc90000007cf0 EFLAGS: 00000046
>> >> > RAX: 1ffff110170c4f83 RBX: 1ffff110170c4f82 RCX: 0000000000000000
>> >> > RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88805de72358
>> >> > RBP: 0000000000000000 R08: ffff88805de72357 R09: 0000000000000000
>> >> > R10: ffff88805de72340 R11: ffffed100bbce46b R12: ffff88805de72340
>> >> > R13: dffffc0000000000 R14: ffff8880b8627c10 R15: ffff8880b8627c18
>> >> > FS:  000055557c657500(0000) GS:ffff888125d0f000(0000) knlGS:0000000000000000
>> >> > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> >> > CR2: 0000200000000600 CR3: 000000002ee76000 CR4: 00000000003526f0
>> >> > Call Trace:
>> >> >  <IRQ>
>> >> >  __run_hrtimer kernel/time/hrtimer.c:1794 [inline]
>> >> >  __hrtimer_run_queues+0x656/0xc60 kernel/time/hrtimer.c:1841
>> >> >  hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
>> >> >  local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
>> >> >  __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1058
>> >> >  instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
>> >> >  sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052
>> >> >  </IRQ>
>> >> >  <TASK>
>> >> >  asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
>> >> > RIP: 0010:pv_vcpu_is_preempted arch/x86/include/asm/paravirt.h:579 [inline]
>> >> > RIP: 0010:vcpu_is_preempted arch/x86/include/asm/qspinlock.h:63 [inline]
>> >> > RIP: 0010:owner_on_cpu include/linux/sched.h:2282 [inline]
>> >> > RIP: 0010:mutex_spin_on_owner+0x189/0x360 kernel/locking/mutex.c:361
>> >> > Code: b6 04 30 84 c0 0f 85 59 01 00 00 48 8b 44 24 08 8b 18 48 8b 44 24 48 42 80 3c 30 00 74 0c 48 c7 c7 90 8c fa 8d e8 a7 cd 88 00 <48> 83 3d ff 27 5e 0c 00 0f 84 b9 01 00 00 48 89 df e8 41 e0 d5 ff
>> >> > RSP: 0018:ffffc900034c7428 EFLAGS: 00000246
>> >> > RAX: 1ffffffff1bf5192 RBX: 0000000000000001 RCX: ffffffff819c6588
>> >> > RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8f4df8a0
>> >> > RBP: 1ffffffff1e9bf14 R08: ffffffff8f4df8a7 R09: 1ffffffff1e9bf14
>> >> > R10: dffffc0000000000 R11: fffffbfff1e9bf15 R12: ffffffff8f4df8a0
>> >> > R13: ffffffff8f4df8f0 R14: dffffc0000000000 R15: ffff8880267a9e40
>> >> >  mutex_optimistic_spin kernel/locking/mutex.c:464 [inline]
>> >> >  __mutex_lock_common kernel/locking/mutex.c:602 [inline]
>> >> >  __mutex_lock+0x311/0x1350 kernel/locking/mutex.c:760
>> >> >  rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
>> >> >  inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978
>> >> >  rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6954
>> >> >  netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2552
>> >> >  netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
>> >> >  netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346
>> >> >  netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
>> >> >  sock_sendmsg_nosec net/socket.c:727 [inline]
>> >> >  __sock_sendmsg+0x21c/0x270 net/socket.c:742
>> >> >  __sys_sendto+0x3bd/0x520 net/socket.c:2244
>> >> >  __do_sys_sendto net/socket.c:2251 [inline]
>> >> >  __se_sys_sendto net/socket.c:2247 [inline]
>> >> >  __x64_sys_sendto+0xde/0x100 net/socket.c:2247
>> >> >  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
>> >> >  do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
>> >> >  entry_SYSCALL_64_after_hwframe+0x77/0x7f
>> >> > RIP: 0033:0x7faade790d5c
>> >> > Code: 2a 5f 02 00 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 70 5f 02 00 48 8b
>> >> > RSP: 002b:00007ffdd2e3b670 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
>> >> > RAX: ffffffffffffffda RBX: 00007faadf514620 RCX: 00007faade790d5c
>> >> > RDX: 0000000000000028 RSI: 00007faadf514670 RDI: 0000000000000003
>> >> > RBP: 0000000000000000 R08: 00007ffdd2e3b6c4 R09: 000000000000000c
>> >> > R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
>> >> > R13: 0000000000000000 R14: 00007faadf514670 R15: 0000000000000000
>> >> >  </TASK>
>> >> > rcu: rcu_preempt kthread timer wakeup didn't happen for 10499 jiffies! g11321 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
>> >> > rcu:    Possible timer handling issue on cpu=0 timer-softirq=4286
>> >> > rcu: rcu_preempt kthread starved for 10500 jiffies! g11321 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
>> >> > rcu:    Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
>> >> > rcu: RCU grace-period kthread stack dump:
>> >> > task:rcu_preempt     state:I stack:27224 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
>> >> > Call Trace:
>> >> >  <TASK>
>> >> >  context_switch kernel/sched/core.c:5325 [inline]
>> >> >  __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
>> >> >  __schedule_loop kernel/sched/core.c:7011 [inline]
>> >> >  schedule+0x165/0x360 kernel/sched/core.c:7026
>> >> >  schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
>> >> >  rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
>> >> >  rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
>> >> >  kthread+0x711/0x8a0 kernel/kthread.c:463
>> >> >  ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
>> >> >  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
>> >> >  </TASK>
>> >> >
>> >> >
>> >> > ---
>> >> > If you want syzbot to run the reproducer, reply with:
>> >> > #syz test: git://repo/address.git branch-or-commit-hash
>> >> > If you attach or paste a git patch, syzbot will apply it before testing.
>> >>
>> >> Yet another taprio report.
>> >>
>> >> If taprio can not be fixed, perhaps we should remove it from the
>> >> kernel, or clearly marked as broken.
>> >> (Then ask syzbot to no longer include it)
>> >
>> > Agreed on the challenge with taprio.
>> > We need the stakeholders input: Vinicius - are you still working in
>> > this space? Vladimir you also seem to have interest (or maybe nxp
>> > does) in this?
>>
>> No, I am not working on this space anymore.
>>
>> I will talk with other Intel folks (and my manager) and see what we can
>> do.
>
> I assume your customers are still interested in this working? If yes,
> that would be a good pitch to the manager.

