[v5.15] INFO: rcu detected stall in nsim_dev_trap_report_work (3)
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syzbot
Aug 20, 2025, 2:57:33 AM8/20/25
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: c79648372d02 Linux 5.15.189
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=122ee7a2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f3b1215b3cf4119f
dashboard link: https://syzkaller.appspot.com/bug?extid=adf3d9d216d554ccac29
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/fa511d2a8893/disk-c7964837.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f14b6c77bbb9/vmlinux-c7964837.xz
kernel image: https://storage.googleapis.com/syzbot-assets/388987ba15c6/bzImage-c7964837.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+adf3d9...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (0 ticks this GP) idle=39f/1/0x4000000000000000 softirq=15182/15182 fqs=10
(detected by 0, t=10502 jiffies, g=20265, q=282)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 1109 Comm: kworker/1:2 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: events nsim_dev_trap_report_work
RIP: 0010:lockdep_recursion_finish kernel/locking/lockdep.c:436 [inline]
RIP: 0010:lock_is_held_type+0x100/0x190 kernel/locking/lockdep.c:5667
Code: ff 74 16 89 e9 31 c0 41 f6 47 22 03 0f 95 c0 31 ed 39 c1 40 0f 94 c5 eb 05 bd 01 00 00 00 48 c7 c7 60 28 0b 8a e8 c0 0d 00 00 <b8> ff ff ff ff 65 0f c1 05 13 48 5a 76 83 f8 01 75 40 48 c7 04 24
RSP: 0018:ffffc90000dd0c38 EFLAGS: 00000082
RAX: 0000000000000001 RBX: ffff888020e55940 RCX: 11301bcc93a80800
RDX: 0000000000010000 RSI: ffffffff8a0b2860 RDI: ffffffff8a599340
RBP: 0000000000000001 R08: 0000000000000004 R09: 0000000000000003
R10: fffff520001ba180 R11: 1ffff920001ba180 R12: 0000000000000004
R13: 0000000000000046 R14: ffff88805e40a300 R15: ffff888020e564d0
FS: 0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c249de5 CR3: 000000007b7a6000 CR4: 00000000003526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
lock_is_held include/linux/lockdep.h:287 [inline]
advance_sched+0x141/0x940 net/sched/sch_taprio.c:721
__run_hrtimer kernel/time/hrtimer.c:1690 [inline]
__hrtimer_run_queues+0x53d/0xc40 kernel/time/hrtimer.c:1754
hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816
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:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:preempt_count_sub+0x2c/0x160 kernel/sched/core.c:5517
Code: 48 bb 00 00 00 00 00 fc ff df 48 c7 c0 60 df 0b 96 48 c1 e8 03 0f b6 04 18 84 c0 0f 85 bd 00 00 00 83 3d 16 6f ba 14 00 75 25 <65> 8b 05 75 ff b0 7e 89 c1 81 e1 ff ff ff 7f 39 cf 7f 25 81 ff ff
RSP: 0018:ffffc90004767650 EFLAGS: 00000246
RAX: 0000000000000004 RBX: dffffc0000000000 RCX: ffffffff960bdf03
RDX: ffffc90004767701 RSI: ffffc90004767778 RDI: 0000000000000001
RBP: ffffc900047677d0 R08: dffffc0000000000 R09: ffffc900047677d8
R10: fffff520008ecefd R11: 1ffff920008ecefb R12: ffffc90004760000
R13: dffffc0000000000 R14: ffffc90004767798 R15: ffffc90004767788
unwind_next_frame+0x1296/0x1d90 arch/x86/kernel/unwind_orc.c:616
__unwind_start+0x5bb/0x740 arch/x86/kernel/unwind_orc.c:704
unwind_start arch/x86/include/asm/unwind.h:60 [inline]
arch_stack_walk+0xda/0x140 arch/x86/kernel/stacktrace.c:24
stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
____kasan_kmalloc mm/kasan/common.c:513 [inline]
__kasan_kmalloc+0xb5/0xf0 mm/kasan/common.c:522
kmalloc_reserve net/core/skbuff.c:356 [inline]
__alloc_skb+0x22c/0x750 net/core/skbuff.c:427
alloc_skb include/linux/skbuff.h:1162 [inline]
nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:664 [inline]
nsim_dev_trap_report drivers/net/netdevsim/dev.c:721 [inline]
nsim_dev_trap_report_work+0x2a1/0xb40 drivers/net/netdevsim/dev.c:762
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 10450 jiffies! g20265 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:28128 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
schedule+0x11b/0x1e0 kernel/sched/core.c:6459
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 0
