syzbot


INFO: rcu detected stall in tty_ioctl (2)

Status: closed as invalid on 2022/02/08 10:00
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 395d, last: 386d
similar bugs (1):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in tty_ioctl C 12 1796d 1808d 4/24 fixed on 2018/02/14 17:52

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=10502 jiffies, g=463285, q=20)
rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295228269-4295217767), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10502 jiffies! g463285 f0x2 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:26576 pid:   14 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:4969 [inline]
 __schedule+0xb72/0x1460 kernel/sched/core.c:6250
 schedule+0x12b/0x1f0 kernel/sched/core.c:6323
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1881
 rcu_gp_fqs_loop+0x1fd/0x770 kernel/rcu/tree.c:1955
 rcu_gp_kthread+0xa5/0x350 kernel/rcu/tree.c:2128
 kthread+0x468/0x490 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 0
CPU: 0 PID: 30955 Comm: syz-executor.1 Not tainted 5.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1dc/0x2d8 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x45f/0x490 lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_check_gp_kthread_starvation+0x1ff/0x270 kernel/rcu/tree_stall.h:481
 print_other_cpu_stall kernel/rcu/tree_stall.h:586 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:729 [inline]
 rcu_pending kernel/rcu/tree.c:3878 [inline]
 rcu_sched_clock_irq+0x23d5/0x2bc0 kernel/rcu/tree.c:2597
 update_process_times+0x197/0x200 kernel/time/timer.c:1785
 tick_sched_handle kernel/time/tick-sched.c:226 [inline]
 tick_sched_timer+0x27d/0x420 kernel/time/tick-sched.c:1421
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4cb/0xa60 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x3b3/0x1040 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline]
 __sysvec_apic_timer_interrupt+0xf9/0x270 arch/x86/kernel/apic/apic.c:1103
 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1097
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x12/0x20
RIP: 0010:kasan_check_range+0x4/0x2f0 mm/kasan/generic.c:188
Code: c7 e8 f0 98 32 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 cc 41 57 41 56 <41> 55 41 54 53 b0 01 48 85 f6 0f 84 0d 02 00 00 48 89 fb 48 01 f3
RSP: 0018:ffffc90012ca76a8 EFLAGS: 00000246
RAX: 0000000000000002 RBX: ffff888038767438 RCX: ffffffff8486ddbc
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff888038767438
RBP: ffffc90012ca77d0 R08: ffffffff8486dda0 R09: ffffed10101343a1
R10: ffffed10101343a1 R11: 0000000000000000 R12: ffff8880809a1d18
R13: ffff8880809a1d18 R14: 1ffff110101343a0 R15: ffff8880809a1d00
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline]
 tty_throttled include/linux/tty.h:251 [inline]
 paste_selection+0x2dc/0x550 drivers/tty/vt/selection.c:400
 vt_ioctl+0x45d/0x3860 drivers/tty/vt/vt_ioctl.c:762
 tty_ioctl+0xfb2/0x17d0 drivers/tty/tty_io.c:2805
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f5829404ae9
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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f582697a188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f5829517f60 RCX: 00007f5829404ae9
RDX: 0000000020000000 RSI: 000000000000541c RDI: 0000000000000004
RBP: 00007f582945ef6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe4ca86fbf R14: 00007f582697a300 R15: 0000000000022000
 </TASK>
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	e8 f0 98 32 08       	callq  0x83298f5
   5:	31 c0                	xor    %eax,%eax
   7:	c3                   	retq
   8:	0f 0b                	ud2
   a:	b8 ea ff ff ff       	mov    $0xffffffea,%eax
   f:	c3                   	retq
  10:	0f 0b                	ud2
  12:	b8 ea ff ff ff       	mov    $0xffffffea,%eax
  17:	c3                   	retq
  18:	cc                   	int3
  19:	cc                   	int3
  1a:	cc                   	int3
  1b:	cc                   	int3
  1c:	cc                   	int3
  1d:	cc                   	int3
  1e:	cc                   	int3
  1f:	cc                   	int3
  20:	cc                   	int3
  21:	cc                   	int3
  22:	cc                   	int3
  23:	cc                   	int3
  24:	cc                   	int3
  25:	41 57                	push   %r15
  27:	41 56                	push   %r14
* 29:	41 55                	push   %r13 <-- trapping instruction
  2b:	41 54                	push   %r12
  2d:	53                   	push   %rbx
  2e:	b0 01                	mov    $0x1,%al
  30:	48 85 f6             	test   %rsi,%rsi
  33:	0f 84 0d 02 00 00    	je     0x246
  39:	48 89 fb             	mov    %rdi,%rbx
  3c:	48 01 f3             	add    %rsi,%rbx

Crashes (5):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-smack-root 2021/11/11 10:03 upstream debe436e77c7 75b04091 .config log report info INFO: rcu detected stall in tty_ioctl
ci-upstream-kasan-gce-root 2021/11/06 20:14 upstream d4439a1189f9 4c1be0be .config log report info INFO: rcu detected stall in tty_ioctl
ci-upstream-kasan-gce-root 2021/11/02 18:43 upstream cc0356d6a02e 17f3edd2 .config log report info INFO: rcu detected stall in tty_ioctl
ci-upstream-kasan-gce-selinux-root 2021/11/02 18:34 upstream bfc484fe6abb 17f3edd2 .config log report info INFO: rcu detected stall in tty_ioctl
ci-upstream-linux-next-kasan-gce-root 2021/11/06 07:19 linux-next 6a37ebbe07bf 4c1be0be .config log report info INFO: rcu detected stall in tty_ioctl
* Struck through repros no longer work on HEAD.