syzbot


INFO: task hung in lo_ioctl (2)

Status: closed as invalid on 2022/02/08 09:40
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 385d, last: 379d
similar bugs (6):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-414 INFO: task hung in lo_ioctl syz 498 1313d 1335d 0/1 public: reported syz repro on 2019/04/10 16:14
linux-4.14 INFO: task hung in lo_ioctl 127 647d 1334d 0/1 auto-closed as invalid on 2021/06/25 19:54
android-44 INFO: task hung in lo_ioctl C 469 1127d 1333d 0/2 public: reported C repro on 2019/04/12 00:00
android-49 INFO: task hung in lo_ioctl C 1828 1133d 1333d 0/3 public: reported C repro on 2019/04/12 00:00
upstream INFO: task hung in lo_ioctl 47 1705d 1821d 12/24 fixed on 2019/03/06 07:43
linux-4.14 INFO: task hung in lo_ioctl (2) 1 33d 33d 0/1 upstream: reported on 2022/11/01 22:16

Sample crash report:
INFO: task syz-executor.2:29311 blocked for more than 143 seconds.
      Not tainted 5.16.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.2  state:D stack:25488 pid:29311 ppid:  7709 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:4972 [inline]
 __schedule+0xb72/0x1460 kernel/sched/core.c:6253
 schedule+0x12b/0x1f0 kernel/sched/core.c:6326
 blk_mq_freeze_queue_wait+0x105/0x190 block/blk-mq.c:178
 loop_change_fd drivers/block/loop.c:602 [inline]
 lo_ioctl+0x179f/0x1f40 drivers/block/loop.c:1560
 blkdev_ioctl+0x3ac/0x790 block/ioctl.c:609
 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: 0033:0x7fa2a6635ae9
RSP: 002b:00007fa2a3bab188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fa2a6748f60 RCX: 00007fa2a6635ae9
RDX: 0000000000000004 RSI: 0000000000004c06 RDI: 0000000000000003
RBP: 00007fa2a668ff6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffcd0f52f0f R14: 00007fa2a3bab300 R15: 0000000000022000
 </TASK>
INFO: task syz-executor.2:29316 blocked for more than 143 seconds.
      Not tainted 5.16.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.2  state:D stack:25968 pid:29316 ppid:  7709 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:4972 [inline]
 __schedule+0xb72/0x1460 kernel/sched/core.c:6253
 schedule+0x12b/0x1f0 kernel/sched/core.c:6326
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6385
 __mutex_lock_common+0xd1f/0x2590 kernel/locking/mutex.c:680
 __mutex_lock kernel/locking/mutex.c:740 [inline]
 mutex_lock_nested+0x1a/0x20 kernel/locking/mutex.c:792
 blkdev_get_by_dev+0xfc/0xb80 block/bdev.c:819
 blkdev_open+0x137/0x2f0 block/fops.c:501
 do_dentry_open+0x78b/0x1020 fs/open.c:822
 do_open fs/namei.c:3426 [inline]
 path_openat+0x2896/0x3660 fs/namei.c:3559
 do_filp_open+0x277/0x4f0 fs/namei.c:3586
 do_sys_openat2+0x13b/0x500 fs/open.c:1212
 do_sys_open fs/open.c:1228 [inline]
 __do_sys_openat fs/open.c:1244 [inline]
 __se_sys_openat fs/open.c:1239 [inline]
 __x64_sys_openat+0x243/0x290 fs/open.c:1239
 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: 0033:0x7fa2a65e8a04
RSP: 002b:00007fa2a3b89cc0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 00007fa2a65e8a04
RDX: 0000000000000000 RSI: 00007fa2a3b89d60 RDI: 00000000ffffff9c
RBP: 00007fa2a3b89d60 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00007ffcd0f52f0f R14: 00007fa2a3b8a300 R15: 0000000000022000
 </TASK>
INFO: task syz-executor.4:29315 blocked for more than 144 seconds.
      Not tainted 5.16.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.4  state:D stack:25072 pid:29315 ppid:  7737 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:4972 [inline]
 __schedule+0xb72/0x1460 kernel/sched/core.c:6253
 schedule+0x12b/0x1f0 kernel/sched/core.c:6326
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6385
 __mutex_lock_common+0xd1f/0x2590 kernel/locking/mutex.c:680
 __mutex_lock kernel/locking/mutex.c:740 [inline]
 mutex_lock_nested+0x1a/0x20 kernel/locking/mutex.c:792