CPU: 0 PID: 6353 Comm: syz.9.455 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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:1690 [inline]
__hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1754
hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816
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:csd_lock_wait kernel/smp.c:440 [inline]
RIP: 0010:smp_call_function_single+0x212/0x490 kernel/smp.c:758
Code: 48 44 89 f6 83 e6 01 31 ff e8 0a 5c 0b 00 41 83 e6 01 49 bc 00 00 00 00 00 fc ff df 75 0a e8 95 58 0b 00 e9 a3 00 00 00 f3 90 <f7> 44 24 48 01 00 00 00 0f 84 8e 00 00 00 e8 7b 58 0b 00 eb e9 e8
RSP: 0018:ffffc900015bf900 EFLAGS: 00000246
RAX: ffffffff816c6ba5 RBX: 0000000000000000 RCX: 0000000000080000
RDX: ffffc9000fe21000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc900015bf9f0 R08: dffffc0000000000 R09: ffffed1017227679
R10: ffffed1017227679 R11: 1ffff11017227678 R12: dffffc0000000000
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff920002b7f24
loaded_vmcs_clear arch/x86/kvm/vmx/vmx.c:723 [inline]
vmx_vcpu_load_vmcs+0x12a/0x780 arch/x86/kvm/vmx/vmx.c:1315
vmx_vcpu_load+0x1a/0x80 arch/x86/kvm/vmx/vmx.c:1380
kvm_arch_vcpu_load+0x190/0x770 arch/x86/kvm/x86.c:4385
vcpu_load+0x4e/0x80 virt/kvm/kvm_main.c:209
kvm_arch_vcpu_ioctl_run+0x53/0x1f40 arch/x86/kvm/x86.c:10337
kvm_vcpu_ioctl+0x887/0xb80 virt/kvm/kvm_main.c:3894
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
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: 0033:0x7f5a9b788be9
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:00007f5a999ae038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f5a9b9b0180 RCX: 00007f5a9b788be9
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005
RBP: 00007f5a9b80be19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5a9b9b0218 R14: 00007f5a9b9b0180 R15: 00007fff8531b8b8
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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If you want to undo deduplication, reply with:
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syzbot found the following issue on:
HEAD commit: c79648372d02 Linux 5.15.189
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=122ee7a2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f3b1215b3cf4119f
dashboard link: https://syzkaller.appspot.com/bug?extid=adf3d9d216d554ccac29
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/fa511d2a8893/disk-c7964837.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f14b6c77bbb9/vmlinux-c7964837.xz
kernel image: https://storage.googleapis.com/syzbot-assets/388987ba15c6/bzImage-c7964837.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+adf3d9...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (0 ticks this GP) idle=39f/1/0x4000000000000000 softirq=15182/15182 fqs=10
(detected by 0, t=10502 jiffies, g=20265, q=282)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 1109 Comm: kworker/1:2 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: events nsim_dev_trap_report_work
RIP: 0010:lockdep_recursion_finish kernel/locking/lockdep.c:436 [inline]
RIP: 0010:lock_is_held_type+0x100/0x190 kernel/locking/lockdep.c:5667
Code: ff 74 16 89 e9 31 c0 41 f6 47 22 03 0f 95 c0 31 ed 39 c1 40 0f 94 c5 eb 05 bd 01 00 00 00 48 c7 c7 60 28 0b 8a e8 c0 0d 00 00 <b8> ff ff ff ff 65 0f c1 05 13 48 5a 76 83 f8 01 75 40 48 c7 04 24
RSP: 0018:ffffc90000dd0c38 EFLAGS: 00000082
RAX: 0000000000000001 RBX: ffff888020e55940 RCX: 11301bcc93a80800
RDX: 0000000000010000 RSI: ffffffff8a0b2860 RDI: ffffffff8a599340
RBP: 0000000000000001 R08: 0000000000000004 R09: 0000000000000003
R10: fffff520001ba180 R11: 1ffff920001ba180 R12: 0000000000000004
R13: 0000000000000046 R14: ffff88805e40a300 R15: ffff888020e564d0
FS: 0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c249de5 CR3: 000000007b7a6000 CR4: 00000000003526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
lock_is_held include/linux/lockdep.h:287 [inline]
advance_sched+0x141/0x940 net/sched/sch_taprio.c:721
