syzbot

 sign-in | mailing list | source | docs
🐞 Open [654] 🐞 Fixed [37] 🐞 Invalid [326] ⬇ Missing Backports [56] 📈 Kernel Health 📈 Bugs/Month 📈 Bug Lifetimes 📈 Fuzzing 📈 Crashes 💬 Send us feedback

INFO: rcu detected stall in sys_symlinkat (3)

Status: upstream: reported on 2024/05/23 05:25
Reported-by: syzbot+06c309653e18d83baf54@syzkaller.appspotmail.com
First crash: 27d, last: 2d01h
▶ ▼ Similar bugs (9)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in sys_symlinkat (3) ext4 3 326d 379d 0/27 auto-obsoleted due to no activity on 2023/10/26 22:46
linux-5.15 INFO: rcu detected stall in sys_symlinkat 1 390d 390d 0/3 auto-obsoleted due to no activity on 2023/09/03 15:54
linux-6.1 INFO: rcu detected stall in sys_symlinkat (2) 1 174d 174d 0/3 auto-obsoleted due to no activity on 2024/04/06 00:16
upstream INFO: rcu detected stall in sys_symlinkat kvm 5 659d 759d 0/27 auto-obsoleted due to no activity on 2022/11/28 07:06
linux-6.1 INFO: rcu detected stall in sys_symlinkat 1 419d 419d 0/3 auto-obsoleted due to no activity on 2023/08/23 09:07
upstream INFO: rcu detected stall in sys_symlinkat (2) ext4 lsm 2 472d 565d 0/27 auto-obsoleted due to no activity on 2023/06/03 10:14
upstream INFO: rcu detected stall in sys_symlinkat (4) ext4 1 203d 203d 0/27 auto-obsoleted due to no activity on 2024/02/27 04:07
linux-5.15 INFO: rcu detected stall in sys_symlinkat (2) 1 199d 199d 0/3 auto-obsoleted due to no activity on 2024/03/12 11:22
android-5-15 BUG: soft lockup in sys_symlinkat 12 23d 65d 0/2 premoderation: reported on 2024/04/15 06:45

