BUG: soft lockup in trace_call_bpf

Status: moderation: reported on 2026/10/15 15:13
Subsystems: perf
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+ec473beef92531127ba1@syzkaller.appspotmail.com
First crash: 4d11h, last: 4d11h
▶ ▼ ✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
8bc27af7 repro-c 💥 BUG: soft lockup in trace_call_bpf 2026/10/14 02:11 2026/10/14 02:11 2026/10/14 04:54 7321cd29
a63a030b assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ BUG: soft lockup in trace_call_bpf 2026/10/13 07:13 2026/10/13 07:13 2026/10/13 08:48 745a967f
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: rcu detected stall in trace_call_bpf 1 1 123d 123d 0/3 auto-obsoleted due to no activity on 2026/09/22 23:57

Sample crash report:
watchdog: BUG: soft lockup - CPU#0 stuck for 113s! [syz.1.451:7926]
Modules linked in:
irq event stamp: 321319
hardirqs last  enabled at (321318): [<ffffffff8beaefa0>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:210 [inline]
hardirqs last  enabled at (321318): [<ffffffff8beaefa0>] _raw_spin_unlock_irqrestore+0x30/0x80 kernel/locking/spinlock.c:221
hardirqs last disabled at (321319): [<ffffffff8be82c2e>] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1062
softirqs last  enabled at (316428): [<ffffffff816d6120>] local_bh_disable include/linux/bottom_half.h:20 [inline]
softirqs last  enabled at (316428): [<ffffffff816d6120>] fpregs_lock arch/x86/include/asm/fpu/api.h:69 [inline]
softirqs last  enabled at (316428): [<ffffffff816d6120>] fpu_clone+0x340/0xaf0 arch/x86/kernel/fpu/core.c:710
softirqs last disabled at (316725): [<ffffffff81891e7b>] __do_softirq kernel/softirq.c:679 [inline]
softirqs last disabled at (316725): [<ffffffff81891e7b>] invoke_softirq kernel/softirq.c:519 [inline]
softirqs last disabled at (316725): [<ffffffff81891e7b>] __irq_exit_rcu+0xcb/0x220 kernel/softirq.c:758
CPU: 0 UID: 0 PID: 7926 Comm: syz.1.451 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:kasan_byte_accessible+0x18/0x30 mm/kasan/generic.c:212
Code: 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 48 c1 ef 03 48 b8 00 00 00 00 00 fc ff df 0f b6 04 07 3c 08 <0f> 92 c0 c3 cc cc cc cc cc 66 66 66 66 66 66 2e 0f 1f 84 00 00 00
RSP: 0000:ffffc90000007908 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffffffff81d45035 RCX: 0000000000000102
RDX: 0000000000000004 RSI: ffffffff81d45035 RDI: 1ffffffff1fab914
RBP: 0000000000000000 R08: 0000000000000002 R09: 0000000000000000
R10: 723e2d7665646e26 R11: 2972656d69745f73 R12: ffffffff8fd5c8a0
R13: 0000000000000002 R14: ffffffff8fd5c8a0 R15: 0000000000000000
FS:  00007fdd5f7cd6c0(0000) GS:ffff888123ac0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555563f147e0 CR3: 000000007a21a000 CR4: 00000000003526f0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000008d24
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 __kasan_check_byte+0x12/0x40 mm/kasan/common.c:584
 kasan_check_byte include/linux/kasan.h:402 [inline]
 lock_acquire+0x7d/0x350 kernel/locking/lockdep.c:5916
 rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 trace_call_bpf+0xd5/0xb80 kernel/trace/bpf_trace.c:-1
 perf_trace_run_bpf_submit+0x78/0x170 kernel/events/core.c:11440
 do_perf_trace_lock include/trace/events/lock.h:49 [inline]
 perf_trace_lock+0x32e/0x410 include/trace/events/lock.h:49
 __do_trace_lock_release include/trace/events/lock.h:68 [inline]
 trace_lock_release include/trace/events/lock.h:68 [inline]
 lock_release+0x396/0x3c0 kernel/locking/lockdep.c:5954
 call_timer_fn+0x227/0x5f0 kernel/time/timer.c:1751
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2374 [inline]
 __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386
 run_timer_base kernel/time/timer.c:2395 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
 handle_softirqs+0x226/0x860 kernel/softirq.c:645
 __do_softirq kernel/softirq.c:679 [inline]
 invoke_softirq kernel/softirq.c:519 [inline]
 __irq_exit_rcu+0xcb/0x220 kernel/softirq.c:758
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:775
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:kasan_check_byte include/linux/kasan.h:402 [inline]
RIP: 0010:lock_acquire+0x75/0x350 kernel/locking/lockdep.c:5916
Code: a3 05 27 04 d7 0f 73 0d e8 f8 34 09 00 84 c0 0f 84 e2 01 00 00 83 3d 19 35 d7 0f 00 0f 84 e9 00 00 00 48 8b b4 24 88 00 00 00 <4c> 89 e7 e8 03 5d 95 00 83 3d fc 34 d7 0f 00 0f 84 e4 00 00 00 65
