[v5.15] INFO: rcu detected stall in clone3 (3)
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syzbot
Jul 10, 2026, 12:09:29 AM (3 days ago) Jul 10
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: c86c4726e7f0 Linux 5.15.211
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=16c13389580000
kernel config: https://syzkaller.appspot.com/x/.config?x=6f8e2266b61925dc
dashboard link: https://syzkaller.appspot.com/bug?extid=d2f8d9990c9a9fb93118
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c3e980557785/disk-c86c4726.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5fbaf3714ad0/vmlinux-c86c4726.xz
kernel image: https://storage.googleapis.com/syzbot-assets/de60a4f1e940/bzImage-c86c4726.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d2f8d9...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P19821/1:b..l
(detected by 0, t=10502 jiffies, g=102645, q=4)
task:kworker/u4:7 state:R running task stack:22640 pid:19821 ppid: 2 flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
preempt_schedule_irq+0xbb/0x160 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_lock include/linux/rcupdate.h:741 [inline]
RIP: 0010:batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline]
RIP: 0010:batadv_nc_worker+0xd4/0x5c0 net/batman-adv/network-coding.c:723
Code: 08 48 89 ef e8 2d 5d 2a f8 4e 8d 2c e5 00 00 00 00 4c 03 6d 00 e8 6c 97 d1 f7 e8 27 7b 00 00 e8 22 68 2b 00 89 c5 31 ff 89 c6 <e8> e7 41 e5 f7 85 ed 74 10 e8 5e e9 d0 f7 84 c0 74 0e e8 75 3e e5
RSP: 0018:ffffc900032dfbe0 EFLAGS: 00000246
RAX: 0000000000000001 RBX: dffffc0000000000 RCX: ffff888066b21dc0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff203d218
R10: dffffc0000000000 R11: fffffbfff203d219 R12: 0000000000000009
R13: ffff888017dac048 R14: ffff8880788f8c80 R15: ffff88802a6e5dd0
process_one_work+0x867/0xff0 kernel/workqueue.c:2310
worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
kthread+0x42e/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! g102645 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:28112 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117
rcu_gp_fqs_loop+0x2be/0x11f0 kernel/rcu/tree.c:1972
rcu_gp_kthread+0x9a/0x370 kernel/rcu/tree.c:2145
kthread+0x42e/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:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 27410 Comm: syz.3.5957 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:__run_hrtimer kernel/time/hrtimer.c:1683 [inline]
RIP: 0010:__hrtimer_run_queues+0x4b5/0xb60 kernel/time/hrtimer.c:1749
Code: 04 38 84 c0 0f 85 d0 02 00 00 0f b6 1b 31 ff 89 de e8 1f 45 10 00 85 db 74 10 e8 b6 42 10 00 4c 89 ef 41 ff d4 41 89 c4 eb 4c <e8> a6 42 10 00 65 4c 8b 35 be bf 99 7e 49 81 c6 d8 0a 00 00 4c 89
RSP: 0018:ffffc90000dd0d60 EFLAGS: 00000046
RAX: ffffffff8168afe1 RBX: 0000000000000000 RCX: ffff88804a1d9dc0
RDX: 0000000000010000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000dd0ec0 R08: ffffffff8d8aeaef R09: 1ffffffff1b15d5d
R10: dffffc0000000000 R11: fffffbfff1b15d5e R12: ffffffff8819bdb0
R13: ffff88805ceb1340 R14: 0000000000000001 R15: dffffc0000000000
FS: 00005555626b0500(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe5358e5d58 CR3: 000000002e426000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
hrtimer_interrupt+0x397/0x8b0 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:instrument_write include/linux/instrumented.h:41 [inline]
RIP: 0010:__set_bit include/asm-generic/bitops/instrumented-non-atomic.h:27 [inline]
RIP: 0010:__set_page_owner_handle mm/page_owner.c:166 [inline]
RIP: 0010:__set_page_owner+0x1a6/0x2d0 mm/page_owner.c:182
Code: 89 e8 48 c1 e8 03 80 3c 18 00 74 08 4c 89 ef e8 20 a9 f9 ff 4d 89 65 00 4c 89 f7 be 08 00 00 00 e8 2f aa f9 ff 49 0f ba 2e 00 <4c> 89 f7 be 08 00 00 00 e8 1d aa f9 ff 49 0f ba 2e 01 48 8b 44 24
RSP: 0018:ffffc900043cf250 EFLAGS: 00000257