I did talk with some people here, and let's just say that I am hearing
positive noises. So chances are that I should be able to dedicate some
of my "job time" to this area again.

> In my (extreme) view, another selling point is that there is an
> ethical obligation to ensure things continue to work as intended.
> Getting patches in is the easy part.
>
> cheers,
> jamal
>
>>But if others that find it useful can help even better.
>>
>


Cheers,
-- 
Vinicius


^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [syzbot] [net?] [mm?] INFO: rcu detected stall in inet_rtm_newaddr (2)
  2025-10-15 22:30           ` Vinicius Costa Gomes
@ 2025-10-24  0:11             ` Vinicius Costa Gomes
  0 siblings, 0 replies; 10+ messages in thread
From: Vinicius Costa Gomes @ 2025-10-24  0:11 UTC (permalink / raw)
  To: Jamal Hadi Salim
  Cc: Eric Dumazet, syzbot, davem, dsahern, hdanton, horms, kuba,
	linux-kernel, linux-mm, netdev, pabeni, syzkaller-bugs, tglx

Vinicius Costa Gomes <vinicius.gomes@intel.com> writes:

> Jamal Hadi Salim <jhs@mojatatu.com> writes:
>
>> On Mon, Oct 13, 2025 at 5:51 PM Vinicius Costa Gomes
>> <vinicius.gomes@intel.com> wrote:
>>>
>>> Jamal Hadi Salim <jhs@mojatatu.com> writes:
>>>
>>> > On Sat, Oct 11, 2025 at 5:42 AM Eric Dumazet <edumazet@google.com> wrote:
>>> >>
>>> >> On Sat, Oct 11, 2025 at 12:41 AM syzbot
>>> >> <syzbot+51cd74c5dfeafd65e488@syzkaller.appspotmail.com> wrote:
>>> >> >
>>> >> > syzbot has found a reproducer for the following issue on:
>>> >> >
>>> >> > HEAD commit:    18a7e218cfcd Merge tag 'net-6.18-rc1' of git://git.kernel...
>>> >> > git tree:       net-next
>>> >> > console output: https://syzkaller.appspot.com/x/log.txt?x=12504dcd980000
>>> >> > kernel config:  https://syzkaller.appspot.com/x/.config?x=61ab7fa743df0ec1
>>> >> > dashboard link: https://syzkaller.appspot.com/bug?extid=51cd74c5dfeafd65e488
>>> >> > compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
>>> >> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14d2a542580000
>>> >> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=142149e2580000
>>> >> >
>>> >> > Downloadable assets:
>>> >> > disk image: https://storage.googleapis.com/syzbot-assets/7a01e6dce97e/disk-18a7e218.raw.xz
>>> >> > vmlinux: https://storage.googleapis.com/syzbot-assets/5e1b7e41427f/vmlinux-18a7e218.xz
>>> >> > kernel image: https://storage.googleapis.com/syzbot-assets/69b558601209/bzImage-18a7e218.xz
>>> >> >
>>> >> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
>>> >> > Reported-by: syzbot+51cd74c5dfeafd65e488@syzkaller.appspotmail.com
>>> >> >
>>> >> > sched: DL replenish lagged too much
>>> >> > rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
>>> >> > rcu:    0-...!: (2 GPs behind) idle=7754/1/0x4000000000000000 softirq=15464/15465 fqs=1
>>> >> > rcu:    (detected by 1, t=10502 jiffies, g=11321, q=371 ncpus=2)
>>> >> > Sending NMI from CPU 1 to CPUs 0:
>>> >> > NMI backtrace for cpu 0
>>> >> > CPU: 0 UID: 0 PID: 5948 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
>>> >> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
>>> >> > RIP: 0010:rb_insert_color_cached include/linux/rbtree.h:113 [inline]
>>> >> > RIP: 0010:rb_add_cached include/linux/rbtree.h:183 [inline]
>>> >> > RIP: 0010:timerqueue_add+0x1a8/0x200 lib/timerqueue.c:40
>>> >> > Code: e7 31 f6 e8 6a 0c de f6 42 80 3c 2b 00 74 08 4c 89 f7 e8 7b 0a de f6 4d 89 26 4d 8d 7e 08 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 <74> 08 4c 89 ff e8 5e 0a de f6 4d 89 27 4d 85 e4 40 0f 95 c5 eb 07
>>> >> > RSP: 0018:ffffc90000007cf0 EFLAGS: 00000046
>>> >> > RAX: 1ffff110170c4f83 RBX: 1ffff110170c4f82 RCX: 0000000000000000
>>> >> > RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88805de72358
>>> >> > RBP: 0000000000000000 R08: ffff88805de72357 R09: 0000000000000000
>>> >> > R10: ffff88805de72340 R11: ffffed100bbce46b R12: ffff88805de72340
>>> >> > R13: dffffc0000000000 R14: ffff8880b8627c10 R15: ffff8880b8627c18
>>> >> > FS:  000055557c657500(0000) GS:ffff888125d0f000(0000) knlGS:0000000000000000
>>> >> > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>> >> > CR2: 0000200000000600 CR3: 000000002ee76000 CR4: 00000000003526f0
>>> >> > Call Trace:
>>> >> >  <IRQ>
>>> >> >  __run_hrtimer kernel/time/hrtimer.c:1794 [inline]
>>> >> >  __hrtimer_run_queues+0x656/0xc60 kernel/time/hrtimer.c:1841
>>> >> >  hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
>>> >> >  local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
>>> >> >  __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1058
>>> >> >  instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
>>> >> >  sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052
>>> >> >  </IRQ>
>>> >> >  <TASK>
>>> >> >  asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
>>> >> > RIP: 0010:pv_vcpu_is_preempted arch/x86/include/asm/paravirt.h:579 [inline]
>>> >> > RIP: 0010:vcpu_is_preempted arch/x86/include/asm/qspinlock.h:63 [inline]
