syzbot


INFO: task hung in ext4_fill_super

Status: upstream: reported C repro on 2021/06/15 09:47
Reported-by: syzbot+3a1400144957f88064a9@syzkaller.appspotmail.com
First crash: 1275d, last: 1095d
Fix bisection: failed (error log, bisect log)
  
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in ext4_fill_super ext4 C inconclusive inconclusive 4 882d 1274d 0/28 auto-obsoleted due to no activity on 2022/11/10 16:49
linux-4.14 INFO: task hung in ext4_fill_super C error 3 827d 1220d 0/1 upstream: reported C repro on 2021/08/09 15:53
Fix bisection attempts (4)
Created Duration User Patch Repo Result
2021/11/20 12:16 11m bisect fix linux-4.19.y error job log
2021/09/25 17:58 28m bisect fix linux-4.19.y OK (0) job log log
2021/08/26 17:30 28m bisect fix linux-4.19.y OK (0) job log log
2021/07/27 16:51 38m bisect fix linux-4.19.y OK (0) job log log

Sample crash report:
EXT4-fs (loop3): get root inode failed
EXT4-fs (loop3): mount failed
EXT4-fs error (device loop5): ext4_fill_super:4450: inode #2: comm syz-executor803: iget: root inode unallocated
EXT4-fs (loop5): get root inode failed
EXT4-fs (loop5): mount failed
INFO: task syz-executor803:11670 blocked for more than 140 seconds.
      Not tainted 4.19.211-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor803 D28088 11670   8116 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2828 [inline]
 __schedule+0x887/0x2040 kernel/sched/core.c:3517
 schedule+0x8d/0x1b0 kernel/sched/core.c:3561
 schedule_timeout+0x92d/0xfe0 kernel/time/timer.c:1794
 do_wait_for_common kernel/sched/completion.c:83 [inline]
 __wait_for_common kernel/sched/completion.c:104 [inline]
 wait_for_common+0x29c/0x470 kernel/sched/completion.c:115
 kthread_stop+0x109/0x6b0 kernel/kthread.c:588
 ext4_fill_super+0x791e/0xc850 fs/ext4/super.c:4646
EXT4-fs error (device loop2): ext4_fill_super:4450: inode #2: comm syz-executor803: iget: root inode unallocated
 mount_bdev+0x2fc/0x3b0 fs/super.c:1158
EXT4-fs error (device loop3): ext4_fill_super:4450: inode #2: comm syz-executor803: iget: root inode unallocated
EXT4-fs error (device loop0): ext4_fill_super:4450: inode #2: comm syz-executor803: iget: root inode unallocated
EXT4-fs (loop3): get root inode failed
 mount_fs+0xa3/0x310 fs/super.c:1261
 vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
EXT4-fs error (device loop4): ext4_fill_super:4450: inode #2: comm syz-executor803: iget: root inode unallocated
 vfs_kern_mount fs/namespace.c:951 [inline]
 do_new_mount fs/namespace.c:2492 [inline]
 do_mount+0x115c/0x2f50 fs/namespace.c:2822
EXT4-fs (loop4): get root inode failed
EXT4-fs error (device loop5): ext4_fill_super:4450: inode #2: comm syz-executor803: iget: root inode unallocated
EXT4-fs (loop3): mount failed
EXT4-fs (loop4): mount failed
EXT4-fs (loop2): get root inode failed
 ksys_mount+0xcf/0x130 fs/namespace.c:3038
 __do_sys_mount fs/namespace.c:3052 [inline]
 __se_sys_mount fs/namespace.c:3049 [inline]
 __x64_sys_mount+0xba/0x150 fs/namespace.c:3049
EXT4-fs (loop5): get root inode failed
EXT4-fs (loop0): get root inode failed
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
EXT4-fs (loop2): mount failed
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f66d6fc308a
EXT4-fs (loop0): mount failed
Code: Bad RIP value.
RSP: 002b:00007f66d6f6e078 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
EXT4-fs (loop5): mount failed
RAX: ffffffffffffffda RBX: 00007f66d6f6e0d0 RCX: 00007f66d6fc308a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f66d6f6e090
RBP: 0000000000000007 R08: 00007f66d6f6e0d0 R09: 00007f66d6f6e6bc
R10: 0000000000000000 R11: 0000000000000202 R12: 00007f66d6f6e090
R13: 00000000200002a8 R14: 0000000000000003 R15: 0000000000000004
EXT4-fs error (device loop4): ext4_fill_super:4450: inode #2: comm syz-executor803: iget: root inode unallocated