__run_hrtimer kernel/time/hrtimer.c:1690 [inline]
__hrtimer_run_queues+0x53d/0xc40 kernel/time/hrtimer.c:1754
hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816
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:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:preempt_count_sub+0x2c/0x160 kernel/sched/core.c:5517
Code: 48 bb 00 00 00 00 00 fc ff df 48 c7 c0 60 df 0b 96 48 c1 e8 03 0f b6 04 18 84 c0 0f 85 bd 00 00 00 83 3d 16 6f ba 14 00 75 25 <65> 8b 05 75 ff b0 7e 89 c1 81 e1 ff ff ff 7f 39 cf 7f 25 81 ff ff
RSP: 0018:ffffc90004767650 EFLAGS: 00000246
RAX: 0000000000000004 RBX: dffffc0000000000 RCX: ffffffff960bdf03
RDX: ffffc90004767701 RSI: ffffc90004767778 RDI: 0000000000000001
RBP: ffffc900047677d0 R08: dffffc0000000000 R09: ffffc900047677d8
R10: fffff520008ecefd R11: 1ffff920008ecefb R12: ffffc90004760000
R13: dffffc0000000000 R14: ffffc90004767798 R15: ffffc90004767788
unwind_next_frame+0x1296/0x1d90 arch/x86/kernel/unwind_orc.c:616
__unwind_start+0x5bb/0x740 arch/x86/kernel/unwind_orc.c:704
unwind_start arch/x86/include/asm/unwind.h:60 [inline]
arch_stack_walk+0xda/0x140 arch/x86/kernel/stacktrace.c:24
stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
____kasan_kmalloc mm/kasan/common.c:513 [inline]
__kasan_kmalloc+0xb5/0xf0 mm/kasan/common.c:522
kmalloc_reserve net/core/skbuff.c:356 [inline]
__alloc_skb+0x22c/0x750 net/core/skbuff.c:427
alloc_skb include/linux/skbuff.h:1162 [inline]
nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:664 [inline]
nsim_dev_trap_report drivers/net/netdevsim/dev.c:721 [inline]
nsim_dev_trap_report_work+0x2a1/0xb40 drivers/net/netdevsim/dev.c:762
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 10450 jiffies! g20265 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:28128 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
schedule+0x11b/0x1e0 kernel/sched/core.c:6459
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 0
CPU: 0 PID: 6353 Comm: syz.9.455 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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:1690 [inline]
__hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1754
hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816
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:csd_lock_wait kernel/smp.c:440 [inline]
RIP: 0010:smp_call_function_single+0x212/0x490 kernel/smp.c:758
Code: 48 44 89 f6 83 e6 01 31 ff e8 0a 5c 0b 00 41 83 e6 01 49 bc 00 00 00 00 00 fc ff df 75 0a e8 95 58 0b 00 e9 a3 00 00 00 f3 90 <f7> 44 24 48 01 00 00 00 0f 84 8e 00 00 00 e8 7b 58 0b 00 eb e9 e8
RSP: 0018:ffffc900015bf900 EFLAGS: 00000246
RAX: ffffffff816c6ba5 RBX: 0000000000000000 RCX: 0000000000080000
RDX: ffffc9000fe21000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc900015bf9f0 R08: dffffc0000000000 R09: ffffed1017227679
R10: ffffed1017227679 R11: 1ffff11017227678 R12: dffffc0000000000
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff920002b7f24
loaded_vmcs_clear arch/x86/kvm/vmx/vmx.c:723 [inline]
vmx_vcpu_load_vmcs+0x12a/0x780 arch/x86/kvm/vmx/vmx.c:1315
vmx_vcpu_load+0x1a/0x80 arch/x86/kvm/vmx/vmx.c:1380
kvm_arch_vcpu_load+0x190/0x770 arch/x86/kvm/x86.c:4385
vcpu_load+0x4e/0x80 virt/kvm/kvm_main.c:209
kvm_arch_vcpu_ioctl_run+0x53/0x1f40 arch/x86/kvm/x86.c:10337
kvm_vcpu_ioctl+0x887/0xb80 virt/kvm/kvm_main.c:3894
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
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: 0033:0x7f5a9b788be9
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:00007f5a999ae038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f5a9b9b0180 RCX: 00007f5a9b788be9
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005
RBP: 00007f5a9b80be19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5a9b9b0218 R14: 00007f5a9b9b0180 R15: 00007fff8531b8b8
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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syzbot will keep track of this issue. See:
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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:
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(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