RSP: 0000:ffffc9000324ef88 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 8000000000000001
RDX: 0000000000000000 RSI: ffffffff817811fc RDI: ffffffff8c6dd820
RBP: 1ffff92000649e20 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc9000324ede0 R11: ffffffff81b2c450 R12: ffffffff8fd5c8a0
R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000000
 rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
 unwind_next_frame+0xac/0x2550 arch/x86/kernel/unwind_orc.c:495
 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
 __call_rcu_common kernel/rcu/tree.c:3181 [inline]
 call_rcu+0xee/0x8b0 kernel/rcu/tree.c:3301
 slab_free_hook mm/slub.c:2712 [inline]
 slab_free mm/slub.c:6509 [inline]
 kmem_cache_free+0x471/0x650 mm/slub.c:6636
 anon_vma_free mm/rmap.c:137 [inline]
 __put_anon_vma+0x12b/0x2d0 mm/rmap.c:2974
 put_anon_vma mm/internal.h:290 [inline]
 unlink_anon_vmas+0x544/0x720 mm/rmap.c:540
 free_pgtables+0x663/0xb70 mm/memory.c:401
 exit_mmap+0x4aa/0x9f0 mm/mmap.c:1327
 __mmput+0x118/0x420 kernel/fork.c:1193
 copy_process+0x2f5f/0x4400 kernel/fork.c:2609
 kernel_clone+0x2d7/0x940 kernel/fork.c:2771
 __do_sys_clone kernel/fork.c:2913 [inline]
 __se_sys_clone kernel/fork.c:2897 [inline]
 __x64_sys_clone+0x1b6/0x230 kernel/fork.c:2897
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdd5e99e1d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fdd5f7ccfd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007fdd5ec26090 RCX: 00007fdd5e99e1d9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020102400
RBP: 00007fdd5ea35888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007fdd5ec26128 R14: 00007fdd5ec26090 R15: 00007ffe4f134c08
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 7822 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:check_kcov_mode kernel/kcov.c:190 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x4f/0x80 kernel/kcov.c:213
Code: 01 00 0f 81 fe 00 01 00 00 40 0f 95 c6 81 fa 00 00 00 10 0f 93 c2 40 08 f2 75 35 83 b9 44 17 00 00 00 74 2c 8b 91 18 17 00 00 <83> fa 02 75 21 48 8b 91 20 17 00 00 48 8b 32 48 8d 7e 01 8b 89 1c
RSP: 0000:ffffc900046af718 EFLAGS: 00000246
RAX: ffffffff81bbc688 RBX: ffff8880b8443708 RCX: ffff88802ba30000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900046af870 R08: ffffffff917a6b7f R09: 1ffffffff22f4d6f
R10: dffffc0000000000 R11: fffffbfff22f4d70 R12: 1ffff110170886e1
R13: dffffc0000000000 R14: 1ffff110057462b3 R15: 0000000000000000
FS:  00007f810459f880(0000) GS:ffff888123bc0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055fc388e1f28 CR3: 000000003419e000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000008d24
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 csd_lock_wait kernel/smp.c:363 [inline]
 smp_call_function_many_cond+0x1148/0x1500 kernel/smp.c:1002
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline]
 flush_tlb_mm_range+0x8ff/0x1090 arch/x86/mm/tlb.c:1435
 flush_tlb_page arch/x86/include/asm/tlbflush.h:352 [inline]
 ptep_clear_flush+0x120/0x170 mm/pgtable-generic.c:104
 wp_page_copy mm/memory.c:4073 [inline]
 do_wp_page+0x3c5c/0x4b80 mm/memory.c:4472
 handle_pte_fault mm/memory.c:6582 [inline]
 __handle_mm_fault mm/memory.c:6707 [inline]
 handle_mm_fault+0x15d7/0x3750 mm/memory.c:6876
 do_user_addr_fault+0xa4f/0x1340 arch/x86/mm/fault.c:1343
 handle_page_fault arch/x86/mm/fault.c:1483 [inline]
 exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1536
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595
RIP: 0033:0x7f8103eb5b69
Code: 10 48 81 f9 ff 03 00 00 76 28 48 8b 57 20 48 85 d2 74 1f 48 3b 7a 28 75 76 48 8b 4f 28 48 3b 79 20 75 6c 48 83 78 20 00 74 17 <48> 89 4a 28 48 89 51 20 48 83 c4 08 c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffeab5c9b00 EFLAGS: 00010206
RAX: 00007f8103ff21f0 RBX: 00000000000027c0 RCX: 000055fc388e1f00
RDX: 000055fc388e1f00 RSI: 00007f8103ff21f0 RDI: 000055fc388e1f00
RBP: 00007f8103ff1ac0 R08: 00000000000027c0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000055fc388df770
R13: 00007f8103ff1ac0 R14: 00000000000027c0 R15: 00007f8103ff1ac0
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/11 15:06 bpf ff47652a4b66 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-bpf-kasan-gce BUG: soft lockup in trace_call_bpf
* Struck through repros no longer work on HEAD.