syzbot


INFO: rcu detected stall in sys_mount (5)

Status: fixed on 2020/11/16 12:12
Reported-by: syzbot+dc8c077c7091175cbdb1@syzkaller.appspotmail.com
Fix commit: 1d0e850a49a5 afs: Fix cell removal
First crash: 726d, last: 639d

Cause bisection: introduced by (bisect log) [merge commit]:
commit bc119dd954ba172554b4cc49db249c4fb62701e6
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date: Mon Mar 11 16:34:00 2019 +0000

  Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/ide

Crash: WARNING: proc registration bug in afs_manage_cell (log)
Repro: C syz .config

Fix bisection: fixed by (bisect log) :
commit 1d0e850a49a5b56f8f3cb51e74a11e2fedb96be6
Author: David Howells <dhowells@redhat.com>
Date: Fri Oct 16 12:21:14 2020 +0000

  afs: Fix cell removal

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 66d 277d 0/22 upstream: reported C repro on 2021/09/27 18:50
upstream INFO: rcu detected stall in sys_mount (4) 2 849d 864d 0/22 auto-closed as invalid on 2020/06/02 15:48
upstream INFO: rcu detected stall in sys_mount (3) 6 940d 941d 0/22 closed as invalid on 2019/12/04 14:04
upstream INFO: rcu detected stall in sys_mount 1 1346d 1346d 0/22 closed as invalid on 2018/10/29 13:47
upstream INFO: rcu detected stall in sys_mount (2) 1 1297d 1297d 0/22 closed as dup on 2018/12/12 21:01

