syzbot

 sign-in | mailing list | source | docs
🐞 Open [1454]
≡ Subsystems
🐞 Fixed [6885]
🐞 Invalid [17897]
⬇ Missing Backports [224]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
Total Repo Heatmap Subsystems Heatmap
💬 Send us feedback

INFO: rcu detected stall in syscall_trace_enter (5)

Status: auto-obsoleted due to no activity on 2025/10/31 19:29
Subsystems: selinux mm
[Documentation on labels]
First crash: 182d, last: 178d
▶ ▼ Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in syscall_trace_enter (2) mm 1 1 2247d 2247d 0/29 closed as invalid on 2019/12/04 14:04
upstream INFO: rcu detected stall in syscall_trace_enter kernel 1 5 2668d 2692d 0/29 auto-closed as invalid on 2019/04/06 08:39
linux-6.6 INFO: rcu detected stall in syscall_trace_enter origin:lts-only 1 syz inconclusive 5 31d 194d 0/2 upstream: reported syz repro on 2025/07/17 08:48
upstream INFO: rcu detected stall in syscall_trace_enter (4) trace bpf 1 10 330d 530d 0/29 auto-obsoleted due to no activity on 2025/06/01 11:19
upstream INFO: rcu detected stall in syscall_trace_enter (3) kernel 1 1 670d 670d 0/29 auto-obsoleted due to no activity on 2024/06/26 05:41
linux-5.15 INFO: rcu detected stall in syscall_trace_enter origin:lts-only 1 C error 77 2d21h 277d 0/3 upstream: reported C repro on 2025/04/26 00:59

