syzbot


INFO: rcu detected stall in __put_task_struct

Status: auto-closed as invalid on 2021/11/01 17:33
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 486d, last: 486d
similar bugs (1):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in __put_task_struct (2) 1 361d 361d 0/24 closed as invalid on 2022/02/08 10:10

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1):
	(detected by 0, t=10502 jiffies, g=239173, q=97)
rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295075983-4295065481), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g239173 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=92029
rcu: rcu_preempt kthread starved for 10502 jiffies! g239173 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:26384 pid:   14 ppid:     2 flags:0x00004000
Call Trace:
 context_switch kernel/sched/core.c:4683 [inline]
 __schedule+0xc07/0x11f0 kernel/sched/core.c:5940
 schedule+0x14b/0x210 kernel/sched/core.c:6019
 schedule_timeout+0x1aa/0x2f0 kernel/time/timer.c:1879
 rcu_gp_fqs_loop kernel/rcu/tree.c:1996 [inline]
 rcu_gp_kthread+0x10fd/0x1720 kernel/rcu/tree.c:2169
 kthread+0x453/0x480 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 19 Comm: ksoftirqd/1 Not tainted 5.14.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:163 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0xd/0x60 kernel/kcov.c:197
Code: 00 00 48 c7 c7 a0 42 75 8c e8 7f 38 49 00 c3 cc cc cc cc cc cc cc cc cc cc cc cc cc cc 48 8b 04 24 65 48 8b 0c 25 80 ef 01 00 <65> 8b 15 c4 ca 81 7e f7 c2 00 01 ff 00 74 11 f7 c2 00 01 00 00 74
RSP: 0018:ffffc90000dc0c78 EFLAGS: 00000082
RAX: ffffffff8829ad40 RBX: 0000000000000000 RCX: ffff88801241d4c0
RDX: 0000000080010100 RSI: 0000000000000000 RDI: ffff88802f006b40
RBP: ffffc90000dc0e78 R08: ffffffff816f508b R09: fffffbfff1b74bee
R10: fffffbfff1b74bee R11: 0000000000000000 R12: dffffc0000000000
R13: ffff88802f006b40 R14: 1ffff11002483bd3 R15: ffff88802f006b40
FS:  0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2bc23000 CR3: 0000000074ba6000 CR4: 00000000001526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 advance_sched+0x20/0x930 net/sched/sch_taprio.c:702
 __run_hrtimer kernel/time/hrtimer.c:1537 [inline]
 __hrtimer_run_queues+0x50b/0xa60 kernel/time/hrtimer.c:1601
 hrtimer_interrupt+0x3b3/0x1040 kernel/time/hrtimer.c:1663
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline]
 __sysvec_apic_timer_interrupt+0xf9/0x270 arch/x86/kernel/apic/apic.c:1106
 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1100
 </IRQ>
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:yama_ptracer_del+0x9b/0x2e0 include/linux/rcupdate.h:688
Code: 6f d7 09 01 48 c7 c7 e0 eb 8c 8a be b1 02 00 00 48 c7 c2 20 ec 8c 8a e8 c3 05 93 fd 48 c7 c0 00 05 cb 8c 48 8b 1d 75 61 fb 08 <49> be 00 00 00 00 00 fc ff df 48 39 c3 0f 84 3b 01 00 00 4c 8d 6b
RSP: 0018:ffffc90000d979f8 EFLAGS: 00000246
RAX: ffffffff8ccb0500 RBX: ffffffff8ccb0500 RCX: ffff88801241d4c0
RDX: 0000000080000100 RSI: 0000000000000101 RDI: 0000000000000000
RBP: ffffc90000d97cb0 R08: dffffc0000000000 R09: fffffbfff1f5e5b1
R10: fffffbfff1f5e5b1 R11: 0000000000000000 R12: dffffc0000000000
R13: ffff888016ba30e8 R14: ffff888016ba1c40 R15: dffffc0000000000
 security_task_free+0x4d/0xc0 security/security.c:1654
 __put_task_struct+0xf5/0x3a0 kernel/fork.c:740
 rcu_do_batch kernel/rcu/tree.c:2550 [inline]
 rcu_core+0x906/0x14b0 kernel/rcu/tree.c:2785
 __do_softirq+0x372/0x783 kernel/softirq.c:558
 run_ksoftirqd+0xa2/0x100 kernel/softirq.c:920
 smpboot_thread_fn+0x533/0x9d0 kernel/smpboot.c:164
 kthread+0x453/0x480 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-smack-root 2021/08/03 17:24 upstream c500bee1c5b2 6c236867 .config log report info INFO: rcu detected stall in __put_task_struct
* Struck through repros no longer work on HEAD.