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1):
------------[ cut here ]------------
WARNING: CPU: 1 PID: 8859 at kernel/sched/core.c:3013 rq_unlock kernel/sched/sched.h:1326 [inline]
WARNING: CPU: 1 PID: 8859 at kernel/sched/core.c:3013 try_invoke_on_locked_down_task+0x21d/0x2f0 kernel/sched/core.c:3019
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 8859 Comm: syz-executor153 Not tainted 5.9.0-rc7-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+0x198/0x1fd lib/dump_stack.c:118
 panic+0x382/0x7fb kernel/panic.c:231
 __warn.cold+0x20/0x4b kernel/panic.c:600
 report_bug+0x1bd/0x210 lib/bug.c:198
 handle_bug+0x38/0x90 arch/x86/kernel/traps.c:234
 exc_invalid_op+0x14/0x40 arch/x86/kernel/traps.c:254
 asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:536
RIP: 0010:try_invoke_on_locked_down_task+0x21d/0x2f0 kernel/sched/core.c:3013
Code: 45 31 f6 49 39 c0 74 3a 8b 74 24 38 49 8d 78 18 4c 89 04 24 e8 a4 e7 08 00 4c 8b 04 24 4c 89 c7 e8 28 9b d6 06 e9 20 ff ff ff <0f> 0b e9 7d fe ff ff 4c 89 ee 48 89 ef 41 ff d4 41 89 c6 e9 08 ff
RSP: 0018:ffffc90000da8be0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 1ffff920001b517e RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8162da10 RDI: ffff888094966040
RBP: ffff888094966040 R08: 0000000000000033 R09: ffffffff8a05ae03
R10: 0000000000000635 R11: 0000000000000001 R12: ffffffff8162da10
R13: ffffc90000da8d08 R14: ffff888094966040 R15: 0000000000000000
 rcu_print_task_stall kernel/rcu/tree_stall.h:267 [inline]
 print_other_cpu_stall kernel/rcu/tree_stall.h:475 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:634 [inline]
 rcu_pending kernel/rcu/tree.c:3639 [inline]
 rcu_sched_clock_irq.cold+0x97e/0xdfd kernel/rcu/tree.c:2521
 update_process_times+0x25/0xa0 kernel/time/timer.c:1710
 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:176
 tick_sched_timer+0x1d1/0x2a0 kernel/time/tick-sched.c:1328
 __run_hrtimer kernel/time/hrtimer.c:1524 [inline]
 __hrtimer_run_queues+0x1d5/0xfc0 kernel/time/hrtimer.c:1588
 hrtimer_interrupt+0x334/0x940 kernel/time/hrtimer.c:1650
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline]
 __sysvec_apic_timer_interrupt+0x147/0x5f0 arch/x86/kernel/apic/apic.c:1097
 asm_call_irq_on_stack+0xf/0x20
 </IRQ>
 __run_sysvec_on_irqstack arch/x86/include/asm/irq_stack.h:37 [inline]
 run_sysvec_on_irqstack_cond arch/x86/include/asm/irq_stack.h:89 [inline]
 sysvec_apic_timer_interrupt+0xb2/0xf0 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581
RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:29 [inline]
RIP: 0010:arch_atomic_fetch_add_unless include/linux/atomic-arch-fallback.h:1088 [inline]
RIP: 0010:arch_atomic_add_unless include/linux/atomic-arch-fallback.h:1113 [inline]
RIP: 0010:arch_atomic_inc_not_zero include/linux/atomic-arch-fallback.h:1129 [inline]
RIP: 0010:atomic_inc_not_zero include/asm-generic/atomic-instrumented.h:799 [inline]
RIP: 0010:afs_lookup_cell_rcu+0x524/0x720 fs/afs/cell.c:97
Code: 98 fe 49 8d 8c 24 a8 00 00 00 be 04 00 00 00 48 89 cd 48 89 cf 48 89 4c 24 30 e8 d7 ff d8 fe 48 89 e8 48 c1 e8 03 0f b6 14 18 <48> 89 e8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 b5 01 00 00 41
RSP: 0018:ffffc900038179b8 EFLAGS: 00000a02
RAX: 1ffff1101207ef15 RBX: dffffc0000000000 RCX: ffffffff82dde729
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8880903f78a8
RBP: ffff8880903f78a8 R08: 0000000000000001 R09: ffff8880903f78ab
R10: ffffed101207ef15 R11: 0000000000000000 R12: ffff8880903f7800
R13: ffff8880903f7a08 R14: 0000000000000000 R15: ffff8880903f7a10
 afs_lookup_cell+0x2ee/0x1440 fs/afs/cell.c:249
 afs_parse_source fs/afs/super.c:290 [inline]
 afs_parse_param+0x404/0x8c0 fs/afs/super.c:326
 vfs_parse_fs_param fs/fs_context.c:117 [inline]
 vfs_parse_fs_param+0x203/0x550 fs/fs_context.c:98
 vfs_parse_fs_string+0xe6/0x150 fs/fs_context.c:161
 generic_parse_monolithic+0x16f/0x1f0 fs/fs_context.c:201
 do_new_mount fs/namespace.c:2871 [inline]
 path_mount+0x133f/0x20a0 fs/namespace.c:3192
 do_mount fs/namespace.c:3205 [inline]
 __do_sys_mount fs/namespace.c:3413 [inline]
 __se_sys_mount fs/namespace.c:3390 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3390
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x447b2a
Code: b8 08 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 ed a2 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 ca a2 fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007ffdc34dfcc8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffdc34dfd10 RCX: 0000000000447b2a
RDX: 0000000020000000 RSI: 0000000020000040 RDI: 0000000000000000
RBP: 0000000000000000 R08: 00007ffdc34dfd10 R09: 0000000000000004
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402280
R13: 0000000000402310 R14: 0000000000000000 R15: 0000000000000000
Shutting down cpus with NMI
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (10):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-selinux-root 2020/09/30 18:53 upstream 02de58b24d2e 8516f6d3 .config log report syz C
ci-upstream-kasan-gce-selinux-root 2020/09/27 10:30 upstream a1bffa48745a 5dd8aee8 .config log report syz C
ci-upstream-kasan-gce-root 2020/09/26 18:27 upstream 7c7ec3226f5f 2d5ea0cb .config log report syz C
ci-upstream-kasan-gce-selinux-root 2020/09/21 21:13 upstream ba4f184e126b 9e1fa68e .config log report syz C
ci-upstream-kasan-gce-root 2020/09/09 07:16 upstream 612ab8ad6414 abf9ba4f .config log report syz C
ci-upstream-linux-next-kasan-gce-root 2020/09/27 18:26 linux-next d1d2220c7f39 5dd8aee8 .config log report syz C
ci-upstream-linux-next-kasan-gce-root 2020/09/22 20:52 linux-next e64997027d5f 3e8f6c27 .config log report syz C
ci-upstream-kasan-gce-selinux-root 2020/09/10 15:18 upstream 7fe10096c150 409809d8 .config log report
ci-upstream-kasan-gce-root 2020/09/09 05:01 upstream 612ab8ad6414 abf9ba4f .config log report
ci-upstream-kasan-gce-root 2020/07/04 22:27 upstream 7cc2a8ea1048 51095195 .config log report