RAX: 1ffff11003366901 RBX: dffffc0000000000 RCX: ffffffff81c46891
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff888019b34d60
RBP: 0000000000100cc0 R08: ffff888019b34d67 R09: 1ffff110033669ac
R10: dffffc0000000000 R11: ffffed10033669ad R12: 00000160886cba65
R13: ffff888019b34d78 R14: ffff888019b34d60 R15: 0000000000000000
prep_new_page mm/page_alloc.c:2426 [inline]
get_page_from_freelist+0x24f6/0x2670 mm/page_alloc.c:4192
__alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501
__get_free_pages+0x8/0x30 mm/page_alloc.c:5538
kasan_populate_vmalloc_pte+0x21/0xc0 mm/kasan/shadow.c:266
apply_to_pte_range mm/memory.c:2573 [inline]
apply_to_pmd_range mm/memory.c:2617 [inline]
apply_to_pud_range mm/memory.c:2653 [inline]
apply_to_p4d_range mm/memory.c:2689 [inline]
__apply_to_page_range+0x987/0xd10 mm/memory.c:2725
alloc_vmap_area+0x19e8/0x1b30 mm/vmalloc.c:1572
__get_vm_area_node+0x14f/0x2d0 mm/vmalloc.c:2430
__vmalloc_node_range+0xef/0x8b0 mm/vmalloc.c:3027
alloc_thread_stack_node kernel/fork.c:247 [inline]
dup_task_struct+0x41a/0xb70 kernel/fork.c:900
copy_process+0x61f/0x3ec0 kernel/fork.c:2122
kernel_clone+0x23f/0x990 kernel/fork.c:2681
__do_sys_clone3 kernel/fork.c:2956 [inline]
__se_sys_clone3+0x312/0x3d0 kernel/fork.c:2940
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: 0033:0x7fe5376cfc49
Code: 90 b8 01 00 00 00 b9 01 00 00 00 eb ec 0f 1f 40 00 b8 ea ff ff ff 48 85 ff 74 28 48 85 d2 74 23 49 89 c8 b8 b3 01 00 00 0f 05 <48> 85 c0 7c 14 74 01 c3 31 ed 4c 89 c7 ff d2 48 89 c7 b8 3c 00 00
RSP: 002b:00007ffcaeae7278 EFLAGS: 00000202 ORIG_RAX: 00000000000001b3
RAX: ffffffffffffffda RBX: 00007fe53768b1e0 RCX: 00007fe5376cfc49
RDX: 00007fe53768b1e0 RSI: 0000000000000058 RDI: 00007ffcaeae72d0
RBP: 00007fe5358e56c0 R08: 00007fe5358e56c0 R09: 00007ffcaeae73b7
R10: 0000000000000008 R11: 0000000000000202 R12: ffffffffffffffe8
R13: 000000000000006e R14: 00007ffcaeae72d0 R15: 00007ffcaeae73b8
</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: c86c4726e7f0 Linux 5.15.211
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=16c13389580000
kernel config: https://syzkaller.appspot.com/x/.config?x=6f8e2266b61925dc
dashboard link: https://syzkaller.appspot.com/bug?extid=d2f8d9990c9a9fb93118
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c3e980557785/disk-c86c4726.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5fbaf3714ad0/vmlinux-c86c4726.xz
kernel image: https://storage.googleapis.com/syzbot-assets/de60a4f1e940/bzImage-c86c4726.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d2f8d9...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P19821/1:b..l
(detected by 0, t=10502 jiffies, g=102645, q=4)
task:kworker/u4:7 state:R running task stack:22640 pid:19821 ppid: 2 flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
preempt_schedule_irq+0xbb/0x160 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_lock include/linux/rcupdate.h:741 [inline]
RIP: 0010:batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline]
RIP: 0010:batadv_nc_worker+0xd4/0x5c0 net/batman-adv/network-coding.c:723
Code: 08 48 89 ef e8 2d 5d 2a f8 4e 8d 2c e5 00 00 00 00 4c 03 6d 00 e8 6c 97 d1 f7 e8 27 7b 00 00 e8 22 68 2b 00 89 c5 31 ff 89 c6 <e8> e7 41 e5 f7 85 ed 74 10 e8 5e e9 d0 f7 84 c0 74 0e e8 75 3e e5
RSP: 0018:ffffc900032dfbe0 EFLAGS: 00000246
RAX: 0000000000000001 RBX: dffffc0000000000 RCX: ffff888066b21dc0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff203d218
R10: dffffc0000000000 R11: fffffbfff203d219 R12: 0000000000000009
R13: ffff888017dac048 R14: ffff8880788f8c80 R15: ffff88802a6e5dd0
process_one_work+0x867/0xff0 kernel/workqueue.c:2310
worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
kthread+0x42e/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! g102645 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:28112 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117
