* [syzbot] [mm?] INFO: rcu detected stall in finish_dput
@ 2025-12-15 4:03 syzbot
2025-12-29 4:10 ` syzbot
0 siblings, 1 reply; 2+ messages in thread
From: syzbot @ 2025-12-15 4:03 UTC (permalink / raw)
To: atomlin, da.gomez, linux-kernel, linux-mm, linux-modules, mcgrof,
petr.pavlu, samitolvanen, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: 8f0b4cce4481 Linux 6.19-rc1
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=119d511a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=a94030c847137a18
dashboard link: https://syzkaller.appspot.com/bug?extid=d1b2c58262854b97eb1f
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=10d38d92580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2b5022055115/disk-8f0b4cce.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/17c3669e328d/vmlinux-8f0b4cce.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7e72b5dbef4f/bzImage-8f0b4cce.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d1b2c58262854b97eb1f@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6163/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=13717, q=383 ncpus=2)
task:syz.2.19 state:R running task stack:26480 pid:6163 tgid:6163 ppid:5961 task_flags:0x40004c flags:0x00080001
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x14bc/0x5000 kernel/sched/core.c:6863
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7190
irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_release+0x2bb/0x3b0 kernel/locking/lockdep.c:5893
Code: 00 00 75 52 f7 c3 00 02 00 00 74 01 fb 65 48 8b 05 da 07 e0 10 48 3b 44 24 28 75 75 48 83 c4 30 5b 41 5c 41 5d 41 5e 41 5f 5d <e9> ab 98 71 ff cc 90 0f 0b 90 e9 70 fd ff ff 90 0f 0b 90 48 c7 c7
RSP: 0018:ffffc90003b8efd8 EFLAGS: 00000282
RAX: 670f1dcbf9e62d00 RBX: ffffffff81ac174d RCX: 670f1dcbf9e62d00
RDX: 0000000000000000 RSI: ffffffff8d978ed0 RDI: ffffffff8bc08360
RBP: 0000000000000000 R08: ffffffff81ac174d R09: ffffffff8df419e0
R10: dffffc0000000000 R11: ffffffff81ada000 R12: ffff888029131e80
R13: 1ffff92000771e38 R14: 00007f810118f749 R15: 1ffff92000771e16
rcu_lock_release include/linux/rcupdate.h:341 [inline]
rcu_read_unlock include/linux/rcupdate.h:897 [inline]
class_rcu_destructor include/linux/rcupdate.h:1195 [inline]
is_module_text_address+0x18b/0x1e0 kernel/module/main.c:3858
kernel_text_address+0x94/0xe0 kernel/extable.c:119
__kernel_text_address+0xd/0x40 kernel/extable.c:79
unwind_get_return_address+0x4d/0x90 arch/x86/kernel/unwind_orc.c:369
arch_stack_walk+0xfc/0x150 arch/x86/kernel/stacktrace.c:26
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
save_stack+0xf5/0x1f0 mm/page_owner.c:165
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1395 [inline]
free_unref_folios+0xdb3/0x14f0 mm/page_alloc.c:3000
folios_put_refs+0x584/0x670 mm/swap.c:1002
folio_batch_release include/linux/pagevec.h:101 [inline]
shmem_undo_range+0x49e/0x1490 mm/shmem.c:1137
shmem_truncate_range mm/shmem.c:1249 [inline]
shmem_evict_inode+0x26e/0xa70 mm/shmem.c:1379
evict+0x5f4/0xae0 fs/inode.c:837
__dentry_kill+0x209/0x660 fs/dcache.c:670
finish_dput+0xc9/0x480 fs/dcache.c:879
__fput+0x68e/0xa70 fs/file_table.c:476
task_work_run+0x1d4/0x260 kernel/task_work.c:233
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x6c5/0x2310 kernel/exit.c:971
do_group_exit+0x21c/0x2d0 kernel/exit.c:1112
__do_sys_exit_group kernel/exit.c:1123 [inline]
__se_sys_exit_group kernel/exit.c:1121 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1121
x64_sys_call+0x2210/0x2210 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f810118f749
RSP: 002b:00007ffdda280538 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f810118f749
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000003 R08: 0000000bda28062f R09: 00007f81013b4280
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f81013b4280 R14: 0000000000000003 R15: 00007ffdda2805f0
</TASK>