>>> >> > RIP: 0010:owner_on_cpu include/linux/sched.h:2282 [inline]
>>> >> > RIP: 0010:mutex_spin_on_owner+0x189/0x360 kernel/locking/mutex.c:361
>>> >> > Code: b6 04 30 84 c0 0f 85 59 01 00 00 48 8b 44 24 08 8b 18 48 8b 44 24 48 42 80 3c 30 00 74 0c 48 c7 c7 90 8c fa 8d e8 a7 cd 88 00 <48> 83 3d ff 27 5e 0c 00 0f 84 b9 01 00 00 48 89 df e8 41 e0 d5 ff
>>> >> > RSP: 0018:ffffc900034c7428 EFLAGS: 00000246
>>> >> > RAX: 1ffffffff1bf5192 RBX: 0000000000000001 RCX: ffffffff819c6588
>>> >> > RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8f4df8a0
>>> >> > RBP: 1ffffffff1e9bf14 R08: ffffffff8f4df8a7 R09: 1ffffffff1e9bf14
>>> >> > R10: dffffc0000000000 R11: fffffbfff1e9bf15 R12: ffffffff8f4df8a0
>>> >> > R13: ffffffff8f4df8f0 R14: dffffc0000000000 R15: ffff8880267a9e40
>>> >> >  mutex_optimistic_spin kernel/locking/mutex.c:464 [inline]
>>> >> >  __mutex_lock_common kernel/locking/mutex.c:602 [inline]
>>> >> >  __mutex_lock+0x311/0x1350 kernel/locking/mutex.c:760
>>> >> >  rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
>>> >> >  inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978
>>> >> >  rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6954
>>> >> >  netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2552
>>> >> >  netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
>>> >> >  netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346
>>> >> >  netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
>>> >> >  sock_sendmsg_nosec net/socket.c:727 [inline]
>>> >> >  __sock_sendmsg+0x21c/0x270 net/socket.c:742
>>> >> >  __sys_sendto+0x3bd/0x520 net/socket.c:2244
>>> >> >  __do_sys_sendto net/socket.c:2251 [inline]
>>> >> >  __se_sys_sendto net/socket.c:2247 [inline]
>>> >> >  __x64_sys_sendto+0xde/0x100 net/socket.c:2247
>>> >> >  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
>>> >> >  do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
>>> >> >  entry_SYSCALL_64_after_hwframe+0x77/0x7f
>>> >> > RIP: 0033:0x7faade790d5c
>>> >> > Code: 2a 5f 02 00 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 70 5f 02 00 48 8b
>>> >> > RSP: 002b:00007ffdd2e3b670 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
>>> >> > RAX: ffffffffffffffda RBX: 00007faadf514620 RCX: 00007faade790d5c
>>> >> > RDX: 0000000000000028 RSI: 00007faadf514670 RDI: 0000000000000003
>>> >> > RBP: 0000000000000000 R08: 00007ffdd2e3b6c4 R09: 000000000000000c
>>> >> > R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
>>> >> > R13: 0000000000000000 R14: 00007faadf514670 R15: 0000000000000000
>>> >> >  </TASK>
>>> >> > rcu: rcu_preempt kthread timer wakeup didn't happen for 10499 jiffies! g11321 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
>>> >> > rcu:    Possible timer handling issue on cpu=0 timer-softirq=4286
>>> >> > rcu: rcu_preempt kthread starved for 10500 jiffies! g11321 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
>>> >> > rcu:    Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
>>> >> > rcu: RCU grace-period kthread stack dump:
>>> >> > task:rcu_preempt     state:I stack:27224 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
>>> >> > Call Trace:
>>> >> >  <TASK>
>>> >> >  context_switch kernel/sched/core.c:5325 [inline]
>>> >> >  __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
>>> >> >  __schedule_loop kernel/sched/core.c:7011 [inline]
>>> >> >  schedule+0x165/0x360 kernel/sched/core.c:7026
>>> >> >  schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
>>> >> >  rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
>>> >> >  rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
>>> >> >  kthread+0x711/0x8a0 kernel/kthread.c:463
>>> >> >  ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
>>> >> >  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
>>> >> >  </TASK>
>>> >> >
>>> >> >
>>> >> > ---
>>> >> > If you want syzbot to run the reproducer, reply with:
>>> >> > #syz test: git://repo/address.git branch-or-commit-hash
>>> >> > If you attach or paste a git patch, syzbot will apply it before testing.
>>> >>
>>> >> Yet another taprio report.
>>> >>
>>> >> If taprio can not be fixed, perhaps we should remove it from the
>>> >> kernel, or clearly marked as broken.
>>> >> (Then ask syzbot to no longer include it)
>>> >
>>> > Agreed on the challenge with taprio.
>>> > We need the stakeholders input: Vinicius - are you still working in
>>> > this space? Vladimir you also seem to have interest (or maybe nxp
>>> > does) in this?
>>>
>>> No, I am not working on this space anymore.
>>>
>>> I will talk with other Intel folks (and my manager) and see what we can
>>> do.
>>
>> I assume your customers are still interested in this working? If yes,
>> that would be a good pitch to the manager.
>
> I did talk with some people here, and let's just say that I am hearing
> positive noises. So chances are that I should be able to dedicate some
> of my "job time" to this area again.
>

