[v6.6] INFO: rcu detected stall in do_idle
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syzbot
Jun 23, 2025, 9:25:29 PM6/23/25
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: 6282921b6825 Linux 6.6.94
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=165a7b0c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=96da6b2210cda427
dashboard link: https://syzkaller.appspot.com/bug?extid=1d0ebb5530b0023d4b6b
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a3bf0d8e22b2/disk-6282921b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d1d442f782d0/vmlinux-6282921b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a8378f4b7e1b/bzImage-6282921b.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1d0ebb...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7172/1:b..l
rcu: (detected by 1, t=10503 jiffies, g=15641, q=80 ncpus=2)
task:syz.0.283 state:R running task stack:25608 pid:7172 ppid:5764 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x14e2/0x4580 kernel/sched/core.c:6700
preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867
preempt_schedule+0xab/0xc0 kernel/sched/core.c:6891
preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
__raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
_raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
zap_pte_range mm/memory.c:1522 [inline]
zap_pmd_range mm/memory.c:1570 [inline]
zap_pud_range mm/memory.c:1599 [inline]
zap_p4d_range mm/memory.c:1620 [inline]
unmap_page_range+0x236f/0x2fe0 mm/memory.c:1641
unmap_vmas+0x25e/0x3a0 mm/memory.c:1731
exit_mmap+0x200/0xb50 mm/mmap.c:3292
__mmput+0x118/0x3c0 kernel/fork.c:1355
exit_mm+0x1da/0x2c0 kernel/exit.c:569
do_exit+0x886/0x23c0 kernel/exit.c:861
do_group_exit+0x21b/0x2d0 kernel/exit.c:1023
get_signal+0x12fc/0x1400 kernel/signal.c:2902
arch_do_signal_or_restart+0x96/0x780 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f3a4998e929
RSP: 002b:00007f3a4a7b30e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f3a49bb6088 RCX: 00007f3a4998e929
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f3a49bb6088
RBP: 00007f3a49bb6080 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3a49bb608c
R13: 0000000000000000 R14: 00007fff7efcb1a0 R15: 00007fff7efcb288
</TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10502 jiffies! g15641 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=15126
rcu: rcu_preempt kthread starved for 10503 jiffies! g15641 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27496 pid:17 ppid:2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x14e2/0x4580 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
schedule_timeout+0x160/0x280 kernel/time/timer.c:2167
rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</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 PID: 0 Comm: swapper/0 Not tainted 6.6.94-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:trace_lock_release include/trace/events/lock.h:69 [inline]
RIP: 0010:lock_release+0xb3/0x8b0 kernel/locking/lockdep.c:5765
Code: 9c 7e 83 f8 08 0f 83 24 05 00 00 89 c3 c1 e8 06 48 8d 3c c5 28 ab 49 8e be 08 00 00 00 e8 85 c3 76 00 48 0f a3 1d f5 2f e2 0c <73> 0d e8 26 15 08 00 84 c0 0f 84 2c 05 00 00 48 c7 c0 dc df 49 8e
RSP: 0018:ffffc90000007b40 EFLAGS: 00000057
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff81677b2b
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e49ab28
RBP: ffffc90000007c60 R08: ffffffff8e49ab2f R09: 1ffffffff1c93565
R10: dffffc0000000000 R11: fffffbfff1c93566 R12: ffffffff88954949
R13: dffffc0000000000 R14: 18535bd6fc000000 R15: 1ffff92000000f74
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f58f074d550 CR3: 0000000063eac000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
rcu_lock_release include/linux/rcupdate.h:344 [inline]
rcu_read_unlock include/linux/rcupdate.h:819 [inline]
advance_sched+0xb29/0xc80 net/sched/sch_taprio.c:998
__run_hrtimer kernel/time/hrtimer.c:1755 [inline]
__hrtimer_run_queues+0x51e/0xc40 kernel/time/hrtimer.c:1819
hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1881
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
__sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:148
Code: cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d 63 f0 41 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 66 0f 1f 00 55 41 57 41 56
RSP: 0018:ffffffff8ca07d80 EFLAGS: 000002c2
RAX: 18da0511c23bf800 RBX: ffffffff81618a7b RCX: 18da0511c23bf800
RDX: 0000000000000001 RSI: ffffffff8aaab2c0 RDI: ffffffff8afc6900
RBP: ffffffff8ca07eb8 R08: ffff8880b8e36d4b R09: 1ffff110171c6da9
R10: dffffc0000000000 R11: ffffed10171c6daa R12: ffffffff8e49ab28
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1952670
arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:753
default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97
cpuidle_idle_call kernel/sched/idle.c:170 [inline]
do_idle+0x1eb/0x510 kernel/sched/idle.c:282
cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380
rest_init+0x2e2/0x300 init/main.c:732
arch_call_rest_init+0xe/0x10 init/main.c:829
start_kernel+0x459/0x4e0 init/main.c:1074
x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555
x86_64_start_kernel+0x60/0x60 arch/x86/kernel/head64.c:536
secondary_startup_64_no_verify+0x179/0x17b
</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: 6282921b6825 Linux 6.6.94
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=165a7b0c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=96da6b2210cda427
dashboard link: https://syzkaller.appspot.com/bug?extid=1d0ebb5530b0023d4b6b
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a3bf0d8e22b2/disk-6282921b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d1d442f782d0/vmlinux-6282921b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a8378f4b7e1b/bzImage-6282921b.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1d0ebb...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7172/1:b..l
rcu: (detected by 1, t=10503 jiffies, g=15641, q=80 ncpus=2)
task:syz.0.283 state:R running task stack:25608 pid:7172 ppid:5764 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x14e2/0x4580 kernel/sched/core.c:6700
preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867
preempt_schedule+0xab/0xc0 kernel/sched/core.c:6891
preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
__raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
_raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
zap_pte_range mm/memory.c:1522 [inline]
zap_pmd_range mm/memory.c:1570 [inline]
zap_pud_range mm/memory.c:1599 [inline]
zap_p4d_range mm/memory.c:1620 [inline]
unmap_page_range+0x236f/0x2fe0 mm/memory.c:1641
unmap_vmas+0x25e/0x3a0 mm/memory.c:1731
exit_mmap+0x200/0xb50 mm/mmap.c:3292
__mmput+0x118/0x3c0 kernel/fork.c:1355
exit_mm+0x1da/0x2c0 kernel/exit.c:569
do_exit+0x886/0x23c0 kernel/exit.c:861
do_group_exit+0x21b/0x2d0 kernel/exit.c:1023
get_signal+0x12fc/0x1400 kernel/signal.c:2902
arch_do_signal_or_restart+0x96/0x780 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f3a4998e929
RSP: 002b:00007f3a4a7b30e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f3a49bb6088 RCX: 00007f3a4998e929
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f3a49bb6088
RBP: 00007f3a49bb6080 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3a49bb608c
R13: 0000000000000000 R14: 00007fff7efcb1a0 R15: 00007fff7efcb288
</TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10502 jiffies! g15641 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=15126
rcu: rcu_preempt kthread starved for 10503 jiffies! g15641 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27496 pid:17 ppid:2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x14e2/0x4580 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
schedule_timeout+0x160/0x280 kernel/time/timer.c:2167
rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</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 PID: 0 Comm: swapper/0 Not tainted 6.6.94-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:trace_lock_release include/trace/events/lock.h:69 [inline]
RIP: 0010:lock_release+0xb3/0x8b0 kernel/locking/lockdep.c:5765
Code: 9c 7e 83 f8 08 0f 83 24 05 00 00 89 c3 c1 e8 06 48 8d 3c c5 28 ab 49 8e be 08 00 00 00 e8 85 c3 76 00 48 0f a3 1d f5 2f e2 0c <73> 0d e8 26 15 08 00 84 c0 0f 84 2c 05 00 00 48 c7 c0 dc df 49 8e