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If you want to undo deduplication, reply with:
#syz undup
syzbot
Nov 22, 2025, 4:28:25 AM11/22/25
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following issue on:
HEAD commit: cc5ec8769306 Linux 5.15.196
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=16c8b658580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e1bb6d24ef2164eb
dashboard link: https://syzkaller.appspot.com/bug?extid=adf3d9d216d554ccac29
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1563d97c580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10f698b4580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ed7568bc5bb4/disk-cc5ec876.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e343e0aaac77/vmlinux-cc5ec876.xz
kernel image: https://storage.googleapis.com/syzbot-assets/089870f2a980/bzImage-cc5ec876.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+adf3d9...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 ticks this GP) idle=e2f/1/0x4000000000000002 softirq=21889/21889 fqs=0
(detected by 1, t=10502 jiffies, g=36977, q=195)
Sending NMI from CPU 1 to CPUs 0:
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: events nsim_dev_trap_report_work
RIP: 0010:check_kcov_mode kernel/kcov.c:172 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x13/0x60 kernel/kcov.c:206
Code: 48 8b 3d 50 d3 f1 0b 48 89 de 5b e9 57 9e 43 00 00 00 cc cc 00 00 cc 48 8b 04 24 65 48 8b 0d a4 a3 8a 7e 65 8b 15 a5 a3 8a 7e <81> e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 34 16 00 00
RSP: 0018:ffffc90000006fa0 EFLAGS: 00000046
RAX: ffffffff810eaa56 RBX: ffff8880b90351c8 RCX: ffff8880296bbb80
RDX: 0000000000000104 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: dffffc0000000000 R09: ffffc90000007120
R10: fffff52000000e2b R11: 1ffff92000000e24 R12: dffffc0000000000
R13: ffffc90000007186 R14: ffffffff8bf23a40 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
perf_misc_flags+0x8f/0x1b0 arch/x86/events/core.c:2964
perf_prepare_sample+0x132/0x1cb0 kernel/events/core.c:7622
__perf_event_output kernel/events/core.c:7802 [inline]
perf_event_output_forward+0x146/0x280 kernel/events/core.c:7822
__perf_event_overflow+0x364/0x530 kernel/events/core.c:9515
perf_swevent_overflow kernel/events/core.c:9591 [inline]
perf_swevent_event+0x4ad/0x530 kernel/events/core.c:9629
perf_tp_event+0x32c/0xb50 kernel/events/core.c:10047
perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021
perf_trace_preemptirq_template+0x2be/0x380 include/trace/events/preemptirq.h:14
trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40
trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44
asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x84/0x480 kernel/rcu/tree_plugin.h:674
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 ed 11 9e 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc90000007780 EFLAGS: 00000206
RAX: 4b3c6d95c972ca00 RBX: 1ffff92000000ef4 RCX: 4b3c6d95c972ca00
RDX: dffffc0000000000 RSI: ffffffff8a0b1c60 RDI: ffffffff8a59e580
RBP: ffffc90000007860 R08: dffffc0000000000 R09: fffffbfff1ff7c32
R10: fffffbfff1ff7c32 R11: 1ffffffff1ff7c31 R12: ffffffff8c120c00
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
__rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
rcu_read_unlock include/linux/rcupdate.h:772 [inline]
__ip_queue_xmit+0x1244/0x1c00 net/ipv4/ip_output.c:533
__tcp_transmit_skb+0x1ced/0x31c0 net/ipv4/tcp_output.c:1404
tcp_delack_timer_handler+0x32e/0x730 net/ipv4/tcp_timer.c:314
tcp_delack_timer+0x188/0x2e0 net/ipv4/tcp_timer.c:341
call_timer_fn+0x16c/0x530 kernel/time/timer.c:1451
expire_timers kernel/time/timer.c:1496 [inline]
__run_timers+0x525/0x7c0 kernel/time/timer.c:1767
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780
handle_softirqs+0x328/0x820 kernel/softirq.c:576
__do_softirq kernel/softirq.c:610 [inline]
invoke_softirq kernel/softirq.c:450 [inline]
__irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659
irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
