[v5.15] INFO: rcu detected stall in snd_rawmidi_write
0 views
Skip to first unread message
syzbot
Oct 17, 2025, 12:57:32 PM (16 hours ago) Oct 17
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: 29e53a5b1c4f Linux 5.15.194
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11c1b67c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e1bb6d24ef2164eb
dashboard link: https://syzkaller.appspot.com/bug?extid=61b8ea90ad701f9e2a82
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8cd4e3ff852c/disk-29e53a5b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/21e1f773622c/vmlinux-29e53a5b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8f418c0a25cc/bzImage-29e53a5b.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+61b8ea...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=3cf/1/0x4000000000000000 softirq=10254/10255 fqs=0
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9/1:b..l
(detected by 1, t=10502 jiffies, g=12393, q=5)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5451 Comm: syz.4.283 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:advance_sched+0x9d/0x940 net/sched/sch_taprio.c:717
Code: f9 85 db 0f 84 10 04 00 00 e8 8f 8a 6e f9 eb 05 e8 88 8a 6e f9 48 8d 5d e8 48 89 d8 48 c1 e8 03 48 89 44 24 58 42 80 3c 28 00 <74> 08 48 89 df e8 79 f2 b2 f9 48 89 5c 24 60 4c 8b 3b e8 4c f4 9f
RSP: 0018:ffffc90000007c80 EFLAGS: 00000046
RAX: 1ffff11003f6bc65 RBX: ffff88801fb5e328 RCX: ffff88802b2b0000
RDX: 0000000000010000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffff88801fb5e340 R08: 0000000000000004 R09: 0000000000000003
R10: fffff52000000f80 R11: 1ffff92000000f80 R12: ffff88801fb5e2e8
R13: dffffc0000000000 R14: ffff88801fb5e000 R15: 1ffff1100565615b
FS: 00007fc9cc91b6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001000 CR3: 0000000059f01000 CR4: 00000000003506f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
__run_hrtimer kernel/time/hrtimer.c:1685 [inline]
__hrtimer_run_queues+0x53d/0xc40 kernel/time/hrtimer.c:1749
hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
__sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:finish_lock_switch+0x134/0x280 kernel/sched/core.c:4804
Code: be ff ff ff ff e8 7c bd 55 08 85 c0 74 4a 4d 85 ff 75 66 e9 fe 00 00 00 48 89 df e8 36 28 5f 08 e8 a1 74 2a 00 fb 48 83 c4 08 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 48 89 df e8 d9 0f fe ff 43 80 3c
RSP: 0018:ffffc900032cf708 EFLAGS: 00000282
RAX: 8a9949e0afb7a300 RBX: ffff8880b903a340 RCX: 8a9949e0afb7a300
RDX: dffffc0000000000 RSI: ffffffff8a0b1820 RDI: ffffffff8a59a4c0
RBP: 1ffff11017207613 R08: dffffc0000000000 R09: ffffed1017207469
R10: ffffed1017207469 R11: 1ffff11017207468 R12: ffff8880b903b088
R13: dffffc0000000000 R14: ffff8880b903ae08 R15: 0000000000000000
finish_task_switch+0x12f/0x640 kernel/sched/core.c:4921
context_switch kernel/sched/core.c:5052 [inline]
__schedule+0x11c3/0x4390 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914
snd_rawmidi_write+0x3e3/0xbc0 sound/core/rawmidi.c:1542
do_loop_readv_writev fs/read_write.c:-1 [inline]
do_iter_write+0x3e4/0x7b0 fs/read_write.c:857
vfs_writev fs/read_write.c:928 [inline]
do_writev+0x254/0x410 fs/read_write.c:971
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fc9ce6b3fc9
Code: 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 01 48
RSP: 002b:00007fc9cc91b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007fc9ce90afa0 RCX: 00007fc9ce6b3fc9
RDX: 0000000000000002 RSI: 0000200000000840 RDI: 0000000000000008
RBP: 00007fc9ce736f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc9ce90b038 R14: 00007fc9ce90afa0 R15: 00007ffe90e8c878
</TASK>
task:kworker/u4:0 state:R running task stack:24008 pid: 9 ppid: 2 flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6799