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=6eb/1/0x4000000000000000 softirq=21695/21696 fqs=0 
	(detected by 1, t=10502 jiffies, g=28857, q=22)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 7553 Comm: syz-executor.4 Not tainted 5.15.161-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
RIP: 0010:rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:331 [inline]
RIP: 0010:rcu_is_watching+0xc/0xa0 kernel/rcu/tree.c:1123
Code: 2a 2b b3 08 41 f7 c4 00 02 00 00 75 b4 eb b3 e8 0a 2b b3 08 66 2e 0f 1f 84 00 00 00 00 00 41 57 41 56 53 65 ff 05 5c 5d 97 7e <e8> af 3e b3 08 89 c3 83 f8 08 73 72 49 bf 00 00 00 00 00 fc ff df
RSP: 0018:ffffc90000007ac0 EFLAGS: 00000087
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8162a9bc
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8de46c28
RBP: ffffc90000007c28 R08: dffffc0000000000 R09: fffffbfff1bc8d86
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000000f64
R13: dffffc0000000000 R14: 0000000000000000 R15: dffffc0000000000
FS:  0000555555724480(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020089000 CR3: 0000000077a8e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 trace_lock_acquire include/trace/events/lock.h:13 [inline]
 lock_acquire+0xdd/0x4f0 kernel/locking/lockdep.c:5594
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162
 debug_object_deactivate+0x63/0x380 lib/debugobjects.c:748
 debug_hrtimer_deactivate kernel/time/hrtimer.c:425 [inline]
 debug_deactivate+0x1b/0x1e0 kernel/time/hrtimer.c:481
 __run_hrtimer kernel/time/hrtimer.c:1654 [inline]
 __hrtimer_run_queues+0x31d/0xcf0 kernel/time/hrtimer.c:1750
 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1812
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1085 [inline]
 __sysvec_apic_timer_interrupt+0x139/0x470 arch/x86/kernel/apic/apic.c:1102
 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1096
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:ext4_dir_rec_len fs/ext4/ext4.h:2373 [inline]
RIP: 0010:ext4_insert_dentry+0x59/0x6c0 fs/ext4/namei.c:2139
Code: 8d 5f 06 48 89 d8 48 c1 e8 03 42 0f b6 04 20 84 c0 0f 85 18 04 00 00 44 0f b6 23 45 8d 6c 24 0b 48 85 ed 48 89 6c 24 20 74 4b <e8> 32 f2 5c ff 48 8d 5d 0c 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00
RSP: 0018:ffffc90003607920 EFLAGS: 00000286
RAX: 0000000000000000 RBX: ffff88805d8e501e RCX: ffff888056008000
RDX: 0000000000000000 RSI: ffff88805e08f048 RDI: ffff8880569c82a0
RBP: ffff8880569c82a0 R08: ffffc90003607b60 R09: fffffbfff1bc8d86
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000006
R13: 0000000000000011 R14: ffffc90003607b60 R15: ffff88805d8e5018
 add_dirent_to_buf+0x384/0x7d0 fs/ext4/namei.c:2197
 ext4_add_entry+0x932/0x12b0 fs/ext4/namei.c:2448
 ext4_add_nondir+0x8d/0x290 fs/ext4/namei.c:2796
 ext4_symlink+0x916/0xed0 fs/ext4/namei.c:3452
 vfs_symlink+0x247/0x3d0 fs/namei.c:4429
 do_symlinkat+0x1fd/0x600 fs/namei.c:4458
 __do_sys_symlinkat fs/namei.c:4475 [inline]
 __se_sys_symlinkat fs/namei.c:4472 [inline]
 __x64_sys_symlinkat+0x95/0xa0 fs/namei.c:4472
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f27d3d0c6a7
Code: 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 0a 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc349dd8e8 EFLAGS: 00000206 ORIG_RAX: 000000000000010a
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f27d3d0c6a7
RDX: 00007f27d3d6a80d RSI: 00000000ffffff9c RDI: 00007ffc349dd9a0
RBP: 0000000000000001 R08: 0000000000000013 R09: 00007ffc349dd637
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 00007ffc349dd9a0 R15: 0000000000000001
 </TASK>
rcu: rcu_preempt kthread starved for 10502 jiffies! g28857 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:26816 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1f0 kernel/sched/core.c:6459
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:300
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 1
CPU: 1 PID: 7555 Comm: syz-executor.0 Not tainted 5.15.161-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_check_gp_kthread_starvation+0x1d2/0x240 kernel/rcu/tree_stall.h:487
 print_other_cpu_stall+0x137a/0x14d0 kernel/rcu/tree_stall.h:592
 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
 rcu_pending kernel/rcu/tree.c:3932 [inline]
 rcu_sched_clock_irq+0xa38/0x1150 kernel/rcu/tree.c:2619
 update_process_times+0x196/0x200 kernel/time/timer.c:1818
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x386/0x550 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1686 [inline]
 __hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1750
 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1812
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1085 [inline]
 __sysvec_apic_timer_interrupt+0x139/0x470 arch/x86/kernel/apic/apic.c:1102
 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1096
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline]
RIP: 0010:smp_call_function_many_cond+0xa93/0xd90 kernel/smp.c:969
Code: 04 03 84 c0 0f 85 84 00 00 00 45 8b 7d 00 44 89 fe 83 e6 01 31 ff e8 4c cf 0b 00 41 83 e7 01 75 07 e8 e1 cb 0b 00 eb 41 f3 90 <48> b8 00 00 00 00 00 fc ff df 0f b6 04 03 84 c0 75 11 41 f7 45 00
RSP: 0018:ffffc900035c7220 EFLAGS: 00000246
RAX: ffffffff81748f14 RBX: 1ffff11017348509 RCX: 0000000000040000
RDX: ffffc9000409a000 RSI: 000000000003ffff RDI: 0000000000040000
RBP: ffffc900035c7360 R08: ffffffff81748ee4 R09: fffffbfff1f7f21a
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: ffff8880b9a42848 R14: ffff8880b9b3b3c0 R15: 0000000000000001
 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1135
 __purge_vmap_area_lazy+0x294/0x1740 mm/vmalloc.c:1683
 _vm_unmap_aliases+0x453/0x4e0 mm/vmalloc.c:2107
 change_page_attr_set_clr+0x308/0x1050 arch/x86/mm/pat/set_memory.c:1740
 change_page_attr_clear arch/x86/mm/pat/set_memory.c:1797 [inline]
 set_memory_ro+0xa1/0xe0 arch/x86/mm/pat/set_memory.c:1943
 bpf_jit_binary_lock_ro include/linux/filter.h:891 [inline]
 bpf_int_jit_compile+0xbf57/0xc6e0 arch/x86/net/bpf_jit_comp.c:2372
 bpf_prog_select_runtime+0x6e2/0x9b0 kernel/bpf/core.c:1930
 bpf_prog_load+0x131c/0x1b60 kernel/bpf/syscall.c:2357
 __sys_bpf+0x343/0x670 kernel/bpf/syscall.c:4651
 __do_sys_bpf kernel/bpf/syscall.c:4755 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:4753 [inline]
 __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4753
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fb381be5f29
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb38075f0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007fb381d1cf80 RCX: 00007fb381be5f29
RDX: 000000000000002e RSI: 0000000020000080 RDI: 0000000000000005
RBP: 00007fb381c55074 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fb381d1cf80 R15: 00007ffe824d1178
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/06/17 17:36 linux-5.15.y 4878aadf2d15 1f11cfd7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_symlinkat
2024/05/23 05:24 linux-5.15.y 83655231580b 4d098039 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: rcu detected stall in sys_symlinkat
* Struck through repros no longer work on HEAD.