From: syzbot <syzbot+6d991f16f4bcc8eeea24@syzkaller.appspotmail.com>
To: anna-maria@linutronix.de, frederic@kernel.org,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
syzkaller-bugs@googlegroups.com, tglx@kernel.org
Subject: Re: [syzbot] [kernel?] INFO: rcu detected stall in __hrtimer_run_queues (3)
Date: Mon, 31 Aug 2026 08:55:30 -0700 [thread overview]
Message-ID: <6a95a3f2.99925153.16bd3d.0004.GAE@google.com> (raw)
In-Reply-To: <6a778cfc.9c11d2ce.289b96.00b9.GAE@google.com>
syzbot has found a reproducer for the following issue on:
HEAD commit: f1b8fa82cab7 Merge branch 'for-next/core' into for-kernelci
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=15aee379580000
kernel config: https://syzkaller.appspot.com/x/.config?x=d1128bc53f2ef7f3
dashboard link: https://syzkaller.appspot.com/bug?extid=6d991f16f4bcc8eeea24
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15632d9e580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15dd1c15580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/932d85a2bda2/disk-f1b8fa82.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5b6b8fb76e8d/vmlinux-f1b8fa82.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c246b61ee396/Image-f1b8fa82.gz.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6d991f16f4bcc8eeea24@syzkaller.appspotmail.com
watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [syz-executor:4831]
Modules linked in:
irq event stamp: 38640849
hardirqs last enabled at (38640848): [<ffff800080557cd8>] seqcount_lockdep_reader_access+0x7c/0xf8 include/linux/seqlock.h:75
hardirqs last disabled at (38640849): [<ffff80008690cd0c>] __el1_irq arch/arm64/kernel/entry-common.c:527 [inline]
hardirqs last disabled at (38640849): [<ffff80008690cd0c>] el1_interrupt+0x28/0x60 arch/arm64/kernel/entry-common.c:543
softirqs last enabled at (147672): [<ffff80008013891c>] local_bh_enable include/linux/bottom_half.h:33 [inline]
softirqs last enabled at (147672): [<ffff80008013891c>] put_cpu_fpsimd_context arch/arm64/kernel/fpsimd.c:251 [inline]
softirqs last enabled at (147672): [<ffff80008013891c>] do_sve_acc+0x32c/0x4b8 arch/arm64/kernel/fpsimd.c:1349
softirqs last disabled at (148217): [<ffff8000800204c0>] __do_softirq+0x14/0x20 kernel/softirq.c:656
CPU: 0 UID: 0 PID: 4831 Comm: syz-executor Not tainted syzkaller #0 PREEMPT
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/07/2026
pstate: 43400005 (nZcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : trace_hrtimer_expire_exit include/trace/events/timer.h:321 [inline]
pc : __run_hrtimer kernel/time/hrtimer.c:2035 [inline]
pc : __hrtimer_run_queues+0x32c/0xbe0 kernel/time/hrtimer.c:2096
lr : arch_static_branch arch/arm64/include/asm/jump_label.h:36 [inline]
lr : trace_hrtimer_expire_exit include/trace/events/timer.h:321 [inline]
lr : __run_hrtimer kernel/time/hrtimer.c:2035 [inline]
lr : __hrtimer_run_queues+0x32c/0xbe0 kernel/time/hrtimer.c:2096
sp : ffff80008eb67de0
x29: ffff80008eb67e40 x28: 1fffe00034bb7c3a x27: ffff0001a5dbe1c0
x26: ffff0000c6453a90 x25: ffff0000d1a50d38 x24: dfff800000000000
x23: 0000000000000001 x22: ffff800084ec6bd4 x21: 1fffe00018c8a752
x20: ffff0000c64545a8 x19: ffff0000c6453a80 x18: 0000000000000000
x17: ffff80011d2d8000 x16: ffff80008eb60000 x15: 0000000000000000
x14: 00000000ffff8000 x13: 0000000000000001 x12: 0000000000000000
x11: 0000000000000000 x10: 0000000000000102 x9 : 0000000000000101
x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000
x5 : 0000000000000001 x4 : 0000000000000008 x3 : ffff80008046a634
x2 : 0000000000000001 x1 : ffff0000c6453a80 x0 : 0000000000000000
Call trace:
arch_static_branch arch/arm64/include/asm/jump_label.h:36 [inline] (P)
trace_hrtimer_expire_exit include/trace/events/timer.h:321 [inline] (P)
__run_hrtimer kernel/time/hrtimer.c:2035 [inline] (P)
__hrtimer_run_queues+0x32c/0xbe0 kernel/time/hrtimer.c:2096 (P)
hrtimer_run_softirq+0x15c/0x21c kernel/time/hrtimer.c:2113
handle_softirqs+0x2ec/0xd98 kernel/softirq.c:622
__do_softirq+0x14/0x20 kernel/softirq.c:656
____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:78
call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:885
do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:83
invoke_softirq kernel/softirq.c:503 [inline]
__irq_exit_rcu+0x1ac/0x428 kernel/softirq.c:735
irq_exit_rcu+0x14/0x84 kernel/softirq.c:752
__el1_irq arch/arm64/kernel/entry-common.c:531 [inline]
el1_interrupt+0x40/0x60 arch/arm64/kernel/entry-common.c:543
el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:548
el1h_64_irq+0x6c/0x70 arch/arm64/kernel/entry.S:586
__daif_local_irq_restore arch/arm64/include/asm/irqflags.h:175 [inline] (P)
arch_local_irq_restore arch/arm64/include/asm/irqflags.h:195 [inline] (P)
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:178 [inline] (P)
_raw_spin_unlock_irqrestore+0x44/0x98 kernel/locking/spinlock.c:198 (P)