irqentry_exit+0x63/0x70 kernel/entry/common.c:432
asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:681
RIP: 0010:rcu_read_unlock include/linux/rcupdate.h:768 [inline]
RIP: 0010:batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:416 [inline]
RIP: 0010:batadv_nc_worker+0x1ea/0x5c0 net/batman-adv/network-coding.c:723
Code: 62 f9 f7 e8 68 cc 2a 00 89 c5 31 ff 89 c6 e8 cd 65 f9 f7 85 ed 74 15 e8 84 47 e5 f7 84 c0 74 18 e8 5b 62 f9 f7 48 8b 6c 24 08 <eb> 65 e8 4f 62 f9 f7 48 8b 6c 24 08 eb 59 e8 33 cc 2a 00 89 c5 31
RSP: 0000:ffffc90000ce7be0 EFLAGS: 00000293
RAX: ffffffff897e67f5 RBX: dffffc0000000000 RCX: ffff88813fed0000
RDX: 0000000000000000 RSI: ffffffff8a59a4a0 RDI: ffffffff8a59a460
RBP: ffff888022c7ae00 R08: dffffc0000000000 R09: fffffbfff1ff7a19
R10: fffffbfff1ff7a19 R11: 1ffffffff1ff7a18 R12: 0000000000000301
R13: fffffffffffffe38 R14: ffff88801938cc80 R15: ffff888022c7ae10
process_one_work+0x863/0x1000 kernel/workqueue.c:2310
worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
rcu: rcu_preempt kthread starved for 10502 jiffies! g12393 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:27848 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914
rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972
rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 1
CPU: 1 PID: 5454 Comm: syz.4.283 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
<IRQ>
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
print_other_cpu_stall+0x10c8/0x1220 kernel/rcu/tree_stall.h:592
check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
rcu_pending kernel/rcu/tree.c:3936 [inline]
rcu_sched_clock_irq+0x831/0x1110 kernel/rcu/tree.c:2619
update_process_times+0x193/0x200 kernel/time/timer.c:1818
tick_sched_handle kernel/time/tick-sched.c:254 [inline]
tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
__run_hrtimer kernel/time/hrtimer.c:1685 [inline]
__hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1749
hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
__sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__sanitizer_cov_trace_pc+0x58/0x60 kernel/kcov.c:216
Code: 10 16 00 00 83 fa 02 75 21 48 8b 91 18 16 00 00 48 8b 32 48 8d 7e 01 8b 89 14 16 00 00 48 39 cf 73 08 48 89 44 f2 08 48 89 3a <c3> 0f 1f 80 00 00 00 00 48 8b 04 24 65 48 8b 0d 04 a5 8a 7e 65 8b
RSP: 0018:ffffc9000338fad8 EFLAGS: 00000246
RAX: ffffffff816c847b RBX: 0000000000000001 RCX: 0000000000080000
RDX: ffffc9000dfa9000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc9000338fc10 R08: dffffc0000000000 R09: ffffed101722767b
R10: ffffed101722767b R11: 1ffff1101722767a R12: ffff8880b9042848
R13: 1ffff11017208509 R14: ffff8880b913b3c0 R15: 0000000000000000
csd_lock_wait kernel/smp.c:440 [inline]
smp_call_function_many_cond+0xbab/0xd70 kernel/smp.c:969
clock_was_set+0x77e/0x840 kernel/time/hrtimer.c:959
do_settimeofday64+0x575/0x720 kernel/time/timekeeping.c:1328
__do_sys_clock_settime kernel/time/posix-timers.c:1125 [inline]
__se_sys_clock_settime kernel/time/posix-timers.c:1113 [inline]
__x64_sys_clock_settime+0x223/0x270 kernel/time/posix-timers.c:1113
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fc9ce6b3fc9
Code: 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 01 48
RSP: 002b:00007fc9cc8fa038 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3
RAX: ffffffffffffffda RBX: 00007fc9ce90b090 RCX: 00007fc9ce6b3fc9
RDX: 0000000000000000 RSI: 0000200000000240 RDI: 0000000000000000
RBP: 00007fc9ce736f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc9ce90b128 R14: 00007fc9ce90b090 R15: 00007ffe90e8c878
</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 syzk...@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