RIP: 0010:_raw_spin_unlock_irqrestore+0xa5/0x100 kernel/locking/spinlock.c:194
Code: 74 05 e8 de 0d cb f7 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> f6 95 9e f7 65 8b 05 87 93 4f 76 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc900031ef8c0 EFLAGS: 00000206
RAX: 4b3c6d95c972ca00 RBX: 0000000000000a06 RCX: 4b3c6d95c972ca00
RDX: dffffc0000000000 RSI: ffffffff8a0b1c60 RDI: 0000000000000001
RBP: ffffc900031ef948 R08: dffffc0000000000 R09: fffffbfff1ff7c3b
R10: fffffbfff1ff7c3b R11: 1ffffffff1ff7c3a R12: dffffc0000000000
R13: ffff888075c32000 R14: ffffffff96301880 R15: 1ffff9200063df18
__debug_check_no_obj_freed lib/debugobjects.c:982 [inline]
debug_check_no_obj_freed+0x515/0x530 lib/debugobjects.c:1003
slab_free_hook mm/slub.c:1685 [inline]
slab_free_freelist_hook+0x8b/0x170 mm/slub.c:1736
slab_free mm/slub.c:3504 [inline]
kfree+0xef/0x2a0 mm/slub.c:4564
skb_free_head net/core/skbuff.c:655 [inline]
skb_release_data+0x6fe/0x850 net/core/skbuff.c:677
skb_release_all net/core/skbuff.c:742 [inline]
__kfree_skb net/core/skbuff.c:756 [inline]
consume_skb+0xa2/0x100 net/core/skbuff.c:914
nsim_dev_trap_report drivers/net/netdevsim/dev.c:737 [inline]
nsim_dev_trap_report_work+0x7cb/0xb40 drivers/net/netdevsim/dev.c:762
rcu: Possible timer handling issue on cpu=0 timer-softirq=19856
rcu: rcu_preempt kthread starved for 10502 jiffies! g36977 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
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
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: events nsim_dev_trap_report_work
RIP: 0010:rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:331 [inline]
RIP: 0010:rcu_is_watching+0x36/0xa0 kernel/rcu/tree.c:1123
Code: e8 9f cc 45 08 89 c3 83 f8 08 73 5c 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd 20 c8 bc 8b 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 <74> 08 4c 89 f7 e8 c0 82 58 00 48 c7 c3 08 b3 03 00 49 03 1e 48 89
RSP: 0018:ffffc900000070c0 EFLAGS: 00000046
RAX: 1ffffffff1779904 RBX: 0000000000000000 RCX: 4b3c6d95c972ca00
RDX: 0000000000000100 RSI: ffffffff8a59e560 RDI: ffffffff8a59e520
RBP: ffffc900000071f8 R08: dffffc0000000000 R09: fffffbfff1ad33a6
R10: fffffbfff1ad33a6 R11: 1ffffffff1ad33a5 R12: 00000000ffffffe4
R13: 1ffff92000000e20 R14: ffffffff8bbcc820 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
__perf_event_output kernel/events/core.c:7813 [inline]
perf_event_output_forward+0x1b0/0x280 kernel/events/core.c:7822
__perf_event_overflow+0x364/0x530 kernel/events/core.c:9515
perf_swevent_overflow kernel/events/core.c:9591 [inline]
perf_swevent_event+0x4ad/0x530 kernel/events/core.c:9629
perf_tp_event+0x32c/0xb50 kernel/events/core.c:10047
perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021
perf_trace_preemptirq_template+0x2be/0x380 include/trace/events/preemptirq.h:14
trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40
trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44
asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x84/0x480 kernel/rcu/tree_plugin.h:674
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 ed 11 9e 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc90000007780 EFLAGS: 00000206
RAX: 4b3c6d95c972ca00 RBX: 1ffff92000000ef4 RCX: 4b3c6d95c972ca00
RDX: dffffc0000000000 RSI: ffffffff8a0b1c60 RDI: ffffffff8a59e580
RBP: ffffc90000007860 R08: dffffc0000000000 R09: fffffbfff1ff7c32
R10: fffffbfff1ff7c32 R11: 1ffffffff1ff7c31 R12: ffffffff8c120c00
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
__rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
rcu_read_unlock include/linux/rcupdate.h:772 [inline]
__ip_queue_xmit+0x1244/0x1c00 net/ipv4/ip_output.c:533
__tcp_transmit_skb+0x1ced/0x31c0 net/ipv4/tcp_output.c:1404
tcp_delack_timer_handler+0x32e/0x730 net/ipv4/tcp_timer.c:314
tcp_delack_timer+0x188/0x2e0 net/ipv4/tcp_timer.c:341
call_timer_fn+0x16c/0x530 kernel/time/timer.c:1451
expire_timers kernel/time/timer.c:1496 [inline]
__run_timers+0x525/0x7c0 kernel/time/timer.c:1767
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780