RSP: 0018:ffffc90000007b40 EFLAGS: 00000057
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff81677b2b
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e49ab28
RBP: ffffc90000007c60 R08: ffffffff8e49ab2f R09: 1ffffffff1c93565
R10: dffffc0000000000 R11: fffffbfff1c93566 R12: ffffffff88954949
R13: dffffc0000000000 R14: 18535bd6fc000000 R15: 1ffff92000000f74
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f58f074d550 CR3: 0000000063eac000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
rcu_lock_release include/linux/rcupdate.h:344 [inline]
rcu_read_unlock include/linux/rcupdate.h:819 [inline]
advance_sched+0xb29/0xc80 net/sched/sch_taprio.c:998
__run_hrtimer kernel/time/hrtimer.c:1755 [inline]
__hrtimer_run_queues+0x51e/0xc40 kernel/time/hrtimer.c:1819
hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1881
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
__sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:148
Code: cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d 63 f0 41 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 66 0f 1f 00 55 41 57 41 56
RSP: 0018:ffffffff8ca07d80 EFLAGS: 000002c2
RAX: 18da0511c23bf800 RBX: ffffffff81618a7b RCX: 18da0511c23bf800
RDX: 0000000000000001 RSI: ffffffff8aaab2c0 RDI: ffffffff8afc6900
RBP: ffffffff8ca07eb8 R08: ffff8880b8e36d4b R09: 1ffff110171c6da9
R10: dffffc0000000000 R11: ffffed10171c6daa R12: ffffffff8e49ab28
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1952670
arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:753
default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97
cpuidle_idle_call kernel/sched/idle.c:170 [inline]
do_idle+0x1eb/0x510 kernel/sched/idle.c:282
cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380
rest_init+0x2e2/0x300 init/main.c:732
arch_call_rest_init+0xe/0x10 init/main.c:829
start_kernel+0x459/0x4e0 init/main.c:1074
x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555
x86_64_start_kernel+0x60/0x60 arch/x86/kernel/head64.c:536
secondary_startup_64_no_verify+0x179/0x17b
</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
Jul 12, 2025, 6:20:33 PM7/12/25
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following issue on:
HEAD commit: 59a2de10b81a Linux 6.6.97
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=15301d82580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ac0b29aca872266f
dashboard link: https://syzkaller.appspot.com/bug?extid=1d0ebb5530b0023d4b6b
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13301d82580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16778e8c580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7f81d6f618d8/disk-59a2de10.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e9aab5869c6f/vmlinux-59a2de10.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0ff4ec8c6205/bzImage-59a2de10.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1d0ebb...@syzkaller.appspotmail.com
watchdog: BUG: soft lockup - CPU#1 stuck for 143s! [swapper/1:0]
Modules linked in:
irq event stamp: 44549973
hardirqs last enabled at (44549972): [<ffffffff81705f36>] rcu_read_unlock_special+0x3c6/0x4c0 kernel/rcu/tree_plugin.h:678
hardirqs last disabled at (44549973): [<ffffffff8a6e7f3e>] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1088
softirqs last enabled at (44549940): [<ffffffff81518d67>] __do_softirq kernel/softirq.c:612 [inline]
softirqs last enabled at (44549940): [<ffffffff81518d67>] invoke_softirq kernel/softirq.c:452 [inline]
softirqs last enabled at (44549940): [<ffffffff81518d67>] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
softirqs last disabled at (44549943): [<ffffffff81518d67>] __do_softirq kernel/softirq.c:612 [inline]
softirqs last disabled at (44549943): [<ffffffff81518d67>] invoke_softirq kernel/softirq.c:452 [inline]
softirqs last disabled at (44549943): [<ffffffff81518d67>] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.6.97-syzkaller #0
RIP: 0010:write_comp_data kernel/kcov.c:245 [inline]
RIP: 0010:__sanitizer_cov_trace_switch+0x9f/0x120 kernel/kcov.c:350