syzbot found the following issue on:
HEAD commit: 29e53a5b1c4f Linux 5.15.194
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11c1b67c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e1bb6d24ef2164eb
dashboard link: https://syzkaller.appspot.com/bug?extid=61b8ea90ad701f9e2a82
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8cd4e3ff852c/disk-29e53a5b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/21e1f773622c/vmlinux-29e53a5b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8f418c0a25cc/bzImage-29e53a5b.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+61b8ea...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=3cf/1/0x4000000000000000 softirq=10254/10255 fqs=0
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9/1:b..l
(detected by 1, t=10502 jiffies, g=12393, q=5)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5451 Comm: syz.4.283 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:advance_sched+0x9d/0x940 net/sched/sch_taprio.c:717
Code: f9 85 db 0f 84 10 04 00 00 e8 8f 8a 6e f9 eb 05 e8 88 8a 6e f9 48 8d 5d e8 48 89 d8 48 c1 e8 03 48 89 44 24 58 42 80 3c 28 00 <74> 08 48 89 df e8 79 f2 b2 f9 48 89 5c 24 60 4c 8b 3b e8 4c f4 9f
RSP: 0018:ffffc90000007c80 EFLAGS: 00000046
RAX: 1ffff11003f6bc65 RBX: ffff88801fb5e328 RCX: ffff88802b2b0000
RDX: 0000000000010000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffff88801fb5e340 R08: 0000000000000004 R09: 0000000000000003
R10: fffff52000000f80 R11: 1ffff92000000f80 R12: ffff88801fb5e2e8
R13: dffffc0000000000 R14: ffff88801fb5e000 R15: 1ffff1100565615b
FS: 00007fc9cc91b6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001000 CR3: 0000000059f01000 CR4: 00000000003506f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
__run_hrtimer kernel/time/hrtimer.c:1685 [inline]
__hrtimer_run_queues+0x53d/0xc40 kernel/time/hrtimer.c:1749
hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
__sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:finish_lock_switch+0x134/0x280 kernel/sched/core.c:4804
Code: be ff ff ff ff e8 7c bd 55 08 85 c0 74 4a 4d 85 ff 75 66 e9 fe 00 00 00 48 89 df e8 36 28 5f 08 e8 a1 74 2a 00 fb 48 83 c4 08 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 48 89 df e8 d9 0f fe ff 43 80 3c
RSP: 0018:ffffc900032cf708 EFLAGS: 00000282
RAX: 8a9949e0afb7a300 RBX: ffff8880b903a340 RCX: 8a9949e0afb7a300
RDX: dffffc0000000000 RSI: ffffffff8a0b1820 RDI: ffffffff8a59a4c0
RBP: 1ffff11017207613 R08: dffffc0000000000 R09: ffffed1017207469
R10: ffffed1017207469 R11: 1ffff11017207468 R12: ffff8880b903b088
R13: dffffc0000000000 R14: ffff8880b903ae08 R15: 0000000000000000
finish_task_switch+0x12f/0x640 kernel/sched/core.c:4921
context_switch kernel/sched/core.c:5052 [inline]
__schedule+0x11c3/0x4390 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914
snd_rawmidi_write+0x3e3/0xbc0 sound/core/rawmidi.c:1542
do_loop_readv_writev fs/read_write.c:-1 [inline]
do_iter_write+0x3e4/0x7b0 fs/read_write.c:857
vfs_writev fs/read_write.c:928 [inline]
do_writev+0x254/0x410 fs/read_write.c:971
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fc9ce6b3fc9
Code: 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 01 48
RSP: 002b:00007fc9cc91b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007fc9ce90afa0 RCX: 00007fc9ce6b3fc9
RDX: 0000000000000002 RSI: 0000200000000840 RDI: 0000000000000008
RBP: 00007fc9ce736f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc9ce90b038 R14: 00007fc9ce90afa0 R15: 00007ffe90e8c878
</TASK>
task:kworker/u4:0 state:R running task stack:24008 pid: 9 ppid: 2 flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6799
irqentry_exit+0x63/0x70 kernel/entry/common.c:432
asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:681
RIP: 0010:rcu_read_unlock include/linux/rcupdate.h:768 [inline]
RIP: 0010:batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:416 [inline]
RIP: 0010:batadv_nc_worker+0x1ea/0x5c0 net/batman-adv/network-coding.c:723
Code: 62 f9 f7 e8 68 cc 2a 00 89 c5 31 ff 89 c6 e8 cd 65 f9 f7 85 ed 74 15 e8 84 47 e5 f7 84 c0 74 18 e8 5b 62 f9 f7 48 8b 6c 24 08 <eb> 65 e8 4f 62 f9 f7 48 8b 6c 24 08 eb 59 e8 33 cc 2a 00 89 c5 31
RSP: 0000:ffffc90000ce7be0 EFLAGS: 00000293
RAX: ffffffff897e67f5 RBX: dffffc0000000000 RCX: ffff88813fed0000
RDX: 0000000000000000 RSI: ffffffff8a59a4a0 RDI: ffffffff8a59a460
RBP: ffff888022c7ae00 R08: dffffc0000000000 R09: fffffbfff1ff7a19
R10: fffffbfff1ff7a19 R11: 1ffffffff1ff7a18 R12: 0000000000000301
R13: fffffffffffffe38 R14: ffff88801938cc80 R15: ffff888022c7ae10
process_one_work+0x863/0x1000 kernel/workqueue.c:2310
worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
rcu: rcu_preempt kthread starved for 10502 jiffies! g12393 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:27848 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914
rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972
rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 1
CPU: 1 PID: 5454 Comm: syz.4.283 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
<IRQ>
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
print_other_cpu_stall+0x10c8/0x1220 kernel/rcu/tree_stall.h:592
check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
rcu_pending kernel/rcu/tree.c:3936 [inline]
rcu_sched_clock_irq+0x831/0x1110 kernel/rcu/tree.c:2619
update_process_times+0x193/0x200 kernel/time/timer.c:1818
tick_sched_handle kernel/time/tick-sched.c:254 [inline]
tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
__run_hrtimer kernel/time/hrtimer.c:1685 [inline]
__hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1749
hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
__sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__sanitizer_cov_trace_pc+0x58/0x60 kernel/kcov.c:216
Code: 10 16 00 00 83 fa 02 75 21 48 8b 91 18 16 00 00 48 8b 32 48 8d 7e 01 8b 89 14 16 00 00 48 39 cf 73 08 48 89 44 f2 08 48 89 3a <c3> 0f 1f 80 00 00 00 00 48 8b 04 24 65 48 8b 0d 04 a5 8a 7e 65 8b
RSP: 0018:ffffc9000338fad8 EFLAGS: 00000246
RAX: ffffffff816c847b RBX: 0000000000000001 RCX: 0000000000080000
RDX: ffffc9000dfa9000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc9000338fc10 R08: dffffc0000000000 R09: ffffed101722767b
R10: ffffed101722767b R11: 1ffff1101722767a R12: ffff8880b9042848
R13: 1ffff11017208509 R14: ffff8880b913b3c0 R15: 0000000000000000
csd_lock_wait kernel/smp.c:440 [inline]
smp_call_function_many_cond+0xbab/0xd70 kernel/smp.c:969
clock_was_set+0x77e/0x840 kernel/time/hrtimer.c:959
do_settimeofday64+0x575/0x720 kernel/time/timekeeping.c:1328
__do_sys_clock_settime kernel/time/posix-timers.c:1125 [inline]
__se_sys_clock_settime kernel/time/posix-timers.c:1113 [inline]
__x64_sys_clock_settime+0x223/0x270 kernel/time/posix-timers.c:1113
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fc9ce6b3fc9
Code: 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 01 48
RSP: 002b:00007fc9cc8fa038 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3
RAX: ffffffffffffffda RBX: 00007fc9ce90b090 RCX: 00007fc9ce6b3fc9
RDX: 0000000000000000 RSI: 0000200000000240 RDI: 0000000000000000
RBP: 00007fc9ce736f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc9ce90b128 R14: 00007fc9ce90b090 R15: 00007ffe90e8c878
</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 syzk...@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
Reply all
Reply to author
Forward
0 new messages