__debug_check_no_obj_freed lib/debugobjects.c:1180 [inline]
debug_check_no_obj_freed+0x2c8/0x3a4 lib/debugobjects.c:1201
slab_free_hook mm/slub.c:2608 [inline]
slab_free mm/slub.c:6377 [inline]
kmem_cache_free+0x120/0x6b8 mm/slub.c:6504
file_free+0x128/0x1dc fs/file_table.c:104
__fput+0x538/0x74c fs/file_table.c:525
fput_close_sync+0x10c/0x278 fs/file_table.c:617
__do_sys_close fs/open.c:1511 [inline]
__se_sys_close fs/open.c:1496 [inline]
__arm64_sys_close+0x80/0x110 fs/open.c:1496
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:758
el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:777
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 4802 Comm: kworker/1:3 Not tainted syzkaller #0 PREEMPT
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/07/2026
Workqueue: rcu_gp process_srcu
pstate: 83400005 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline]
pc : _raw_spin_unlock_irqrestore+0x44/0x98 kernel/locking/spinlock.c:198
lr : __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:178 [inline]
lr : _raw_spin_unlock_irqrestore+0x38/0x98 kernel/locking/spinlock.c:198
sp : ffff80008eb77dc0
x29: ffff80008eb77dc0 x28: 1fffe00034bbc63a x27: ffff0001a5de31c0
x26: ffff0001a5de31d0 x25: ffff0000d2a4a538 x24: dfff800000000000
x23: 0000000000000001 x22: ffff800084ec6bd4 x21: ffff0001a5de2d80
x20: ffff0001a5de2d80 x19: 0000000000000000 x18: 00000000ffffffff
x17: ffff80008a7d6000 x16: 0000000000000002 x15: ffff80008a35fda0
x14: ffff80008a5d5e28 x13: 0000000000000001 x12: 0000000000000000
x11: ffff80008a5d5e28 x10: 0000000000000003 x9 : 0000000000000000
x8 : 00000000000000c0 x7 : 0000000000000000 x6 : 0000000000000000
x5 : 0000000000000001 x4 : 0000000000000008 x3 : ffff80008015611c
x2 : 0000000000000002 x1 : ffff0000d32c9d40 x0 : ffff80011d2fd000
Call trace:
__daif_local_irq_restore arch/arm64/include/asm/irqflags.h:175 [inline] (P)
arch_local_irq_restore arch/arm64/include/asm/irqflags.h:195 [inline] (P)
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:178 [inline] (P)
_raw_spin_unlock_irqrestore+0x44/0x98 kernel/locking/spinlock.c:198 (P)
__run_hrtimer kernel/time/hrtimer.c:2028 [inline]
__hrtimer_run_queues+0x22c/0xbe0 kernel/time/hrtimer.c:2096
hrtimer_run_softirq+0x15c/0x21c kernel/time/hrtimer.c:2113
handle_softirqs+0x2ec/0xd98 kernel/softirq.c:622
__do_softirq+0x14/0x20 kernel/softirq.c:656
____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:78
call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:885
do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:83
invoke_softirq kernel/softirq.c:503 [inline]
__irq_exit_rcu+0x1ac/0x428 kernel/softirq.c:735
irq_exit_rcu+0x14/0x84 kernel/softirq.c:752
__el1_irq arch/arm64/kernel/entry-common.c:531 [inline]
el1_interrupt+0x40/0x60 arch/arm64/kernel/entry-common.c:543
el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:548
el1h_64_irq+0x6c/0x70 arch/arm64/kernel/entry.S:586
__daif_local_irq_restore arch/arm64/include/asm/irqflags.h:175 [inline] (P)
arch_local_irq_restore arch/arm64/include/asm/irqflags.h:195 [inline] (P)
queue_delayed_work_on+0xf4/0x140 kernel/workqueue.c:2624 (P)
queue_delayed_work include/linux/workqueue.h:714 [inline]
srcu_reschedule+0x240/0x338 kernel/rcu/srcutree.c:1957
process_srcu+0xd04/0x1eb8 kernel/rcu/srcutree.c:1991
process_one_work kernel/workqueue.c:3322 [inline]
process_scheduled_works+0x788/0x10b8 kernel/workqueue.c:3405
worker_thread+0x798/0xbd0 kernel/workqueue.c:3486
kthread+0x304/0x3d4 kernel/kthread.c:436
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:838
watchdog: BUG: soft lockup - CPU#1 stuck for 26s! [kworker/1:3:4802]
Modules linked in:
irq event stamp: 44430735
hardirqs last enabled at (44430734): [<ffff800086932074>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:178 [inline]
hardirqs last enabled at (44430734): [<ffff800086932074>] _raw_spin_unlock_irqrestore+0x38/0x98 kernel/locking/spinlock.c:198
hardirqs last disabled at (44430735): [<ffff80008690cd0c>] __el1_irq arch/arm64/kernel/entry-common.c:527 [inline]
hardirqs last disabled at (44430735): [<ffff80008690cd0c>] el1_interrupt+0x28/0x60 arch/arm64/kernel/entry-common.c:543
softirqs last enabled at (6136): [<ffff80008030e6e4>] softirq_handle_end kernel/softirq.c:468 [inline]
softirqs last enabled at (6136): [<ffff80008030e6e4>] handle_softirqs+0xc28/0xd98 kernel/softirq.c:650
softirqs last disabled at (7461): [<ffff8000800204c0>] __do_softirq+0x14/0x20 kernel/softirq.c:656
---
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.
next prev parent reply other threads:[~2026-08-31 15:55 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-08 20:09 syzbot
2026-08-31 15:55 ` syzbot [this message]
2026-09-04 5:00 ` Thomas Gleixner
2026-09-04 13:51 ` Aleksandr Nogikh
2026-09-04 22:32 ` Thomas Gleixner
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