syzbot


INFO: rcu detected stall in sys_syslog

Status: upstream: reported on 2024/06/06 06:03
Reported-by: syzbot+91237475da3b0f66ae3b@syzkaller.appspotmail.com
First crash: 12d, last: 12d
Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in sys_syslog kernel 1 280d 280d 0/27 auto-obsoleted due to no activity on 2023/12/11 00:13
upstream INFO: rcu detected stall in sys_syslog (2) input usb syz 2 23d 118d 0/27 upstream: reported syz repro on 2024/02/20 16:45
linux-5.15 INFO: rcu detected stall in sys_syslog 2 21d 23d 0/3 upstream: reported on 2024/05/26 09:39
android-5-15 BUG: soft lockup in sys_syslog origin:lts C 10 23d 72d 0/2 upstream: reported C repro on 2024/04/07 08:50

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=2244/1/0x4000000000000000 softirq=18543/18575 fqs=0
	(detected by 0, t=10504 jiffies, g=21273, q=823 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 5847 Comm: syz-executor.0 Not tainted 6.1.92-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
RIP: 0010:kasan_check_range+0x6/0x290 mm/kasan/generic.c:188
Code: e8 8f b9 a9 08 31 c0 c3 0f 0b b8 ea ff ff ff c3 0f 0b b8 ea ff ff ff c3 cc cc cc cc cc cc cc cc cc cc cc cc 55 41 57 41 56 53 <b0> 01 48 85 f6 0f 84 9a 01 00 00 48 89 fd 48 01 f5 0f 82 5a 02 00
RSP: 0018:ffffc900001e0b98 EFLAGS: 00000046
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffffffff816bc524
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff91ef0450
RBP: ffffc900001e0cb8 R08: dffffc0000000000 R09: fffffbfff1ce712e
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: 1ffff9200003c184 R14: ffffc900001e0c40 R15: ffffffff91ef0450
FS:  0000555556b2a480(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbd10d886a8 CR3: 000000005d173000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 instrument_atomic_read include/linux/instrumented.h:72 [inline]
 atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline]
 queued_spin_is_locked include/asm-generic/qspinlock.h:57 [inline]
 debug_spin_unlock kernel/locking/spinlock_debug.c:100 [inline]
 do_raw_spin_unlock+0x54/0x8a0 kernel/locking/spinlock_debug.c:140
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:150 [inline]
 _raw_spin_unlock_irqrestore+0x7d/0x130 kernel/locking/spinlock.c:194
 debug_object_activate+0x2f9/0x4e0 lib/debugobjects.c:715
 debug_hrtimer_activate kernel/time/hrtimer.c:420 [inline]
 debug_activate kernel/time/hrtimer.c:475 [inline]
 enqueue_hrtimer+0x30/0x410 kernel/time/hrtimer.c:1084
 __run_hrtimer kernel/time/hrtimer.c:1703 [inline]
 __hrtimer_run_queues+0x728/0xe50 kernel/time/hrtimer.c:1750
 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1812
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1095 [inline]
 __sysvec_apic_timer_interrupt+0x156/0x580 arch/x86/kernel/apic/apic.c:1112
 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1106
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:653
RIP: 0010:check_kcov_mode kernel/kcov.c:175 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:236 [inline]
RIP: 0010:__sanitizer_cov_trace_switch+0x7c/0xe0 kernel/kcov.c:340
Code: c2 49 39 d2 74 71 4c 8b 74 d6 10 65 8b 05 34 dd 77 7e a9 00 01 ff 00 74 11 a9 00 01 00 00 74 de 41 83 bb 1c 16 00 00 00 74 d4 <41> 8b 83 f8 15 00 00 83 f8 03 75 c8 49 8b 8b 00 16 00 00 45 8b bb
RSP: 0018:ffffc900036bf618 EFLAGS: 00000246
RAX: 0000000080000000 RBX: 0000000000000004 RCX: 000000000000008b
RDX: 0000000000000011 RSI: ffffffff8e5d1e00 RDI: 0000000000000004
RBP: ffffc900036bf730 R08: 0000000000000001 R09: ffffffff8a8547a1
R10: 0000000000000012 R11: ffff8880163a0000 R12: ffffc900036bf992
R13: 0000000000000003 R14: 0000000000000012 R15: ffffffff8aecc5a1
 vsnprintf+0x191/0x1c70 lib/vsprintf.c:2761
 sprintf+0xd6/0x120 lib/vsprintf.c:3009
 print_caller kernel/printk/printk.c:1285 [inline]
 info_print_prefix+0x200/0x300 kernel/printk/printk.c:1302
 get_record_print_text_size kernel/printk/printk.c:1437 [inline]
 find_first_fitting_seq+0x3d3/0x580 kernel/printk/printk.c:1485
 syslog_print_all+0x1aa/0x7e0 kernel/printk/printk.c:1614
 do_syslog+0x79a/0x910 kernel/printk/printk.c:1693
 __do_sys_syslog kernel/printk/printk.c:1771 [inline]
 __se_sys_syslog kernel/printk/printk.c:1769 [inline]
 __x64_sys_syslog+0x78/0x90 kernel/printk/printk.c:1769
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f486d27cf69
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:00007fff965091e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000067
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f486d27cf69
RDX: 000000000000003f RSI: 00007fff965092d0 RDI: 0000000000000003
RBP: 00007fff965092d0 R08: 0000000000000010 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff965098b8
R13: 00007fff9650aedf R14: 0000000000000001 R15: 0000000000000001
 </TASK>
rcu: rcu_preempt kthread starved for 10504 jiffies! g21273 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:26680 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x142d/0x4550 kernel/sched/core.c:6558
 schedule+0xbf/0x180 kernel/sched/core.c:6634
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1965
 rcu_gp_fqs_loop+0x2d2/0x1150 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0xa3/0x3b0 kernel/rcu/tree.c:1905
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 4144 Comm: kworker/0:13 Not tainted 6.1.92-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Workqueue: events drain_vmap_area_work
RIP: 0010:csd_lock_wait kernel/smp.c:424 [inline]
RIP: 0010:smp_call_function_many_cond+0x1fb5/0x3460 kernel/smp.c:998
Code: e6 01 31 ff e8 ec 42 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 0a e8 77 3f 0b 00 e9 1b ff ff ff f3 90 42 0f b6 04 2b <84> c0 75 14 41 f7 07 01 00 00 00 0f 84 fe fe ff ff e8 55 3f 0b 00
RSP: 0018:ffffc9000abaf6c0 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 1ffff110173281b1 RCX: ffff888019f60000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000abafa90 R08: ffffffff817f4dc4 R09: fffffbfff2093846
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000800000000
R13: dffffc0000000000 R14: 0000000000000001 R15: ffff8880b9940d88
FS:  0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbd10bd4440 CR3: 000000000ce8e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 </IRQ>
 <TASK>
 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1166
 on_each_cpu include/linux/smp.h:71 [inline]
 flush_tlb_kernel_range+0x197/0x230 arch/x86/mm/tlb.c:1058
 __purge_vmap_area_lazy+0x157c/0x1720 mm/vmalloc.c:1774
 drain_vmap_area_work+0x3c/0xd0 mm/vmalloc.c:1803
 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292
 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/06/06 06:03 linux-6.1.y 88690811da69 121701b6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_syslog
* Struck through repros no longer work on HEAD.