Just a quick update, I got to spend some time on this, basically trying
to implement the idea here (that I had completely forgotten about):

https://lore.kernel.org/all/87jzftpwo2.fsf@intel.com/

Very early code, just to see how the code would look like is here:

https://github.com/vcgomes/net-next/tree/taprio-fix-syzkaller-report-clock-adjust

In case anyone is interested.

>> In my (extreme) view, another selling point is that there is an
>> ethical obligation to ensure things continue to work as intended.
>> Getting patches in is the easy part.
>>
>> cheers,
>> jamal
>>
>>>But if others that find it useful can help even better.
>>>
>>
>
>
> Cheers,
> -- 
> Vinicius
>


Cheers,
-- 
Vinicius


^ permalink raw reply	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2025-10-24  0:11 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
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2025-10-11  7:41 ` [syzbot] [net?] [mm?] INFO: rcu detected stall in inet_rtm_newaddr (2) syzbot
2025-10-11  9:42   ` Eric Dumazet
2025-10-12 15:46     ` Jamal Hadi Salim
2025-10-12 15:52       ` Jamal Hadi Salim
2025-10-14 20:11         ` Vladimir Oltean
2025-10-15 21:50           ` Jamal Hadi Salim
2025-10-13 21:51       ` Vinicius Costa Gomes
2025-10-15 21:36         ` Jamal Hadi Salim
2025-10-15 22:30           ` Vinicius Costa Gomes
2025-10-24  0:11             ` Vinicius Costa Gomes

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