 blkdev_get_by_dev+0xfc/0xb80 block/bdev.c:819
 blkdev_open+0x137/0x2f0 block/fops.c:501
 do_dentry_open+0x78b/0x1020 fs/open.c:822
 do_open fs/namei.c:3426 [inline]
 path_openat+0x2896/0x3660 fs/namei.c:3559
 do_filp_open+0x277/0x4f0 fs/namei.c:3586
 do_sys_openat2+0x13b/0x500 fs/open.c:1212
 do_sys_open fs/open.c:1228 [inline]
 __do_sys_openat fs/open.c:1244 [inline]
 __se_sys_openat fs/open.c:1239 [inline]
 __x64_sys_openat+0x243/0x290 fs/open.c:1239
 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: 0033:0x7f7682b22a04
RSP: 002b:00007f76800e4cc0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 00007f7682b22a04
RDX: 0000000000000000 RSI: 00007f76800e4d60 RDI: 00000000ffffff9c
RBP: 00007f76800e4d60 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00007ffd16c8054f R14: 00007f76800e5300 R15: 0000000000022000
 </TASK>
INFO: task syz-executor.4:29389 blocked for more than 144 seconds.
      Not tainted 5.16.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.4  state:D stack:27088 pid:29389 ppid:  7737 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:4972 [inline]
 __schedule+0xb72/0x1460 kernel/sched/core.c:6253
 schedule+0x12b/0x1f0 kernel/sched/core.c:6326
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6385
 __mutex_lock_common+0xd1f/0x2590 kernel/locking/mutex.c:680
 __mutex_lock kernel/locking/mutex.c:740 [inline]
 mutex_lock_nested+0x1a/0x20 kernel/locking/mutex.c:792
 blkdev_get_by_dev+0xfc/0xb80 block/bdev.c:819
 blkdev_open+0x137/0x2f0 block/fops.c:501
 do_dentry_open+0x78b/0x1020 fs/open.c:822
 do_open fs/namei.c:3426 [inline]
 path_openat+0x2896/0x3660 fs/namei.c:3559
 do_filp_open+0x277/0x4f0 fs/namei.c:3586
 do_sys_openat2+0x13b/0x500 fs/open.c:1212
 do_sys_open fs/open.c:1228 [inline]
 __do_sys_openat fs/open.c:1244 [inline]
 __se_sys_openat fs/open.c:1239 [inline]
 __x64_sys_openat+0x243/0x290 fs/open.c:1239
 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: 0033:0x7f7682b22a04
RSP: 002b:00007f76800a2cc0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 00007f7682b22a04
RDX: 0000000000000000 RSI: 00007f76800a2d60 RDI: 00000000ffffff9c
RBP: 00007f76800a2d60 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00007ffd16c8054f R14: 00007f76800a3300 R15: 0000000000022000
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8cb1dc00 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by systemd-udevd/2973:
 #0: ffff88801abc4118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0xfc/0xb80 block/bdev.c:819
 #1: ffff88814748fb60 (&lo->lo_mutex){+.+.}-{3:3}, at: lo_open+0x68/0x100 drivers/block/loop.c:1733
1 lock held by in:imklog/6214:
2 locks held by agetty/6200:
 #0: ffff88801dafa098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002fb32e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6c5/0x1c60 drivers/tty/n_tty.c:2113
1 lock held by syz-executor.4/29177:
 #0: ffff88801abc4118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xfa/0x7b0 block/bdev.c:914
1 lock held by syz-executor.2/29311:
 #0: ffff88814748fb60 (&lo->lo_mutex){+.+.}-{3:3}, at: loop_global_lock_killable drivers/block/loop.c:114 [inline]
 #0: ffff88814748fb60 (&lo->lo_mutex){+.+.}-{3:3}, at: loop_change_fd drivers/block/loop.c:576 [inline]
 #0: ffff88814748fb60 (&lo->lo_mutex){+.+.}-{3:3}, at: lo_ioctl+0xf78/0x1f40 drivers/block/loop.c:1560
1 lock held by syz-executor.2/29316:
 #0: ffff88801abc4118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0xfc/0xb80 block/bdev.c:819
1 lock held by syz-executor.4/29315:
 #0: ffff88801abc4118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0xfc/0xb80 block/bdev.c:819
1 lock held by syz-executor.4/29389:
 #0: ffff88801abc4118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0xfc/0xb80 block/bdev.c:819

