INFO: rcu detected stall in inet_frag_destroy

Status: upstream: reported on 2026/03/29 06:28
Reported-by: syzbot+de6c09fe906b3915c85b@syzkaller.appspotmail.com
First crash: 121d, last: 1d04h
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: rcu detected stall in inet_frag_destroy 1 1 94d 94d 0/3 upstream: reported on 2026/04/25 20:23
android-54 BUG: soft lockup in inet_frag_destroy (2) 1 1 498d 498d 0/2 auto-obsoleted due to no activity on 2025/06/15 23:42
android-54 BUG: soft lockup in inet_frag_destroy 1 3 761d 770d 0/2 auto-obsoleted due to no activity on 2024/09/25 04:36

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 0-.... } 2630 jiffies s: 193913 root: 0x1/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4490 Comm: syz.0.10354 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:85 [inline]
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:102 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:128 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]
RIP: 0010:kasan_check_range+0x84/0x290 mm/kasan/generic.c:189
Code: 49 c1 e9 03 4b 8d 1c 21 49 89 df 4d 29 df 49 83 ff 10 7f 29 4d 85 ff 0f 84 38 01 00 00 4c 89 cb 48 f7 d3 4c 01 f3 41 80 3b 00 <0f> 85 86 01 00 00 49 ff c3 48 ff c3 75 ee e9 18 01 00 00 44 89 dd
RSP: 0018:ffffc90000006f50 EFLAGS: 00000046
RAX: 0000000000000001 RBX: ffffffffffffffff RCX: ffffffff816412d5
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90b0f248
RBP: ffffc900000071b0 R08: ffffffff90b0f24f R09: 1ffffffff2161e49
R10: dffffc0000000000 R11: fffffbfff2161e49 R12: dffffc0000000001
R13: ffff88802f673c00 R14: 1ffffffff2161e49 R15: 0000000000000001
FS:  00007f4fbb1936c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd13db556b8 CR3: 000000007e65c000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 instrument_atomic_read include/linux/instrumented.h:72 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 hlock_class kernel/locking/lockdep.c:228 [inline]
 lookup_chain_cache_add kernel/locking/lockdep.c:3742 [inline]
 validate_chain kernel/locking/lockdep.c:3798 [inline]
 __lock_acquire+0x1465/0x7c40 kernel/locking/lockdep.c:5063
 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676
 seqcount_lockdep_reader_access+0xcd/0x1d0 include/linux/seqlock.h:102
 ktime_get+0x31/0x270 kernel/time/timekeeping.c:846
 clockevents_program_event+0xe2/0x310 kernel/time/clockevents.c:326
 hrtimer_interrupt+0x561/0x980 kernel/time/hrtimer.c:1890
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
 __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1118
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:unwind_next_frame+0x7e/0x1fd0 arch/x86/kernel/unwind_orc.c:-1
Code: 8b 6b 38 49 89 df 49 c1 ef 03 43 0f b6 04 37 84 c0 0f 85 46 18 00 00 8b 03 85 c0 0f 84 24 17 00 00 89 44 24 64 48 89 6c 24 40 <4c> 89 6c 24 68 4c 89 64 24 48 4c 89 7c 24 10 bf 01 00 00 00 e8 09
RSP: 0018:ffffc90000007620 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffc900000076c8 RCX: 0000000000000100
RDX: dffffc0000000000 RSI: ffffffff8a2fd7dc RDI: ffffc90000007700
RBP: 1ffff92000000ee0 R08: ffffc90000007790 R09: 0000000000000021
R10: dffffc0000000000 R11: fffff52000000ee5 R12: ffffffff8a2fd7dc
R13: ffffc9000cdd7f20 R14: dffffc0000000000 R15: 1ffff92000000ed9
 arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x27/0x40 mm/kasan/generic.c:516
 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1729 [inline]
 slab_free_freelist_hook+0x133/0x1b0 mm/slub.c:1755
 slab_free mm/slub.c:3687 [inline]
 kmem_cache_free+0xf7/0x2a0 mm/slub.c:3709
 kfree_skb include/linux/skbuff.h:1252 [inline]
 inet_frag_rbtree_purge net/ipv4/inet_fragment.c:280 [inline]
 inet_frag_destroy+0x13d/0x230 net/ipv4/inet_fragment.c:300
 call_timer_fn+0x1ac/0x670 kernel/time/timer.c:1701