rcu: rcu_preempt kthread starved for 10546 jiffies! g13717 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:27128 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x14bc/0x5000 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6960
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+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 6168 Comm: syz.0.25 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:rdtsc_ordered arch/x86/include/asm/tsc.h:57 [inline]
RIP: 0010:read_tsc+0xc/0x20 arch/x86/kernel/tsc.c:1135
Code: e9 e8 fe ff ff e8 e4 c7 f2 09 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa e8 e7 c7 58 00 0f 01 f9 <66> 90 48 c1 e2 20 48 09 d0 e9 e1 57 a7 ff cc 0f 1f 44 00 00 90 90
RSP: 0000:ffffc90003077ac0 EFLAGS: 00000093
RAX: 0000000063ea710f RBX: ffffffff8dd73ac0 RCX: 0000000000000000
RDX: 000000000000008f RSI: 0000000000000000 RDI: ffffffff8dd73ac0
RBP: 000000000000b122 R08: ffffffff81af6795 R09: ffffffff998e3508
R10: 0000000000000003 R11: ffffffff8168e910 R12: 000000399661b39b
R13: dffffc0000000000 R14: 00000039b4a1e637 R15: dffffc0000000000
FS: 00007fd54d67f6c0(0000) GS:ffff888125e35000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000001c0 CR3: 0000000033588000 CR4: 0000000000350ef0
Call Trace:
<TASK>
tk_clock_read kernel/time/timekeeping.c:295 [inline]
timekeeping_get_ns kernel/time/timekeeping.c:404 [inline]
ktime_get+0x97/0x200 kernel/time/timekeeping.c:826
clockevents_program_event+0xe8/0x350 kernel/time/clockevents.c:326
hrtimer_start_range_ns+0xd8a/0x1080 kernel/time/hrtimer.c:1323
__posixtimer_deliver_signal kernel/time/posix-timers.c:321 [inline]
posixtimer_deliver_signal+0x1cf/0x410 kernel/time/posix-timers.c:347
dequeue_signal+0x24a/0x370 kernel/signal.c:660
get_signal+0x55e/0x1340 kernel/signal.c:2914
arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
exit_to_user_mode_loop kernel/entry/common.c:75 [inline]
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:270 [inline]
irqentry_exit_to_user_mode include/linux/irq-entry-common.h:339 [inline]
irqentry_exit+0x177/0x660 kernel/entry/common.c:196
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0033:0x7fd54c78f747
Code: ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 <0f> 05 48 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89
RSP: 002b:00007fd54d67f0e8 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007fd54c9e5fa8 RCX: 00007fd54c78f749
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fd54c9e5fa8
RBP: 00007fd54c9e5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd54c9e6038 R14: 00007ffeebd71e40 R15: 00007ffeebd71f28
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
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.
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [syzbot] [mm?] INFO: rcu detected stall in finish_dput
2025-12-15 4:03 [syzbot] [mm?] INFO: rcu detected stall in finish_dput syzbot
@ 2025-12-29 4:10 ` syzbot
0 siblings, 0 replies; 2+ messages in thread
From: syzbot @ 2025-12-29 4:10 UTC (permalink / raw)
To: atomlin, da.gomez, gregkh, linux-kernel, linux-mm, linux-modules,
mcgrof, petr.pavlu, samitolvanen, syzkaller-bugs, tj
syzbot has found a reproducer for the following issue on:
HEAD commit: cc3aa43b44bd Add linux-next specific files for 20251219
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=16918422580000
kernel config: https://syzkaller.appspot.com/x/.config?x=da1bc82c6189c463
dashboard link: https://syzkaller.appspot.com/bug?extid=d1b2c58262854b97eb1f
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=16937c9a580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11918422580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/30bf539e6f28/disk-cc3aa43b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0e2f8b08e342/vmlinux-cc3aa43b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ec7ee6ece11f/bzImage-cc3aa43b.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/b44ad9245927/mount_16.gz
