syzbot


INFO: rcu detected stall in sys_newlstat

Status: fixed on 2020/11/16 12:12
Reported-by: syzbot+60b38542a0dfb2e0f746@syzkaller.appspotmail.com
Fix commit: 1d0e850a49a5 afs: Fix cell removal
First crash: 686d, last: 686d

Cause bisection: failed (bisect log)

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


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: 0 PID: 30808 at kernel/sched/core.c:3013 rq_unlock kernel/sched/sched.h:1325 [inline]
WARNING: CPU: 0 PID: 30808 at kernel/sched/core.c:3013 try_invoke_on_locked_down_task+0x12d/0x270 kernel/sched/core.c:3019
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 30808 Comm: systemd-udevd Not tainted 5.9.0-rc6-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+0x1d6/0x29e lib/dump_stack.c:118
 panic+0x2c0/0x800 kernel/panic.c:231
 __warn+0x227/0x250 kernel/panic.c:600
 report_bug+0x1b1/0x2e0 lib/bug.c:198
 handle_bug+0x42/0x80 arch/x86/kernel/traps.c:234
 exc_invalid_op+0x16/0x40 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+0x12d/0x270 kernel/sched/sched.h:1325
Code: f8 48 c1 e8 03 42 8a 04 38 84 c0 0f 85 10 01 00 00 8b 74 24 18 48 89 ef e8 90 47 09 00 4c 89 ef e8 48 1c fb 06 e9 a4 00 00 00 <0f> 0b e9 2b ff ff ff 48 c7 c1 74 d5 af 89 80 e1 07 80 c1 03 38 c1
RSP: 0018:ffffc90000007c50 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff8880a9bb27c0 RCX: 16c6f9e9214ef600
RDX: ffffc90000007d00 RSI: ffffffff8162e8d0 RDI: ffff8880a8ada340
RBP: ffffffff8162e8d0 R08: dffffc0000000000 R09: fffffbfff12df8f9
R10: fffffbfff12df8f9 R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff896ff600 R14: ffff8880a8ada340 R15: dffffc0000000000
 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:3637 [inline]
 rcu_sched_clock_irq+0x12bc/0x1eb0 kernel/rcu/tree.c:2519
 update_process_times+0x130/0x1b0 kernel/time/timer.c:1710
 tick_sched_handle kernel/time/tick-sched.c:176 [inline]
 tick_sched_timer+0x25e/0x410 kernel/time/tick-sched.c:1328
 __run_hrtimer kernel/time/hrtimer.c:1524 [inline]
 __hrtimer_run_queues+0x42d/0x930 kernel/time/hrtimer.c:1588
 hrtimer_interrupt+0x373/0xd60 kernel/time/hrtimer.c:1650
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline]
 __sysvec_apic_timer_interrupt+0xf0/0x260 arch/x86/kernel/apic/apic.c:1097
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706
 </IRQ>
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline]
 sysvec_apic_timer_interrupt+0x94/0xf0 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:770 [inline]
RIP: 0010:slab_alloc mm/slab.c:3305 [inline]
RIP: 0010:__do_kmalloc mm/slab.c:3653 [inline]
RIP: 0010:__kmalloc+0x196/0x300 mm/slab.c:3664
Code: 7c 24 20 48 8b 7c 24 10 f7 c7 00 02 00 00 74 0a e8 8f 65 c6 ff 48 8b 7c 24 10 48 83 3d 4a ac b8 07 00 0f 84 63 01 00 00 57 9d <0f> 1f 44 00 00 41 0f 18 0f e9 25 00 00 00 89 d8 c1 e8 08 83 e0 01
RSP: 0018:ffffc900053d7b60 EFLAGS: 00000282
RAX: 000000000000ae2f RBX: 0000000000000c40 RCX: ffff88808ddc82c0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000282
RBP: ffff8880aa440900 R08: ffffffff817ad120 R09: ffffed1015488341
R10: ffffed1015488341 R11: 0000000000000000 R12: 0000000000001000
R13: 0000000000000c40 R14: ffffffff838566e8 R15: ffff88806e032000
 kmalloc include/linux/slab.h:559 [inline]
 tomoyo_realpath_from_path+0xd8/0x630 security/tomoyo/realpath.c:254
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0x17d/0x740 security/tomoyo/file.c:822
 security_inode_getattr+0xc0/0x140 security/security.c:1278
 vfs_getattr fs/stat.c:121 [inline]
 vfs_statx+0x118/0x380 fs/stat.c:206
 vfs_lstat include/linux/fs.h:3178 [inline]
 __do_sys_newlstat fs/stat.c:374 [inline]
 __se_sys_newlstat fs/stat.c:368 [inline]
 __x64_sys_newlstat+0x81/0xd0 fs/stat.c:368
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f753b78f335
Code: 69 db 2b 00 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 83 ff 01 48 89 f0 77 30 48 89 c7 48 89 d6 b8 06 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 03 f3 c3 90 48 8b 15 31 db 2b 00 f7 d8 64 89
RSP: 002b:00007ffe76fa30f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000006
RAX: ffffffffffffffda RBX: 00005620599f5de0 RCX: 00007f753b78f335
RDX: 00007ffe76fa3270 RSI: 00007ffe76fa3270 RDI: 00005620599e0d80
RBP: 00007ffe76fa3270 R08: 0000562058300670 R09: 00000000000001b0
R10: 0000562058300d0c R11: 0000000000000246 R12: 00007ffe76fa31c0
R13: 0000000000000000 R14: 0000000000000003 R15: 000000000000000e
Shutting down cpus with NMI
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-smack-root 2020/09/23 05:12 upstream eff48ddeab78 3e8f6c27 .config log report syz C