 expire_timers kernel/time/timer.c:1752 [inline]
 __run_timers+0x56c/0x810 kernel/time/timer.c:2023
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:2036
 handle_softirqs+0x291/0x910 kernel/softirq.c:596
 __do_softirq kernel/softirq.c:630 [inline]
 invoke_softirq kernel/softirq.c:470 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:finish_task_switch+0x267/0x8e0 kernel/sched/core.c:5125
Code: d6 08 85 c0 0f 84 38 01 00 00 48 85 db 0f 85 57 01 00 00 0f 1f 44 00 00 4c 89 e7 e8 93 b1 e0 08 e8 fe 16 2f 00 fb 4c 8b 65 b8 <49> 8d bc 24 f8 15 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0
RSP: 0018:ffffc9000cdd7640 EFLAGS: 00000286
RAX: d55cef19ef652b00 RBX: 0000000000000000 RCX: d55cef19ef652b00
RDX: dffffc0000000000 RSI: ffffffff8a8c17a0 RDI: ffffffff8adf5de0
RBP: ffffc9000cdd7690 R08: ffffffff90b0f247 R09: 1ffffffff2161e48
R10: dffffc0000000000 R11: fffffbfff2161e49 R12: ffff88802f673c00
R13: 1ffff110171c76fa R14: dffffc0000000000 R15: ffff8880b8e3b7d0
 context_switch kernel/sched/core.c:5249 [inline]
 __schedule+0x1087/0x4030 kernel/sched/core.c:6563
 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6732
 preempt_schedule+0xbc/0xd0 kernel/sched/core.c:6756
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
 on_each_cpu_cond_mask+0x71/0x80 kernel/smp.c:1166
 on_each_cpu include/linux/smp.h:71 [inline]
 text_poke_sync arch/x86/kernel/alternative.c:1574 [inline]
 text_poke_bp_batch+0x5ae/0x850 arch/x86/kernel/alternative.c:1836
 text_poke_flush arch/x86/kernel/alternative.c:1965 [inline]
 text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1972
 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146
 static_key_enable_cpuslocked+0x11f/0x240 kernel/jump_label.c:207
 static_key_enable+0x16/0x20 kernel/jump_label.c:220
 tracepoint_add_func+0x985/0xa10 kernel/tracepoint.c:363
 tracepoint_probe_register_prio kernel/tracepoint.c:513 [inline]
 tracepoint_probe_register+0x5a/0x90 kernel/tracepoint.c:533
 perf_trace_event_reg kernel/trace/trace_event_perf.c:129 [inline]
 perf_trace_event_init+0x41e/0x940 kernel/trace/trace_event_perf.c:202
 perf_trace_init+0x234/0x2d0 kernel/trace/trace_event_perf.c:226
 perf_tp_event_init+0x89/0x110 kernel/events/core.c:10119
 perf_try_init_event+0x12b/0x3d0 kernel/events/core.c:11634
 perf_init_event kernel/events/core.c:11698 [inline]
 perf_event_alloc+0xea0/0x21e0 kernel/events/core.c:11990
 __do_sys_perf_event_open kernel/events/core.c:12526 [inline]
 __se_sys_perf_event_open+0x701/0x1ec0 kernel/events/core.c:12418
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f4fba39de99
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:00007f4fbb193028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: ffffffffffffffda RBX: 00007f4fba625fa0 RCX: 00007f4fba39de99
RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000200000000080
RBP: 00007f4fba433eaf R08: 0000000000000000 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4fba626038 R14: 00007f4fba625fa0 R15: 00007fffd87801b8
 </TASK>

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/27 20:34 linux-6.1.y dc5c83b7f5f8 aae9036b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in inet_frag_destroy
2026/06/26 04:47 linux-6.1.y fdb6fcb41cc7 7ff32d8b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in inet_frag_destroy
2026/05/27 04:42 linux-6.1.y dcbcab9d7079 2b01f00e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in inet_frag_destroy
2026/05/22 04:59 linux-6.1.y c27210688955 70ae9b03 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in inet_frag_destroy
2026/03/29 06:27 linux-6.1.y 1989cd3d56e2 b5ceaad2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in inet_frag_destroy
* Struck through repros no longer work on HEAD.