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=e7bc/1/0x4000000000000000 softirq=206384/206385 fqs=17
rcu: 	(detected by 0, t=10502 jiffies, g=198569, q=259 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 15612 Comm: syz.6.6410 Not tainted 6.16.0-syzkaller-11105-ga6923c06a3b2 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:__rb_erase_augmented include/linux/rbtree_augmented.h:240 [inline]
RIP: 0010:rb_erase+0x60c/0x1370 lib/rbtree.c:443
Code: c1 ea 03 80 3c 02 00 0f 85 e3 0b 00 00 48 89 19 e9 74 ff ff ff 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 80 3c 02 00 <0f> 85 ab 0b 00 00 49 8b 5d 00 48 83 fb 03 0f 86 40 01 00 00 48 b8
RSP: 0018:ffffc90000a08d90 EFLAGS: 00000046
RAX: dffffc0000000000 RBX: ffff888143b84340 RCX: ffff8880b8527dd0
RDX: 1ffff11028770868 RSI: ffff8880b8527dd0 RDI: ffff888143b84350
RBP: ffff8880b8527dd0 R08: 0000000000000006 R09: 0000000000000001
R10: ffff888143b84340 R11: 0000000000000000 R12: ffff8880b8527dd8
R13: ffff888143b84340 R14: 0000000000000000 R15: 0000000000000000
FS:  00007ff3cabe76c0(0000) GS:ffff8881247c8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2d51be CR3: 0000000044fc9000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000040020
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 rb_erase_cached include/linux/rbtree.h:126 [inline]
 timerqueue_del+0x83/0x150 lib/timerqueue.c:57
 __remove_hrtimer+0x99/0x290 kernel/time/hrtimer.c:1121
 __run_hrtimer kernel/time/hrtimer.c:1741 [inline]
 __hrtimer_run_queues+0x4f9/0xad0 kernel/time/hrtimer.c:1825
 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
 __sysvec_apic_timer_interrupt+0x10b/0x3f0 arch/x86/kernel/apic/apic.c:1056
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:unwind_next_frame+0x1592/0x20a0 arch/x86/kernel/unwind_orc.c:648
Code: 49 89 c0 49 c1 e8 03 41 0f b6 14 10 49 89 f8 41 83 e0 07 44 38 c6 41 0f 9e c0 40 84 f6 40 0f 95 c6 41 84 f0 0f 85 47 08 00 00 <83> e0 07 38 c2 40 0f 9e c6 84 d2 0f 95 c0 40 84 c6 0f 85 30 08 00
RSP: 0018:ffffc900055d7648 EFLAGS: 00000246
RAX: ffffffff91f61d21 RBX: 0000000000000001 RCX: ffffffff91f61d1e
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff91f61d20
RBP: ffffc900055d7700 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000002 R11: 00000000000a920a R12: ffffc900055d7708
R13: ffffc900055d76b8 R14: ffffc900055d7f58 R15: ffffc900055d76ec
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4365 [inline]
 __kmalloc_node_track_caller_noprof+0x221/0x510 mm/slub.c:4384
 kmemdup_noprof+0x29/0x60 mm/util.c:138
 kmemdup_noprof include/linux/fortify-string.h:765 [inline]
 sidtab_sid2str_get+0x17a/0x680 security/selinux/ss/sidtab.c:625
 sidtab_entry_to_string+0x33/0x110 security/selinux/ss/services.c:1316
 security_sid_to_context_core+0x35c/0x640 security/selinux/ss/services.c:1419
 selinux_secid_to_secctx security/selinux/hooks.c:6797 [inline]
 selinux_lsmprop_to_secctx+0xe4/0x1b0 security/selinux/hooks.c:6811
 security_lsmprop_to_secctx+0x94/0x260 security/security.c:4355
 audit_log_task_context+0x122/0x190 kernel/audit.c:2190
 audit_log_task+0x1c2/0x3f0 kernel/auditsc.c:2954
 audit_seccomp+0x79/0x290 kernel/auditsc.c:3004
 seccomp_log kernel/seccomp.c:1033 [inline]
 __seccomp_filter+0x7b6/0xea0 kernel/seccomp.c:1328
 __secure_computing+0x287/0x3b0 kernel/seccomp.c:1388
 syscall_trace_enter+0x89/0x240 kernel/entry/syscall-common.c:44
 syscall_enter_from_user_mode_work include/linux/entry-common.h:95 [inline]
 syscall_enter_from_user_mode include/linux/entry-common.h:125 [inline]
 do_syscall_64+0x347/0x4c0 arch/x86/entry/syscall_64.c:90
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff3c9d8eb69
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:00007ff3cabe70e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007ff3c9fb5fa8 RCX: 00007ff3c9d8eb69
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007ff3c9fb5fac
RBP: 00007ff3c9fb5fa0 R08: 00007ff3cabe8000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ff3c9fb5fac
R13: 0000000000000000 R14: 00007fff42d5c7a0 R15: 00007fff42d5c888
 </TASK>
rcu: rcu_preempt kthread starved for 10466 jiffies! g198569 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:27784 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7058
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2285
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 6728 Comm: kworker/u8:2 Not tainted 6.16.0-syzkaller-11105-ga6923c06a3b2 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:write_comp_data+0x8b/0x90 kernel/kcov.c:272
Code: 00 00 4a 8d 34 dd 28 00 00 00 48 39 f2 72 1b 48 83 c7 01 48 89 38 4c 89 44 30 e0 4c 89 4c 30 e8 4c 89 54 30 f0 4a 89 4c d8 20 <e9> 50 e9 d9 09 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3
RSP: 0018:ffffc9001117e860 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff8880b853fe80 RCX: ffffffff81af8aa1
RDX: ffff8880620e0000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: dffffc0000000000
R13: ffffed10170a7fd1 R14: 0000000000000001 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8881246c8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3f778f2b07 CR3: 0000000068408000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000001 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 csd_lock_wait kernel/smp.c:342 [inline]
 smp_call_function_many_cond+0xe21/0x1600 kernel/smp.c:877
 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1044
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline]
 flush_tlb_mm_range+0x4a0/0x17a0 arch/x86/mm/tlb.c:1451
 flush_tlb_page arch/x86/include/asm/tlbflush.h:324 [inline]
 ptep_clear_flush+0x136/0x180 mm/pgtable-generic.c:101
 page_vma_mkclean_one.constprop.0+0x3b4/0x7e0 mm/rmap.c:1059
 page_mkclean_one+0x196/0x260 mm/rmap.c:1100
 __rmap_walk_file+0x356/0x620 mm/rmap.c:2905
 rmap_walk_file+0x174/0x1f0 mm/rmap.c:2938
 rmap_walk mm/rmap.c:2949 [inline]
 folio_mkclean+0x251/0x3f0 mm/rmap.c:1132
 folio_clear_dirty_for_io+0x153/0x810 mm/page-writeback.c:2962
 mpage_submit_folio+0x84/0x2d0 fs/ext4/inode.c:2061
 mpage_process_page_bufs+0x47c/0x8d0 fs/ext4/inode.c:2191
 mpage_prepare_extent_to_map+0x79f/0x14d0 fs/ext4/inode.c:2736
 ext4_do_writepages+0xa11/0x3cf0 fs/ext4/inode.c:2877
 ext4_writepages+0x37a/0x7d0 fs/ext4/inode.c:3025
 do_writepages+0x277/0x600 mm/page-writeback.c:2634
 __writeback_single_inode+0x160/0xfb0 fs/fs-writeback.c:1680
 writeback_sb_inodes+0x60d/0xfa0 fs/fs-writeback.c:1976
 __writeback_inodes_wb+0xf8/0x2d0 fs/fs-writeback.c:2047
 wb_writeback+0x7f3/0xb70 fs/fs-writeback.c:2158
 wb_check_old_data_flush fs/fs-writeback.c:2262 [inline]
 wb_do_writeback fs/fs-writeback.c:2315 [inline]
 wb_workfn+0x8ca/0xbe0 fs/fs-writeback.c:2343
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/02 18:58 upstream a6923c06a3b2 7368264b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in syscall_trace_enter
2025/07/29 09:43 upstream ced1b9e0392d c4a95487 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in syscall_trace_enter
2025/08/02 19:21 linux-next 84b92a499e7e 7368264b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in syscall_trace_enter
* Struck through repros no longer work on HEAD.