fsck result: OK (log: https://syzkaller.appspot.com/x/fsck.log?x=139de49a580000)
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d1b2c58262854b97eb1f@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5981/1:b..l P8410/1:b..l P5988/1:b..l
rcu: (detected by 1, t=10503 jiffies, g=18665, q=488 ncpus=2)
task:syz-executor state:R running task stack:19496 pid:5988 tgid:5988 ppid:5980 task_flags:0x400140 flags:0x00080000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5258 [inline]
__schedule+0x150e/0x5070 kernel/sched/core.c:6866
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193
irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x16c/0x340 kernel/locking/lockdep.c:5872
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 44 41 01 11 <48> 3b 44 24 58 0f 85 e5 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc900041cf538 EFLAGS: 00000206
RAX: 32a75ba562c33400 RBX: 0000000000000000 RCX: 32a75ba562c33400
RDX: 000000005a44979c RSI: ffffffff8db7ed49 RDI: ffffffff8be07960
RBP: ffffffff81742f85 R08: ffffffff81742f85 R09: ffffffff8e13f2e0
R10: ffffc900041cf6f8 R11: ffffffff81ad9d50 R12: 0000000000000002
R13: ffffffff8e13f2e0 R14: 0000000000000000 R15: 0000000000000246
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:867 [inline]
class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
unwind_next_frame+0xc2/0x23d0 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
__call_rcu_common kernel/rcu/tree.c:3119 [inline]
call_rcu+0x157/0x9c0 kernel/rcu/tree.c:3239
__destroy_inode+0x2da/0x670 fs/inode.c:371
destroy_inode fs/inode.c:394 [inline]
evict+0x87d/0xae0 fs/inode.c:861
__dentry_kill+0x209/0x660 fs/dcache.c:670
finish_dput+0xc9/0x480 fs/dcache.c:879
__fput+0x68e/0xa70 fs/file_table.c:476
fput_close_sync+0x113/0x220 fs/file_table.c:573
__do_sys_close fs/open.c:1534 [inline]
__se_sys_close fs/open.c:1519 [inline]
__x64_sys_close+0x7f/0x110 fs/open.c:1519
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f53c018e3aa
RSP: 002b:00007fff1566c5c0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f53c018e3aa
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007fff1566c61c R08: 00007fff1566bf1c R09: 00007fff1566c327
R10: 00007fff1566bfa0 R11: 0000000000000293 R12: 000000000000003d
R13: 0000000000000059 R14: 00000000000789ec R15: 00007fff1566c670
</TASK>
task:btrfs-cleaner state:R running task stack:28144 pid:8410 tgid:8410 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5258 [inline]
__schedule+0x150e/0x5070 kernel/sched/core.c:6866
preempt_schedule_notrace+0xd1/0x110 kernel/sched/core.c:7143
preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13
rcu_is_watching+0x7f/0xb0 kernel/rcu/tree.c:752
trace_lock_release include/trace/events/lock.h:69 [inline]
lock_release+0x4b/0x3b0 kernel/locking/lockdep.c:5879
rcu_lock_release include/linux/rcupdate.h:341 [inline]
rcu_read_unlock include/linux/rcupdate.h:897 [inline]
class_rcu_destructor include/linux/rcupdate.h:1195 [inline]
unwind_next_frame+0x1ab1/0x23d0 arch/x86/kernel/unwind_orc.c:695
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
__call_rcu_common kernel/rcu/tree.c:3119 [inline]
call_rcu+0x157/0x9c0 kernel/rcu/tree.c:3239
kernfs_put+0x18e/0x470 fs/kernfs/dir.c:591
kernfs_remove_by_name_ns+0xb7/0x130 fs/kernfs/dir.c:1721
kernfs_remove_by_name include/linux/kernfs.h:633 [inline]
create_files fs/sysfs/group.c:66 [inline]
internal_create_group+0x57b/0x1170 fs/sysfs/group.c:189
btrfs_sysfs_feature_update+0x9b/0x1d0 fs/btrfs/sysfs.c:2689
cleaner_kthread+0x302/0x400 fs/btrfs/disk-io.c:1482
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
</TASK>
task:syz-executor state:R running task stack:19496 pid:5981 tgid:5981 ppid:5978 task_flags:0x400140 flags:0x00080000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5258 [inline]
__schedule+0x150e/0x5070 kernel/sched/core.c:6866
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193
irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_release+0x2a6/0x3b0 kernel/locking/lockdep.c:5893
Code: 4d 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 75 52 f7 c3 00 02 00 00 74 01 fb 65 48 8b 05 2a 0f 01 11 <48> 3b 44 24 28 75 75 48 83 c4 30 5b 41 5c 41 5d 41 5e 41 5f 5d e9
RSP: 0018:ffffc900041ff430 EFLAGS: 00000206
RAX: 56b6579f03543c00 RBX: 0000000000000202 RCX: 56b6579f03543c00
RDX: 0000000000000001 RSI: ffffffff8db7ed49 RDI: ffffffff8be07960
RBP: ffff88801cb58b58 R08: ffffc900041ff808 R09: 0000000000000000
R10: ffffc900041ff5b8 R11: fffff5200083feb9 R12: 0000000000000001
R13: 0000000000000001 R14: ffffffff8e13f2e0 R15: ffff88801cb58000
rcu_lock_release include/linux/rcupdate.h:341 [inline]
rcu_read_unlock include/linux/rcupdate.h:897 [inline]
class_rcu_destructor include/linux/rcupdate.h:1195 [inline]
unwind_next_frame+0x1ab1/0x23d0 arch/x86/kernel/unwind_orc.c:695
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
save_stack+0xf5/0x1f0 mm/page_owner.c:165
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1406 [inline]
__free_frozen_pages+0xbc8/0xd30 mm/page_alloc.c:2943
vfree+0x25a/0x400 mm/vmalloc.c:3504
copy_entries_to_user net/ipv4/netfilter/ip_tables.c:866 [inline]
get_entries net/ipv4/netfilter/ip_tables.c:1022 [inline]
do_ipt_get_ctl+0xebc/0x1180 net/ipv4/netfilter/ip_tables.c:1668
nf_getsockopt+0x26e/0x290 net/netfilter/nf_sockopt.c:116
ip_getsockopt+0x1c4/0x220 net/ipv4/ip_sockglue.c:1777
do_sock_getsockopt+0x2b4/0x3d0 net/socket.c:2398
__sys_getsockopt net/socket.c:2427 [inline]
__do_sys_getsockopt net/socket.c:2434 [inline]
__se_sys_getsockopt net/socket.c:2431 [inline]
__x64_sys_getsockopt+0x1a5/0x250 net/socket.c:2431
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb026b9148a
RSP: 002b:00007fff93b01148 EFLAGS: 00000212 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 00007fff93b011d0 RCX: 00007fb026b9148a
RDX: 0000000000000041 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000003 R08: 00007fff93b0116c R09: 00007fff93b01587
R10: 00007fff93b011d0 R11: 0000000000000212 R12: 00007fb026db8be0
R13: 00007fff93b0116c R14: 0000000000000000 R15: 00007fb026dba020
</TASK>
rcu: rcu_preempt kthread starved for 10620 jiffies! g18665 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:27728 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5258 [inline]
__schedule+0x150e/0x5070 kernel/sched/core.c:6866
__schedule_loop kernel/sched/core.c:6948 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6963
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+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 33 9e 2a 00 f3 0f 1e fa fb f4 <e9> 48 ee 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0000:ffffffff8de07d80 EFLAGS: 000002c6
RAX: 741d0ec708556100 RBX: ffffffff819786ba RCX: 741d0ec708556100
RDX: 0000000000000001 RSI: ffffffff8d997e54 RDI: ffffffff8be07960
RBP: ffffffff8de07ea8 R08: ffff8880b86336db R09: 1ffff110170c66db
R10: dffffc0000000000 R11: ffffed10170c66dc R12: ffffffff8fa22f70
R13: 1ffffffff1bd29b8 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125c25000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000755b0000 CR4: 00000000003526f0
Call Trace:
<TASK>
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x73/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x1ea/0x520 kernel/sched/idle.c:332
cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430
rest_init+0x2de/0x300 init/main.c:758
start_kernel+0x3ac/0x400 init/main.c:1208
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x147
</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] 2+ messages in thread
end of thread, other threads:[~2025-12-29 4:10 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2025-12-15 4:03 [syzbot] [mm?] INFO: rcu detected stall in finish_dput syzbot
2025-12-29 4:10 ` syzbot
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox