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b=pnm1HDqXgCoaXrOZyFT0QxLc7FDVvtAy69U3kEAiYALTcrdqZkLrH/Arej6Qhk4bN pUC9IM3cr2PqRtORe8L53JjEi075r3Dl87+9px11ts2dLqEEVICAY6EyZq8Fzt+gC+ EQ3F0M760NSHgPTzfgseeEz01EePDeHfj9sWpiwU= Date: Mon, 29 Jul 2024 14:31:12 -0700 From: Andrew Morton To: syzbot Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com, Dmitry Vyukov , Andrey Konovalov , kasan-dev@googlegroups.com, Aleksandr Nogikh , "Uladzislau Rezki (Sony)" Subject: Re: [syzbot] [mm?] INFO: rcu detected stall in kcov_ioctl (2) Message-Id: <20240729143112.3d713abe2bde51d718c7db93@linux-foundation.org> In-Reply-To: <0000000000000f67c9061e649949@google.com> References: <0000000000000f67c9061e649949@google.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: 7netqmtng5xwip31a8u7qq94kefr5xtw X-Rspamd-Queue-Id: 12DF340016 X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1722288674-210047 X-HE-Meta: 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 foqWIiLE mnO4ypiTRTnbKsUF7Ik4SxH9dw1EN+tDGIpxZnwwa3oGlnDZNtNtegOZSz2eZSMsLIsHV66m+MiHAbQAEGkRyfVl2fqIqO5K0zHq+kwN951g0gId4liv6WejtoXqfi+ygJlA3SLbUaP4ZRT4D7xSWkwTnijvJj0BV8DA26UblL2PR97/CMz60RW3rbJJG0HcTvo6V80WIXvi73aXf82LaZLOm5/ef01LMPcBZ1Y6ju60w0vTmZpprnhzFQfYPoop59CoxbO8OPGaLybUqMSONCHqgEso7jpjfupwdQb5S3Ug9gw5nka6KrvBku6qpm0L/cPiOYOLrvjIc81UStftjcKuq+SZSOUBtGROia4gB4djA5b31FyerQOc0S1GvDs1yBqRDVWQzRuYPk3OViZnwvmGfZ4SYca/eRpdHlc4ov2dnQ10m0TpRzl5xeMKadk0TL0h4PquptpJMvN5Mr3MLn0ur8+1T5/I4IULjVnB5Bvx7/Y/M5ccq94kvDH96/Wc3YPLreo2XJEsdJMRkTaakOtAvtGApVIMe7lHdZTxTjyR6hVUOUM+uc3FzUNpbH3HzwwH1LTu6SUFpK+3fBy8AN3ltQp6KXWu9VkG39Bi+Pxg9Yc0Cfuu0a3jjJDXX3eeQhpjsr/lHw/yLKY37+k4t9+sdKsRNNee0Pt9wbIzkkwlIG80CcB3xF7VMASKoWtp4vhNiuNeOglh/fi2qBEa46Dk8bZ4L09QkBg9lnPjIkiKXLZ9IPx0d6rYn20fo9q/WMfMcYQAjmeMRn0MxS1tiWmj5YIwl9jU8wV2GpqxWDaD6Kb2DLGHi7BaVJPzVEYP1nCpWSJk/M8ZfMVdO6FS+1ozhmniJ7V3eOB8aNiKY1C/sul4Vu4NnV+v2DmhjpRIzyfFFXGTuAj1hkrpByday6yzsTs1+RCOElKXnia3dSNkMLtnmz8wBLAXAtRIW99IuJZj4IbbpJliSRH+QY9t4GkNfi4+q /98vmEUz SJmgBEOwQzE8qml9ZLwEaLRsaJ8+csnm/LpojDyinEwD0v2xaD27SA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, 29 Jul 2024 08:34:33 -0700 syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 3a7e02c040b1 minmax: avoid overly complicated constant exp.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=132e32bd980000 > kernel config: https://syzkaller.appspot.com/x/.config?x=381b8eb3d35e3ad9 > dashboard link: https://syzkaller.appspot.com/bug?extid=ff2407cef5068e202465 > compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/198814da854c/disk-3a7e02c0.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/868e99275bc0/vmlinux-3a7e02c0.xz > kernel image: https://storage.googleapis.com/syzbot-assets/ce63033f3708/bzImage-3a7e02c0.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+ff2407cef5068e202465@syzkaller.appspotmail.com Thanks. Possibly kcov_ioctl(KCOV_INIT_TRACE) was passed a crazily huge size. Perhaps some more realistic checking should be applied there? Also, vmalloc() shouldn't be doing this even if asked to allocate a crazily huge size. > rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: > rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9645/1:b..l P9626/1:b..l > rcu: (detected by 0, t=10502 jiffies, g=53081, q=325 ncpus=2) > task:syz-executor state:R running task stack:27168 pid:9626 tgid:9626 ppid:5216 flags:0x00004002 > Call Trace: > > context_switch kernel/sched/core.c:5188 [inline] > __schedule+0xe37/0x5490 kernel/sched/core.c:6529 > preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:6851 > irqentry_exit+0x36/0x90 kernel/entry/common.c:354 > asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 > RIP: 0010:lock_acquire+0x1f2/0x560 kernel/locking/lockdep.c:5727 > Code: c1 05 3a 13 9a 7e 83 f8 01 0f 85 ea 02 00 00 9c 58 f6 c4 02 0f 85 d5 02 00 00 48 85 ed 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01 c3 48 c7 03 00 00 00 00 48 c7 43 08 00 00 00 00 48 8b 84 24 > RSP: 0018:ffffc90004647698 EFLAGS: 00000206 > RAX: dffffc0000000000 RBX: 1ffff920008c8ed5 RCX: 0000000000000001 > RDX: 0000000000000001 RSI: ffffffff8b4cc880 RDI: ffffffff8bb08c00 > RBP: 0000000000000200 R08: 0000000000000000 R09: fffffbfff28c4cd8 > R10: ffffffff946266c7 R11: 0000000000000000 R12: 0000000000000000 > R13: 0000000000000000 R14: ffffffff8ddb5220 R15: 0000000000000000 > rcu_lock_acquire include/linux/rcupdate.h:326 [inline] > rcu_read_lock include/linux/rcupdate.h:838 [inline] > page_ext_get+0x3a/0x310 mm/page_ext.c:535 > __set_page_owner+0x96/0x560 mm/page_owner.c:322 > set_page_owner include/linux/page_owner.h:32 [inline] > post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1493 > prep_new_page mm/page_alloc.c:1501 [inline] > get_page_from_freelist+0x1351/0x2e50 mm/page_alloc.c:3438 > __alloc_pages_noprof+0x22b/0x2460 mm/page_alloc.c:4696 > alloc_pages_mpol_noprof+0x275/0x610 mm/mempolicy.c:2263 > vm_area_alloc_pages mm/vmalloc.c:3584 [inline] > __vmalloc_area_node mm/vmalloc.c:3660 [inline] > __vmalloc_node_range_noprof+0xa6a/0x1520 mm/vmalloc.c:3841 > vmalloc_user_noprof+0x6b/0x90 mm/vmalloc.c:3995 > kcov_ioctl+0x4f/0x730 kernel/kcov.c:706 > vfs_ioctl fs/ioctl.c:51 [inline] > __do_sys_ioctl fs/ioctl.c:907 [inline] > __se_sys_ioctl fs/ioctl.c:893 [inline] > __x64_sys_ioctl+0x193/0x220 fs/ioctl.c:893 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > RIP: 0033:0x7fa518d76e9b > RSP: 002b:00007ffd114116d0 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 0000000000100000 RCX: 00007fa518d76e9b > RDX: 0000000000100000 RSI: ffffffff80086301 RDI: 00000000000000d7 > RBP: 00007fa518f05f40 R08: 00000000000000da R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 > R13: 0000000000000003 R14: 0000000000000009 R15: 0000000000000009 > > task:syz-executor state:R running task stack:27088 pid:9645 tgid:9645 ppid:5216 flags:0x00000002 > Call Trace: > > context_switch kernel/sched/core.c:5188 [inline] > __schedule+0xe37/0x5490 kernel/sched/core.c:6529 > preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:6708 > preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 > __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] > _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 > spin_unlock include/linux/spinlock.h:391 [inline] > insert_page mm/memory.c:2077 [inline] > vm_insert_page+0x45d/0x6d0 mm/memory.c:2226 > kcov_mmap+0xda/0x150 kernel/kcov.c:496 > call_mmap include/linux/fs.h:2129 [inline] > mmap_region+0x757/0x2760 mm/mmap.c:2957 > do_mmap+0xbfb/0xfb0 mm/mmap.c:1468 > vm_mmap_pgoff+0x1ba/0x360 mm/util.c:588 > ksys_mmap_pgoff+0x332/0x5d0 mm/mmap.c:1514 > __do_sys_mmap arch/x86/kernel/sys_x86_64.c:86 [inline] > __se_sys_mmap arch/x86/kernel/sys_x86_64.c:79 [inline] > __x64_sys_mmap+0x125/0x190 arch/x86/kernel/sys_x86_64.c:79 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > RIP: 0033:0x7f7bf4f772d3 > RSP: 002b:00007ffc20fff0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 > RAX: ffffffffffffffda RBX: 00007f7bf5106018 RCX: 00007f7bf4f772d3 > RDX: 0000000000000003 RSI: 0000000000200000 RDI: 00007f7bf4601000 > RBP: 00007f7bf4600000 R08: 00000000000000d8 R09: 0000000000000000 > R10: 0000000000000011 R11: 0000000000000246 R12: 000000000000000c > R13: 0000000000000003 R14: 0000000000000009 R15: 0000000000000009 > > rcu: rcu_preempt kthread starved for 10561 jiffies! g53081 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:27312 pid:17 tgid:17 ppid:2 flags:0x00004000 > Call Trace: > > context_switch kernel/sched/core.c:5188 [inline] > __schedule+0xe37/0x5490 kernel/sched/core.c:6529 > __schedule_loop kernel/sched/core.c:6606 [inline] > schedule+0xe7/0x350 kernel/sched/core.c:6621 > schedule_timeout+0x136/0x2a0 kernel/time/timer.c:2581 > rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:2034 > rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:2236 > kthread+0x2c1/0x3a0 kernel/kthread.c:389 > ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > > rcu: Stack dump where RCU GP kthread last ran: > CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.10.0-syzkaller-12710-g3a7e02c040b1 #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 > RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline] > RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:92 [inline] > RIP: 0010:acpi_safe_halt+0x1a/0x20 drivers/acpi/processor_idle.c:112 > Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 65 48 8b 05 48 69 f2 74 48 8b 00 a8 08 75 0c 66 90 0f 00 2d b8 82 aa 00 fb f4 c3 cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 > RSP: 0018:ffffffff8da07d70 EFLAGS: 00000246 > RAX: 0000000000004000 RBX: 0000000000000001 RCX: ffffffff8b115519 > RDX: 0000000000000001 RSI: ffff88801a2cb800 RDI: ffff88801a2cb864 > RBP: ffff88801a2cb864 R08: 0000000000000001 R09: ffffed1017246fe1 > R10: ffff8880b9237f0b R11: 0000000000000000 R12: ffff88801c70a800 > R13: ffffffff8e94eac0 R14: 0000000000000000 R15: 0000000000000000 > FS: 0000000000000000(0000) GS:ffff8880b9200000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f1eebebf378 CR3: 000000006bb72000 CR4: 00000000003506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > > > > acpi_idle_enter+0xc5/0x160 drivers/acpi/processor_idle.c:702 > cpuidle_enter_state+0x85/0x500 drivers/cpuidle/cpuidle.c:267 > cpuidle_enter+0x4e/0xa0 drivers/cpuidle/cpuidle.c:388 > cpuidle_idle_call kernel/sched/idle.c:230 [inline] > do_idle+0x313/0x3f0 kernel/sched/idle.c:326 > cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:424 > rest_init+0x16b/0x2b0 init/main.c:747 > start_kernel+0x3df/0x4c0 init/main.c:1103 > x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507 > x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:488 > common_startup_64+0x13e/0x148 > > > > --- > 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 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