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.16.0-rc1-syzkaller #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+0x1dc/0x2d8 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x45f/0x490 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xc82/0xcd0 kernel/hung_task.c:295
 kthread+0x468/0x490 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 2963 Comm: systemd-journal Not tainted 5.16.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:get_stack_info+0x3c/0xf0
Code: f5 48 85 f6 74 07 48 85 ff 75 10 eb 4e 65 48 8b 2c 25 c0 6f 02 00 48 85 ff 74 40 48 89 ee 48 89 da e8 38 e1 e2 08 84 c0 74 31 <45> 31 ff 4d 85 f6 74 35 4d 8b 2e 44 8b 23 49 83 fc 40 73 50 4d 0f
RSP: 0018:ffffc9000207f840 EFLAGS: 00000202
RAX: 000000000207f901 RBX: ffffc9000207f8e0 RCX: ffffc90002078000
RDX: ffffc9000207f8e0 RSI: ffffc90002080000 RDI: ffffc9000207f878
RBP: ffff88807b7f5700 R08: dffffc0000000000 R09: ffffc9000207f8e0
R10: fffff5200040ff28 R11: 0000000000000000 R12: ffffc9000207f900
R13: ffffc9000207f908 R14: ffffc9000207f900 R15: 1ffff9200040ff21
FS:  00007fe24c9598c0(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe247fef000 CR3: 000000001940f000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __unwind_start+0x46b/0x750 arch/x86/kernel/unwind_orc.c:681
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0xdc/0x140 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x11b/0x1e0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 __kasan_slab_alloc+0xb6/0xf0 mm/kasan/common.c:467
 kasan_slab_alloc include/linux/kasan.h:259 [inline]
 slab_post_alloc_hook mm/slab.h:519 [inline]
 slab_alloc_node mm/slub.c:3234 [inline]
 slab_alloc mm/slub.c:3242 [inline]
 kmem_cache_alloc+0x1c9/0x310 mm/slub.c:3247
 getname_flags+0xba/0x650 fs/namei.c:138
 do_sys_openat2+0xd2/0x500 fs/open.c:1206
 do_sys_open fs/open.c:1228 [inline]
 __do_sys_open fs/open.c:1236 [inline]
 __se_sys_open fs/open.c:1232 [inline]
 __x64_sys_open+0x221/0x270 fs/open.c:1232
 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: 0033:0x7fe24bee8840
Code: 73 01 c3 48 8b 0d 68 77 20 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d 89 bb 20 00 00 75 10 b8 02 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 1e f6 ff ff 48 89 04 24
RSP: 002b:00007ffe584909b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007ffe58490cc0 RCX: 00007fe24bee8840
RDX: 00000000000001a0 RSI: 0000000000080042 RDI: 0000559848078f40
RBP: 000000000000000d R08: 000000000000ffc0 R09: 00000000ffffffff
R10: 0000000000000069 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000055984806d040 R14: 00007ffe58490c80 R15: 000055984807a420
 </TASK>
----------------
Code disassembly (best guess):
   0:	f5                   	cmc
   1:	48 85 f6             	test   %rsi,%rsi
   4:	74 07                	je     0xd
   6:	48 85 ff             	test   %rdi,%rdi
   9:	75 10                	jne    0x1b
   b:	eb 4e                	jmp    0x5b
   d:	65 48 8b 2c 25 c0 6f 	mov    %gs:0x26fc0,%rbp
  14:	02 00
  16:	48 85 ff             	test   %rdi,%rdi
  19:	74 40                	je     0x5b
  1b:	48 89 ee             	mov    %rbp,%rsi
  1e:	48 89 da             	mov    %rbx,%rdx
  21:	e8 38 e1 e2 08       	callq  0x8e2e15e
  26:	84 c0                	test   %al,%al
  28:	74 31                	je     0x5b
* 2a:	45 31 ff             	xor    %r15d,%r15d <-- trapping instruction
  2d:	4d 85 f6             	test   %r14,%r14
  30:	74 35                	je     0x67
  32:	4d 8b 2e             	mov    (%r14),%r13
  35:	44 8b 23             	mov    (%rbx),%r12d
  38:	49 83 fc 40          	cmp    $0x40,%r12
  3c:	73 50                	jae    0x8e
  3e:	4d                   	rex.WRB
  3f:	0f                   	.byte 0xf

Crashes (3):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-smack-root 2021/11/20 22:10 upstream a90af8f15bdc 4eb20a4e .config log report info INFO: task hung in lo_ioctl
ci-upstream-kasan-gce-386 2021/11/18 00:55 upstream ee1703cda8dc cafff8b6 .config log report info INFO: task hung in lo_ioctl
ci-upstream-kasan-gce-386 2021/11/15 15:21 upstream 8ab774587903 83f5c9b5 .config log report info INFO: task hung in lo_ioctl
* Struck through repros no longer work on HEAD.