handle_softirqs+0x328/0x820 kernel/softirq.c:576
__do_softirq kernel/softirq.c:610 [inline]
invoke_softirq kernel/softirq.c:450 [inline]
__irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659
irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
RIP: 0010:_raw_spin_unlock_irqrestore+0xa5/0x100 kernel/locking/spinlock.c:194
Code: 74 05 e8 de 0d cb f7 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> f6 95 9e f7 65 8b 05 87 93 4f 76 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc900031ef8c0 EFLAGS: 00000206
RAX: 4b3c6d95c972ca00 RBX: 0000000000000a06 RCX: 4b3c6d95c972ca00
RDX: dffffc0000000000 RSI: ffffffff8a0b1c60 RDI: 0000000000000001
RBP: ffffc900031ef948 R08: dffffc0000000000 R09: fffffbfff1ff7c3b
R10: fffffbfff1ff7c3b R11: 1ffffffff1ff7c3a R12: dffffc0000000000
R13: ffff888075c32000 R14: ffffffff96301880 R15: 1ffff9200063df18
__debug_check_no_obj_freed lib/debugobjects.c:982 [inline]
debug_check_no_obj_freed+0x515/0x530 lib/debugobjects.c:1003
slab_free_hook mm/slub.c:1685 [inline]
slab_free_freelist_hook+0x8b/0x170 mm/slub.c:1736
slab_free mm/slub.c:3504 [inline]
kfree+0xef/0x2a0 mm/slub.c:4564
skb_free_head net/core/skbuff.c:655 [inline]
skb_release_data+0x6fe/0x850 net/core/skbuff.c:677
skb_release_all net/core/skbuff.c:742 [inline]
__kfree_skb net/core/skbuff.c:756 [inline]
consume_skb+0xa2/0x100 net/core/skbuff.c:914
nsim_dev_trap_report drivers/net/netdevsim/dev.c:737 [inline]
nsim_dev_trap_report_work+0x7cb/0xb40 drivers/net/netdevsim/dev.c:762
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: cc5ec8769306 Linux 5.15.196
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=16c8b658580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e1bb6d24ef2164eb
dashboard link: https://syzkaller.appspot.com/bug?extid=adf3d9d216d554ccac29
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1563d97c580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10f698b4580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ed7568bc5bb4/disk-cc5ec876.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e343e0aaac77/vmlinux-cc5ec876.xz
kernel image: https://storage.googleapis.com/syzbot-assets/089870f2a980/bzImage-cc5ec876.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+adf3d9...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
(detected by 1, t=10502 jiffies, g=36977, q=195)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4309 Comm: kworker/0:17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: events nsim_dev_trap_report_work
RIP: 0010:check_kcov_mode kernel/kcov.c:172 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x13/0x60 kernel/kcov.c:206
Code: 48 8b 3d 50 d3 f1 0b 48 89 de 5b e9 57 9e 43 00 00 00 cc cc 00 00 cc 48 8b 04 24 65 48 8b 0d a4 a3 8a 7e 65 8b 15 a5 a3 8a 7e <81> e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 34 16 00 00
RSP: 0018:ffffc90000006fa0 EFLAGS: 00000046
RAX: ffffffff810eaa56 RBX: ffff8880b90351c8 RCX: ffff8880296bbb80
RDX: 0000000000000104 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: dffffc0000000000 R09: ffffc90000007120
R10: fffff52000000e2b R11: 1ffff92000000e24 R12: dffffc0000000000
R13: ffffc90000007186 R14: ffffffff8bf23a40 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33463fff CR3: 0000000029b99000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
kvm_is_in_guest+0x6/0x30 arch/x86/kvm/x86.c:8595
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
perf_misc_flags+0x8f/0x1b0 arch/x86/events/core.c:2964
perf_prepare_sample+0x132/0x1cb0 kernel/events/core.c:7622
__perf_event_output kernel/events/core.c:7802 [inline]
perf_event_output_forward+0x146/0x280 kernel/events/core.c:7822
__perf_event_overflow+0x364/0x530 kernel/events/core.c:9515
perf_swevent_overflow kernel/events/core.c:9591 [inline]
perf_swevent_event+0x4ad/0x530 kernel/events/core.c:9629
perf_tp_event+0x32c/0xb50 kernel/events/core.c:10047
perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021
perf_trace_preemptirq_template+0x2be/0x380 include/trace/events/preemptirq.h:14
trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40
trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44
asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x84/0x480 kernel/rcu/tree_plugin.h:674
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 ed 11 9e 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc90000007780 EFLAGS: 00000206
RAX: 4b3c6d95c972ca00 RBX: 1ffff92000000ef4 RCX: 4b3c6d95c972ca00
RDX: dffffc0000000000 RSI: ffffffff8a0b1c60 RDI: ffffffff8a59e580
RBP: ffffc90000007860 R08: dffffc0000000000 R09: fffffbfff1ff7c32
R10: fffffbfff1ff7c32 R11: 1ffffffff1ff7c31 R12: ffffffff8c120c00
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
__rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
rcu_read_unlock include/linux/rcupdate.h:772 [inline]
__ip_queue_xmit+0x1244/0x1c00 net/ipv4/ip_output.c:533
__tcp_transmit_skb+0x1ced/0x31c0 net/ipv4/tcp_output.c:1404
tcp_delack_timer_handler+0x32e/0x730 net/ipv4/tcp_timer.c:314
tcp_delack_timer+0x188/0x2e0 net/ipv4/tcp_timer.c:341
call_timer_fn+0x16c/0x530 kernel/time/timer.c:1451
expire_timers kernel/time/timer.c:1496 [inline]
__run_timers+0x525/0x7c0 kernel/time/timer.c:1767
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780
handle_softirqs+0x328/0x820 kernel/softirq.c:576
__do_softirq kernel/softirq.c:610 [inline]
invoke_softirq kernel/softirq.c:450 [inline]
__irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659
irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 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:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:_raw_spin_unlock_irqrestore+0xa5/0x100 kernel/locking/spinlock.c:194
Code: 74 05 e8 de 0d cb f7 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> f6 95 9e f7 65 8b 05 87 93 4f 76 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc900031ef8c0 EFLAGS: 00000206
RAX: 4b3c6d95c972ca00 RBX: 0000000000000a06 RCX: 4b3c6d95c972ca00
RDX: dffffc0000000000 RSI: ffffffff8a0b1c60 RDI: 0000000000000001
RBP: ffffc900031ef948 R08: dffffc0000000000 R09: fffffbfff1ff7c3b
R10: fffffbfff1ff7c3b R11: 1ffffffff1ff7c3a R12: dffffc0000000000
R13: ffff888075c32000 R14: ffffffff96301880 R15: 1ffff9200063df18
__debug_check_no_obj_freed lib/debugobjects.c:982 [inline]
debug_check_no_obj_freed+0x515/0x530 lib/debugobjects.c:1003
slab_free_hook mm/slub.c:1685 [inline]
slab_free_freelist_hook+0x8b/0x170 mm/slub.c:1736
slab_free mm/slub.c:3504 [inline]
kfree+0xef/0x2a0 mm/slub.c:4564
skb_free_head net/core/skbuff.c:655 [inline]
skb_release_data+0x6fe/0x850 net/core/skbuff.c:677
skb_release_all net/core/skbuff.c:742 [inline]
__kfree_skb net/core/skbuff.c:756 [inline]
consume_skb+0xa2/0x100 net/core/skbuff.c:914
nsim_dev_trap_report drivers/net/netdevsim/dev.c:737 [inline]
nsim_dev_trap_report_work+0x7cb/0xb40 drivers/net/netdevsim/dev.c:762
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 timer wakeup didn't happen for 10501 jiffies! g36977 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
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: Possible timer handling issue on cpu=0 timer-softirq=19856
rcu: rcu_preempt kthread starved for 10502 jiffies! g36977 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:27328 pid: 15 ppid: 2 flags:0x00004000
rcu: RCU grace-period kthread stack dump:
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:
Sending NMI from CPU 1 to CPUs 0:
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 0
CPU: 0 PID: 4309 Comm: kworker/0:17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: events nsim_dev_trap_report_work
RIP: 0010:rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:331 [inline]
RIP: 0010:rcu_is_watching+0x36/0xa0 kernel/rcu/tree.c:1123
Code: e8 9f cc 45 08 89 c3 83 f8 08 73 5c 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd 20 c8 bc 8b 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 <74> 08 4c 89 f7 e8 c0 82 58 00 48 c7 c3 08 b3 03 00 49 03 1e 48 89
RSP: 0018:ffffc900000070c0 EFLAGS: 00000046
RAX: 1ffffffff1779904 RBX: 0000000000000000 RCX: 4b3c6d95c972ca00