rcu_gp_fqs_loop+0x2be/0x11f0 kernel/rcu/tree.c:1972
rcu_gp_kthread+0x9a/0x370 kernel/rcu/tree.c:2145
kthread+0x42e/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:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 27410 Comm: syz.3.5957 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:__run_hrtimer kernel/time/hrtimer.c:1683 [inline]
RIP: 0010:__hrtimer_run_queues+0x4b5/0xb60 kernel/time/hrtimer.c:1749
Code: 04 38 84 c0 0f 85 d0 02 00 00 0f b6 1b 31 ff 89 de e8 1f 45 10 00 85 db 74 10 e8 b6 42 10 00 4c 89 ef 41 ff d4 41 89 c4 eb 4c <e8> a6 42 10 00 65 4c 8b 35 be bf 99 7e 49 81 c6 d8 0a 00 00 4c 89
RSP: 0018:ffffc90000dd0d60 EFLAGS: 00000046
RAX: ffffffff8168afe1 RBX: 0000000000000000 RCX: ffff88804a1d9dc0
RDX: 0000000000010000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000dd0ec0 R08: ffffffff8d8aeaef R09: 1ffffffff1b15d5d
R10: dffffc0000000000 R11: fffffbfff1b15d5e R12: ffffffff8819bdb0
R13: ffff88805ceb1340 R14: 0000000000000001 R15: dffffc0000000000
FS: 00005555626b0500(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe5358e5d58 CR3: 000000002e426000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
hrtimer_interrupt+0x397/0x8b0 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:instrument_write include/linux/instrumented.h:41 [inline]
RIP: 0010:__set_bit include/asm-generic/bitops/instrumented-non-atomic.h:27 [inline]
RIP: 0010:__set_page_owner_handle mm/page_owner.c:166 [inline]
RIP: 0010:__set_page_owner+0x1a6/0x2d0 mm/page_owner.c:182
Code: 89 e8 48 c1 e8 03 80 3c 18 00 74 08 4c 89 ef e8 20 a9 f9 ff 4d 89 65 00 4c 89 f7 be 08 00 00 00 e8 2f aa f9 ff 49 0f ba 2e 00 <4c> 89 f7 be 08 00 00 00 e8 1d aa f9 ff 49 0f ba 2e 01 48 8b 44 24
RSP: 0018:ffffc900043cf250 EFLAGS: 00000257
RAX: 1ffff11003366901 RBX: dffffc0000000000 RCX: ffffffff81c46891
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff888019b34d60
RBP: 0000000000100cc0 R08: ffff888019b34d67 R09: 1ffff110033669ac
R10: dffffc0000000000 R11: ffffed10033669ad R12: 00000160886cba65
R13: ffff888019b34d78 R14: ffff888019b34d60 R15: 0000000000000000
prep_new_page mm/page_alloc.c:2426 [inline]
get_page_from_freelist+0x24f6/0x2670 mm/page_alloc.c:4192
__alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501
__get_free_pages+0x8/0x30 mm/page_alloc.c:5538
kasan_populate_vmalloc_pte+0x21/0xc0 mm/kasan/shadow.c:266
apply_to_pte_range mm/memory.c:2573 [inline]
apply_to_pmd_range mm/memory.c:2617 [inline]
apply_to_pud_range mm/memory.c:2653 [inline]
apply_to_p4d_range mm/memory.c:2689 [inline]
__apply_to_page_range+0x987/0xd10 mm/memory.c:2725
alloc_vmap_area+0x19e8/0x1b30 mm/vmalloc.c:1572
__get_vm_area_node+0x14f/0x2d0 mm/vmalloc.c:2430
__vmalloc_node_range+0xef/0x8b0 mm/vmalloc.c:3027
alloc_thread_stack_node kernel/fork.c:247 [inline]
dup_task_struct+0x41a/0xb70 kernel/fork.c:900
copy_process+0x61f/0x3ec0 kernel/fork.c:2122
kernel_clone+0x23f/0x990 kernel/fork.c:2681
__do_sys_clone3 kernel/fork.c:2956 [inline]
__se_sys_clone3+0x312/0x3d0 kernel/fork.c:2940
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: 0033:0x7fe5376cfc49
Code: 90 b8 01 00 00 00 b9 01 00 00 00 eb ec 0f 1f 40 00 b8 ea ff ff ff 48 85 ff 74 28 48 85 d2 74 23 49 89 c8 b8 b3 01 00 00 0f 05 <48> 85 c0 7c 14 74 01 c3 31 ed 4c 89 c7 ff d2 48 89 c7 b8 3c 00 00
RSP: 002b:00007ffcaeae7278 EFLAGS: 00000202 ORIG_RAX: 00000000000001b3
RAX: ffffffffffffffda RBX: 00007fe53768b1e0 RCX: 00007fe5376cfc49
RDX: 00007fe53768b1e0 RSI: 0000000000000058 RDI: 00007ffcaeae72d0
RBP: 00007fe5358e56c0 R08: 00007fe5358e56c0 R09: 00007ffcaeae73b7
R10: 0000000000000008 R11: 0000000000000202 R12: ffffffffffffffe8
R13: 000000000000006e R14: 00007ffcaeae72d0 R15: 00007ffcaeae73b8
</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
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