syzbot


INFO: rcu detected stall in sys_mount (3)

Status: closed as invalid on 2019/12/04 14:04
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 936d, last: 935d
similar bugs (5):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in sys_mount (6) C inconclusive 76 61d 272d 0/22 upstream: reported C repro on 2021/09/27 18:50
upstream INFO: rcu detected stall in sys_mount (4) 2 844d 859d 0/22 auto-closed as invalid on 2020/06/02 15:48
upstream INFO: rcu detected stall in sys_mount (5) C done done 10 634d 655d 17/22 fixed on 2020/11/16 12:12
upstream INFO: rcu detected stall in sys_mount 1 1341d 1341d 0/22 closed as invalid on 2018/10/29 13:47
upstream INFO: rcu detected stall in sys_mount (2) 1 1292d 1292d 0/22 closed as dup on 2018/12/12 21:01

Sample crash report:
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (1 GPs behind) idle=b2e/1/0x4000000000000002 softirq=12450/12458 fqs=6 
	(t=10500 jiffies g=6653 q=557)
rcu: rcu_preempt kthread starved for 10487 jiffies! g6653 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    29032    10      2 0x80004000
Call Trace:
 context_switch kernel/sched/core.c:3385 [inline]
 __schedule+0x9a0/0xcc0 kernel/sched/core.c:4081
 schedule+0x181/0x210 kernel/sched/core.c:4155
 schedule_timeout+0x14f/0x240 kernel/time/timer.c:1895
 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline]
 rcu_gp_kthread+0xed8/0x1770 kernel/rcu/tree.c:1821
 kthread+0x332/0x350 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 1
CPU: 1 PID: 8247 Comm: syz-executor.0 Not tainted 5.4.0-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:77 [inline]
 dump_stack+0x1fb/0x318 lib/dump_stack.c:118
 nmi_cpu_backtrace+0xaf/0x1a0 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x174/0x290 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x10/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x15a/0x220 kernel/rcu/tree_stall.h:254
 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:529 [inline]
 rcu_pending kernel/rcu/tree.c:2827 [inline]
 rcu_sched_clock_irq+0xe25/0x1ad0 kernel/rcu/tree.c:2271
 update_process_times+0x12d/0x180 kernel/time/timer.c:1726
 tick_sched_handle kernel/time/tick-sched.c:167 [inline]
 tick_sched_timer+0x263/0x420 kernel/time/tick-sched.c:1310
 __run_hrtimer kernel/time/hrtimer.c:1514 [inline]
 __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1576
 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1638
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline]
 smp_apic_timer_interrupt+0x109/0x280 arch/x86/kernel/apic/apic.c:1135
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 </IRQ>
RIP: 0010:check_kcov_mode kernel/kcov.c:68 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x14/0x50 kernel/kcov.c:102
Code: 00 00 00 48 8b 3d 74 25 cd 07 48 89 de e8 64 02 3b 00 5b 5d c3 cc 48 8b 04 24 65 48 8b 0c 25 c0 1d 02 00 65 8b 15 b8 81 8b 7e <f7> c2 00 01 1f 00 75 2c 8b 91 80 13 00 00 83 fa 02 75 21 48 8b 91
RSP: 0018:ffffc900022675c8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffffffff81487433 RBX: 0000000000000000 RCX: ffff8880a4b6c040
RDX: 0000000000000001 RSI: 000000000003ffff RDI: 0000000000040000
RBP: ffffc900022675f0 R08: 000000000003a768 R09: ffffed101331aa97
R10: ffffed101331aa97 R11: 0000000000000000 R12: dffffc0000000000
R13: dffffc0000000000 R14: 00000000fffffffc R15: ffff8880998d54a8
 free_thread_stack+0x168/0x590 kernel/fork.c:280
 release_task_stack kernel/fork.c:440 [inline]
 put_task_stack+0xa3/0x130 kernel/fork.c:451
 finish_task_switch+0x3f1/0x550 kernel/sched/core.c:3256
 context_switch kernel/sched/core.c:3388 [inline]
 __schedule+0x9a8/0xcc0 kernel/sched/core.c:4081
 preempt_schedule_common kernel/sched/core.c:4236 [inline]
 preempt_schedule+0xdb/0x120 kernel/sched/core.c:4261
 ___preempt_schedule+0x16/0x18 arch/x86/entry/thunk_64.S:50
 vprintk_emit+0x36d/0x3a0 kernel/printk/printk.c:1997
 vprintk_default+0x28/0x30 kernel/printk/printk.c:2023
 vprintk_func+0x158/0x170 kernel/printk/printk_safe.c:386
 printk+0x62/0x8d kernel/printk/printk.c:2056
 kobject_uevent_env+0xc4/0x1210 lib/kobject_uevent.c:476
 kobject_uevent+0x1f/0x30 lib/kobject_uevent.c:641
 device_add+0xffd/0x1ad0 drivers/base/core.c:2460
 device_create_groups_vargs drivers/base/core.c:3134 [inline]
 device_create_vargs+0x1c8/0x220 drivers/base/core.c:3174
 bdi_register_va+0x78/0x590 mm/backing-dev.c:940
 super_setup_bdi_name+0xec/0x190 fs/super.c:1606
 fuse_bdi_init fs/fuse/inode.c:1033 [inline]
 fuse_fill_super_common+0x500/0xf60 fs/fuse/inode.c:1169
 fuse_fill_super+0x27a/0x330 fs/fuse/inode.c:1252
 vfs_get_super fs/super.c:1189 [inline]
 get_tree_nodev+0xb7/0x170 fs/super.c:1219
 fuse_get_tree+0x92/0xe0 fs/fuse/inode.c:1286
 vfs_get_tree+0x8b/0x2a0 fs/super.c:1545
 do_new_mount fs/namespace.c:2822 [inline]
 do_mount+0x16bb/0x24f0 fs/namespace.c:3142
 ksys_mount+0xcc/0x100 fs/namespace.c:3351
 __do_sys_mount fs/namespace.c:3365 [inline]
 __se_sys_mount fs/namespace.c:3362 [inline]
 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3362
 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45a679
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f0298150c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000000045a679
RDX: 0000000020000240 RSI: 0000000020000200 RDI: 0000000000000000
RBP: 000000000075bf20 R08: 0000000020000400 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f02981516d4
R13: 00000000004c79ea R14: 00000000004de828 R15: 00000000ffffffff

Crashes (6):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-smack-root 2019/12/04 05:41 upstream 76bb8b05960c ae13a849 .config log report
ci-upstream-kasan-gce-smack-root 2019/12/03 17:25 upstream 76bb8b05960c ae13a849 .config log report
ci-upstream-kasan-gce-smack-root 2019/12/03 16:07 upstream 76bb8b05960c ab342da3 .config log report
ci-upstream-kasan-gce-smack-root 2019/12/03 06:33 upstream 596cf45cbf6e ab342da3 .config log report
ci-upstream-kasan-gce-smack-root 2019/12/03 04:14 upstream 596cf45cbf6e ab342da3 .config log report
ci-upstream-kasan-gce-smack-root 2019/12/03 02:32 upstream 596cf45cbf6e ab342da3 .config log report