syzbot


INFO: task hung in do_fb_ioctl (2)

Status: auto-closed as invalid on 2022/05/22 20:52
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 284d, last: 284d
similar bugs (4):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: task hung in do_fb_ioctl 1 1058d 1058d 0/1 auto-closed as invalid on 2020/05/08 18:42
upstream INFO: task hung in do_fb_ioctl 47 848d 1056d 0/24 closed as dup on 2020/07/27 22:56
linux-4.14 INFO: task hung in do_fb_ioctl C error 24 737d 1096d 0/1 upstream: reported C repro on 2019/12/03 05:09
linux-4.19 INFO: task hung in do_fb_ioctl (2) C done 7 468d 883d 1/1 fixed on 2021/09/21 12:35

Sample crash report:
INFO: task syz-executor.2:9858 blocked for more than 143 seconds.
      Not tainted 5.17.0-rc5-syzkaller-00004-g038101e6b2cd #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.2  state:D stack:28816 pid: 9858 ppid:  9656 flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:4995 [inline]
 __schedule+0xa94/0x4910 kernel/sched/core.c:6304
 schedule+0xd2/0x260 kernel/sched/core.c:6377
 schedule_timeout+0x1db/0x2a0 kernel/time/timer.c:1857
 __down_common+0x2e0/0x420 kernel/locking/semaphore.c:224
 down+0x70/0x90 kernel/locking/semaphore.c:62
 console_lock+0x28/0x80 kernel/printk/printk.c:2524
 do_fb_ioctl+0x2e4/0x6c0 drivers/video/fbdev/core/fbmem.c:1110
 fb_ioctl+0xe7/0x150 drivers/video/fbdev/core/fbmem.c:1191
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f432a935059
RSP: 002b:00007f4329289168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f432aa48030 RCX: 00007f432a935059
RDX: 0000000020000040 RSI: 0000000000004601 RDI: 0000000000000003
RBP: 00007f432a98f08d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f432af7bb1f R14: 00007f4329289300 R15: 0000000000022000
 </TASK>
INFO: task syz-executor.5:9857 blocked for more than 143 seconds.
      Not tainted 5.17.0-rc5-syzkaller-00004-g038101e6b2cd #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.5  state:D stack:29560 pid: 9857 ppid:  9662 flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:4995 [inline]
 __schedule+0xa94/0x4910 kernel/sched/core.c:6304
 schedule+0xd2/0x260 kernel/sched/core.c:6377
 schedule_timeout+0x1db/0x2a0 kernel/time/timer.c:1857
 __down_common+0x2e0/0x420 kernel/locking/semaphore.c:224
 down+0x70/0x90 kernel/locking/semaphore.c:62
 console_lock+0x28/0x80 kernel/printk/printk.c:2524
 do_fb_ioctl+0x2e4/0x6c0 drivers/video/fbdev/core/fbmem.c:1110
 fb_ioctl+0xe7/0x150 drivers/video/fbdev/core/fbmem.c:1191
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f6778acc059
RSP: 002b:00007f67773de168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f6778bdf1d0 RCX: 00007f6778acc059
RDX: 0000000020000040 RSI: 0000000000004601 RDI: 0000000000000003
RBP: 00007f6778b2608d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6779112b1f R14: 00007f67773de300 R15: 0000000000022000
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/26:
 #0: ffffffff8bb845e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6460
4 locks held by kworker/u4:3/90:
2 locks held by getty/3269:
 #0: ffff8880234bd098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:244
 #1: ffffc90002b662e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xcf0/0x1230 drivers/tty/n_tty.c:2075
1 lock held by syz-executor.4/9756:

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 26 Comm: khungtaskd Not tainted 5.17.0-rc5-syzkaller-00004-g038101e6b2cd #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1e6/0x230 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xc1d/0xf50 kernel/hung_task.c:369
 kthread+0x2e9/0x3a0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 90 Comm: kworker/u4:3 Not tainted 5.17.0-rc5-syzkaller-00004-g038101e6b2cd #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
RIP: 0010:orc_ip arch/x86/kernel/unwind_orc.c:30 [inline]
RIP: 0010:__orc_find+0x6f/0xf0 arch/x86/kernel/unwind_orc.c:52
Code: 72 4d 4c 89 e0 48 29 e8 48 89 c2 48 c1 e8 3f 48 c1 fa 02 48 01 d0 48 d1 f8 48 8d 5c 85 00 48 89 d8 48 c1 e8 03 42 0f b6 14 38 <48> 89 d8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 48 48 63 03 48 01
RSP: 0018:ffffc90001a9f5f0 EFLAGS: 00000a03
RAX: 1ffffffff1c05fe5 RBX: ffffffff8e02ff2c RCX: ffffffff88e47375
RDX: 0000000000000000 RSI: ffffffff8ea2a7d8 RDI: ffffffff8e02ff2c
RBP: ffffffff8e02ff2c R08: ffffffff8ea2a7d8 R09: 0000000000000001
R10: fffff52000353eed R11: 0000000000088078 R12: ffffffff8e02ff2c
R13: ffffffff8e02ff2c R14: ffffffff8e02ff2c R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fab56298548 CR3: 000000000b88e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 orc_find arch/x86/kernel/unwind_orc.c:173 [inline]
 unwind_next_frame+0x32a/0x1ce0 arch/x86/kernel/unwind_orc.c:443
 arch_stack_walk+0x7d/0xe0 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:436 [inline]
 __kasan_slab_alloc+0x90/0xc0 mm/kasan/common.c:469
 kasan_slab_alloc include/linux/kasan.h:260 [inline]
 slab_post_alloc_hook mm/slab.h:732 [inline]
 slab_alloc_node mm/slub.c:3230 [inline]
 kmem_cache_alloc_node+0x2c3/0x4f0 mm/slub.c:3266
 __alloc_skb+0x215/0x340 net/core/skbuff.c:414
 __netdev_alloc_skb+0x73/0x400 net/core/skbuff.c:494
 __netdev_alloc_skb_ip_align include/linux/skbuff.h:2968 [inline]
 netdev_alloc_skb_ip_align include/linux/skbuff.h:2978 [inline]
 batadv_iv_ogm_aggregate_new+0x106/0x4e0 net/batman-adv/bat_iv_ogm.c:559
 batadv_iv_ogm_queue_add net/batman-adv/bat_iv_ogm.c:671 [inline]
 batadv_iv_ogm_schedule_buff+0x990/0x1430 net/batman-adv/bat_iv_ogm.c:834
 batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:869 [inline]
 batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:862 [inline]
 batadv_iv_send_outstanding_bat_ogm_packet+0x740/0x910 net/batman-adv/bat_iv_ogm.c:1713
 process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307
 worker_thread+0x657/0x1110 kernel/workqueue.c:2454
 kthread+0x2e9/0x3a0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
----------------
Code disassembly (best guess):
   0:	72 4d                	jb     0x4f
   2:	4c 89 e0             	mov    %r12,%rax
   5:	48 29 e8             	sub    %rbp,%rax
   8:	48 89 c2             	mov    %rax,%rdx
   b:	48 c1 e8 3f          	shr    $0x3f,%rax
   f:	48 c1 fa 02          	sar    $0x2,%rdx
  13:	48 01 d0             	add    %rdx,%rax
  16:	48 d1 f8             	sar    %rax
  19:	48 8d 5c 85 00       	lea    0x0(%rbp,%rax,4),%rbx
  1e:	48 89 d8             	mov    %rbx,%rax
  21:	48 c1 e8 03          	shr    $0x3,%rax
  25:	42 0f b6 14 38       	movzbl (%rax,%r15,1),%edx
* 2a:	48 89 d8             	mov    %rbx,%rax <-- trapping instruction
  2d:	83 e0 07             	and    $0x7,%eax
  30:	83 c0 03             	add    $0x3,%eax
  33:	38 d0                	cmp    %dl,%al
  35:	7c 04                	jl     0x3b
  37:	84 d2                	test   %dl,%dl
  39:	75 48                	jne    0x83
  3b:	48 63 03             	movslq (%rbx),%rax
  3e:	48                   	rex.W
  3f:	01                   	.byte 0x1

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce 2022/02/21 20:51 upstream 038101e6b2cd 6e821dbf .config log report info INFO: task hung in do_fb_ioctl
* Struck through repros no longer work on HEAD.