Code: 4c 8b 05 54 1e 7e 7e 45 31 c9 eb 08 49 ff c1 4c 39 c8 74 77 4e 8b 54 ce 10 65 44 8b 1d 42 1e 7e 7e 41 81 e3 00 01 ff 00 74 13 <41> 81 fb 00 01 00 00 75 d9 41 83 b8 1c 16 00 00 00 74 cf 45 8b 98
RSP: 0018:ffffc900001f0450 EFLAGS: 00000206
RAX: 0000000000000020 RBX: 00000038e85685c8 RCX: 0000000000000005
RDX: ffffffff81889b7d RSI: ffffffff8cd799a0 RDI: 0000000000000004
RBP: 0000000000000004 R08: ffff88801ba6bc00 R09: 0000000000000008
R10: 0000000000000008 R11: 0000000000000100 R12: ffff88801c654114
R13: f800000000000000 R14: 0000000000000104 R15: 0000000000029b44
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
Call Trace:
<IRQ>
check_buffer+0x24d/0x950 kernel/trace/ring_buffer.c:3495
__rb_reserve_next+0x511/0xd50 kernel/trace/ring_buffer.c:3624
rb_reserve_next_event kernel/trace/ring_buffer.c:3759 [inline]
ring_buffer_lock_reserve+0xae1/0xed0 kernel/trace/ring_buffer.c:3818
__trace_buffer_lock_reserve kernel/trace/trace.c:992 [inline]
trace_event_buffer_lock_reserve+0x1d0/0x6e0 kernel/trace/trace.c:2902
trace_event_buffer_reserve+0x29b/0x3c0 kernel/trace/trace_events.c:661
do_trace_event_raw_event_bpf_trace_printk kernel/trace/bpf_trace.h:11 [inline]
trace_event_raw_event_bpf_trace_printk+0x101/0x210 kernel/trace/bpf_trace.h:11
trace_bpf_trace_printk+0x142/0x1a0 kernel/trace/bpf_trace.h:11
____bpf_trace_printk kernel/trace/bpf_trace.c:388 [inline]
bpf_trace_printk+0x11f/0x190 kernel/trace/bpf_trace.c:371
bpf_prog_9e1c00255e17e72e+0x38/0x3a
bpf_dispatcher_nop_func include/linux/bpf.h:1213 [inline]
__bpf_prog_run include/linux/filter.h:612 [inline]
bpf_prog_run include/linux/filter.h:619 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline]
bpf_trace_run1+0x1c9/0x3b0 kernel/trace/bpf_trace.c:2360
__bpf_trace_rcu_utilization+0xa2/0xe0 include/trace/events/rcu.h:27
__traceiter_rcu_utilization+0x70/0xa0 include/trace/events/rcu.h:27
trace_rcu_utilization+0x179/0x1a0 include/trace/events/rcu.h:27
rcu_core+0x1341/0x1720 kernel/rcu/tree.c:2475
handle_softirqs+0x280/0x820 kernel/softirq.c:578
__do_softirq kernel/softirq.c:612 [inline]
invoke_softirq kernel/softirq.c:452 [inline]
__irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
sysvec_irq_work+0xa1/0xc0 arch/x86/kernel/irq_work.c:17
</IRQ>
<TASK>
asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723
RSP: 0018:ffffc90000187de0 EFLAGS: 000002c2
RAX: ca20f1f92a99d300 RBX: ffffffff81618a7b RCX: ca20f1f92a99d300
RDX: 0000000000000001 RSI: ffffffff8aaab940 RDI: ffffffff8afc7880
RBP: ffffc90000187f20 R08: ffff8880b8f36d4b R09: 1ffff110171e6da9
R10: dffffc0000000000 R11: ffffed10171e6daa R12: ffffffff8e4a92e8
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff1100374d780
secondary_startup_64_no_verify+0x179/0x17b
</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.
HEAD commit: 59a2de10b81a Linux 6.6.97
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=15301d82580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ac0b29aca872266f
dashboard link: https://syzkaller.appspot.com/bug?extid=1d0ebb5530b0023d4b6b
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13301d82580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16778e8c580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7f81d6f618d8/disk-59a2de10.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e9aab5869c6f/vmlinux-59a2de10.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0ff4ec8c6205/bzImage-59a2de10.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1d0ebb...@syzkaller.appspotmail.com
Modules linked in:
irq event stamp: 44549973
hardirqs last enabled at (44549972): [<ffffffff81705f36>] rcu_read_unlock_special+0x3c6/0x4c0 kernel/rcu/tree_plugin.h:678
hardirqs last disabled at (44549973): [<ffffffff8a6e7f3e>] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1088
softirqs last enabled at (44549940): [<ffffffff81518d67>] __do_softirq kernel/softirq.c:612 [inline]
softirqs last enabled at (44549940): [<ffffffff81518d67>] invoke_softirq kernel/softirq.c:452 [inline]
softirqs last enabled at (44549940): [<ffffffff81518d67>] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
softirqs last disabled at (44549943): [<ffffffff81518d67>] __do_softirq kernel/softirq.c:612 [inline]