RDX: 0000000000000100 RSI: ffffffff8a59e560 RDI: ffffffff8a59e520
RBP: ffffc900000071f8 R08: dffffc0000000000 R09: fffffbfff1ad33a6
R10: fffffbfff1ad33a6 R11: 1ffffffff1ad33a5 R12: 00000000ffffffe4
R13: 1ffff92000000e20 R14: ffffffff8bbcc820 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33463fff CR3: 0000000029b99000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
rcu_read_unlock include/linux/rcupdate.h:769 [inline]
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
__perf_event_output kernel/events/core.c:7813 [inline]
perf_event_output_forward+0x1b0/0x280 kernel/events/core.c:7822
__perf_event_overflow+0x364/0x530 kernel/events/core.c:9515
perf_swevent_overflow kernel/events/core.c:9591 [inline]
perf_swevent_event+0x4ad/0x530 kernel/events/core.c:9629
perf_tp_event+0x32c/0xb50 kernel/events/core.c:10047
perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021
perf_trace_preemptirq_template+0x2be/0x380 include/trace/events/preemptirq.h:14
trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40
trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44
asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x84/0x480 kernel/rcu/tree_plugin.h:674
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 ed 11 9e 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc90000007780 EFLAGS: 00000206
RAX: 4b3c6d95c972ca00 RBX: 1ffff92000000ef4 RCX: 4b3c6d95c972ca00
RDX: dffffc0000000000 RSI: ffffffff8a0b1c60 RDI: ffffffff8a59e580
RBP: ffffc90000007860 R08: dffffc0000000000 R09: fffffbfff1ff7c32
R10: fffffbfff1ff7c32 R11: 1ffffffff1ff7c31 R12: ffffffff8c120c00
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
__rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
rcu_read_unlock include/linux/rcupdate.h:772 [inline]
__ip_queue_xmit+0x1244/0x1c00 net/ipv4/ip_output.c:533
__tcp_transmit_skb+0x1ced/0x31c0 net/ipv4/tcp_output.c:1404
tcp_delack_timer_handler+0x32e/0x730 net/ipv4/tcp_timer.c:314
tcp_delack_timer+0x188/0x2e0 net/ipv4/tcp_timer.c:341
call_timer_fn+0x16c/0x530 kernel/time/timer.c:1451
expire_timers kernel/time/timer.c:1496 [inline]
__run_timers+0x525/0x7c0 kernel/time/timer.c:1767
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780
handle_softirqs+0x328/0x820 kernel/softirq.c:576
__do_softirq kernel/softirq.c:610 [inline]
invoke_softirq kernel/softirq.c:450 [inline]
__irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659
irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 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:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:_raw_spin_unlock_irqrestore+0xa5/0x100 kernel/locking/spinlock.c:194
Code: 74 05 e8 de 0d cb f7 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> f6 95 9e f7 65 8b 05 87 93 4f 76 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc900031ef8c0 EFLAGS: 00000206
RAX: 4b3c6d95c972ca00 RBX: 0000000000000a06 RCX: 4b3c6d95c972ca00
RDX: dffffc0000000000 RSI: ffffffff8a0b1c60 RDI: 0000000000000001
RBP: ffffc900031ef948 R08: dffffc0000000000 R09: fffffbfff1ff7c3b
R10: fffffbfff1ff7c3b R11: 1ffffffff1ff7c3a R12: dffffc0000000000
R13: ffff888075c32000 R14: ffffffff96301880 R15: 1ffff9200063df18
__debug_check_no_obj_freed lib/debugobjects.c:982 [inline]
debug_check_no_obj_freed+0x515/0x530 lib/debugobjects.c:1003
slab_free_hook mm/slub.c:1685 [inline]
slab_free_freelist_hook+0x8b/0x170 mm/slub.c:1736
slab_free mm/slub.c:3504 [inline]
kfree+0xef/0x2a0 mm/slub.c:4564
skb_free_head net/core/skbuff.c:655 [inline]
skb_release_data+0x6fe/0x850 net/core/skbuff.c:677
skb_release_all net/core/skbuff.c:742 [inline]
__kfree_skb net/core/skbuff.c:756 [inline]
consume_skb+0xa2/0x100 net/core/skbuff.c:914
nsim_dev_trap_report drivers/net/netdevsim/dev.c:737 [inline]
nsim_dev_trap_report_work+0x7cb/0xb40 drivers/net/netdevsim/dev.c:762
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>
---
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>
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#syz test: git://repo/address.git branch-or-commit-hash
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