softirqs last disabled at (44549943): [<ffffffff81518d67>] invoke_softirq kernel/softirq.c:452 [inline]
softirqs last disabled at (44549943): [<ffffffff81518d67>] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.6.97-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:check_kcov_mode kernel/kcov.c:182 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:245 [inline]
RIP: 0010:__sanitizer_cov_trace_switch+0x9f/0x120 kernel/kcov.c:350
Code: 4c 8b 05 54 1e 7e 7e 45 31 c9 eb 08 49 ff c1 4c 39 c8 74 77 4e 8b 54 ce 10 65 44 8b 1d 42 1e 7e 7e 41 81 e3 00 01 ff 00 74 13 <41> 81 fb 00 01 00 00 75 d9 41 83 b8 1c 16 00 00 00 74 cf 45 8b 98
RSP: 0018:ffffc900001f0450 EFLAGS: 00000206
RAX: 0000000000000020 RBX: 00000038e85685c8 RCX: 0000000000000005
RDX: ffffffff81889b7d RSI: ffffffff8cd799a0 RDI: 0000000000000004
RBP: 0000000000000004 R08: ffff88801ba6bc00 R09: 0000000000000008
R10: 0000000000000008 R11: 0000000000000100 R12: ffff88801c654114
R13: f800000000000000 R14: 0000000000000104 R15: 0000000000029b44
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000018c0 CR3: 000000002385b000 CR4: 00000000003506e0
Call Trace:
<IRQ>
check_buffer+0x24d/0x950 kernel/trace/ring_buffer.c:3495
__rb_reserve_next+0x511/0xd50 kernel/trace/ring_buffer.c:3624
rb_reserve_next_event kernel/trace/ring_buffer.c:3759 [inline]
ring_buffer_lock_reserve+0xae1/0xed0 kernel/trace/ring_buffer.c:3818
__trace_buffer_lock_reserve kernel/trace/trace.c:992 [inline]
trace_event_buffer_lock_reserve+0x1d0/0x6e0 kernel/trace/trace.c:2902
trace_event_buffer_reserve+0x29b/0x3c0 kernel/trace/trace_events.c:661
do_trace_event_raw_event_bpf_trace_printk kernel/trace/bpf_trace.h:11 [inline]
trace_event_raw_event_bpf_trace_printk+0x101/0x210 kernel/trace/bpf_trace.h:11
trace_bpf_trace_printk+0x142/0x1a0 kernel/trace/bpf_trace.h:11
____bpf_trace_printk kernel/trace/bpf_trace.c:388 [inline]
bpf_trace_printk+0x11f/0x190 kernel/trace/bpf_trace.c:371
bpf_prog_9e1c00255e17e72e+0x38/0x3a
bpf_dispatcher_nop_func include/linux/bpf.h:1213 [inline]
__bpf_prog_run include/linux/filter.h:612 [inline]
bpf_prog_run include/linux/filter.h:619 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline]
bpf_trace_run1+0x1c9/0x3b0 kernel/trace/bpf_trace.c:2360
__bpf_trace_rcu_utilization+0xa2/0xe0 include/trace/events/rcu.h:27
__traceiter_rcu_utilization+0x70/0xa0 include/trace/events/rcu.h:27
trace_rcu_utilization+0x179/0x1a0 include/trace/events/rcu.h:27
rcu_core+0x1341/0x1720 kernel/rcu/tree.c:2475
handle_softirqs+0x280/0x820 kernel/softirq.c:578
__do_softirq kernel/softirq.c:612 [inline]
invoke_softirq kernel/softirq.c:452 [inline]
__irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
sysvec_irq_work+0xa1/0xc0 arch/x86/kernel/irq_work.c:17
</IRQ>
<TASK>
asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:148
Code: cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d 33 a6 39 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 66 0f 1f 00 55 41 57 41 56
RSP: 0018:ffffc90000187de0 EFLAGS: 000002c2
RAX: ca20f1f92a99d300 RBX: ffffffff81618a7b RCX: ca20f1f92a99d300
RDX: 0000000000000001 RSI: ffffffff8aaab940 RDI: ffffffff8afc7880
RBP: ffffc90000187f20 R08: ffff8880b8f36d4b R09: 1ffff110171e6da9
R10: dffffc0000000000 R11: ffffed10171e6daa R12: ffffffff8e4a92e8
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff1100374d780
arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:753
default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97
cpuidle_idle_call kernel/sched/idle.c:170 [inline]
do_idle+0x1eb/0x510 kernel/sched/idle.c:282
cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380
start_secondary+0xee/0xf0 arch/x86/kernel/smpboot.c:323
default_idle+0x13/0x20 arch/x86/kernel/process.c:753
default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97
cpuidle_idle_call kernel/sched/idle.c:170 [inline]
do_idle+0x1eb/0x510 kernel/sched/idle.c:282
cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380
secondary_startup_64_no_verify+0x179/0x17b
</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.
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