Showing all locks held in the system:
EXT4-fs (loop4): get root inode failed
1 lock held by khungtaskd/1570:
EXT4-fs (loop4): mount failed
 #0: 00000000eb2f5904 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441
1 lock held by in:imklog/7834:
2 locks held by systemd-udevd/8141:
 #0: 00000000aaed3dea (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x1d0/0x1480 fs/block_dev.c:1478
 #1: 000000008e9b7aa4 (loop_ctl_mutex){+.+.}, at: lo_open+0x19/0xd0 drivers/block/loop.c:1771
2 locks held by systemd-udevd/8150:
2 locks held by systemd-udevd/8163:
 #0: 00000000e9906daf (&bdev->bd_mutex){+.+.}, at: __blkdev_put+0xfc/0x870 fs/block_dev.c:1806
 #1: 000000008e9b7aa4 (loop_ctl_mutex){+.+.}, at: __loop_clr_fd+0x777/0xe50 drivers/block/loop.c:1164
2 locks held by systemd-udevd/8180:
 #0: 000000005a127379 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x1d0/0x1480 fs/block_dev.c:1478
 #1: 000000008e9b7aa4 (loop_ctl_mutex){+.+.}, at: lo_open+0x19/0xd0 drivers/block/loop.c:1771
2 locks held by systemd-udevd/8208:
 #0: 00000000555e355d (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x1d0/0x1480 fs/block_dev.c:1478
 #1: 000000008e9b7aa4 (loop_ctl_mutex){+.+.}, at: lo_open+0x19/0xd0 drivers/block/loop.c:1771
1 lock held by syz-executor803/11670:
 #0: 00000000ac896bd3 (&type->s_umount_key#25/1){+.+.}, at: alloc_super fs/super.c:226 [inline]
 #0: 00000000ac896bd3 (&type->s_umount_key#25/1){+.+.}, at: sget_userns+0x20b/0xcd0 fs/super.c:519
2 locks held by syz-executor803/8763:
 #0: 000000005a127379 (&bdev->bd_mutex){+.+.}, at: __blkdev_put+0xfc/0x870 fs/block_dev.c:1806
 #1: 000000008e9b7aa4 (loop_ctl_mutex){+.+.}, at: lo_release+0x1a/0x1f0 drivers/block/loop.c:1790
2 locks held by syz-executor803/8764:
 #0: 00000000e9906daf (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x1d0/0x1480 fs/block_dev.c:1478
 #1: 000000008e9b7aa4 (loop_ctl_mutex){+.+.}, at: lo_open+0x19/0xd0 drivers/block/loop.c:1771

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

NMI backtrace for cpu 0
CPU: 0 PID: 1570 Comm: khungtaskd Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1a6/0x1f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline]
 watchdog+0x991/0xe60 kernel/hung_task.c:287
 kthread+0x33f/0x460 kernel/kthread.c:259
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4686 Comm: systemd-journal Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:23 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:67 [inline]
RIP: 0010:write_comp_data+0xf/0x70 kernel/kcov.c:122
Code: 8b 11 48 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 c3 0f 1f 84 00 00 00 00 00 49 89 f1 49 89 fa 65 48 8b 34 25 c0 df 01 00 <65> 8b 05 7a 59 9f 7e a9 00 01 1f 00 75 4f 8b 86 60 13 00 00 83 f8
RSP: 0018:ffff8880a1197d80 EFLAGS: 00000246
RAX: 0000000000000001 RBX: 00000000948a4760 RCX: ffffffff812b5c92
RDX: 0000000000000000 RSI: ffff8880a118e400 RDI: 0000000000000007
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000007 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff8b270eb8
FS:  00007f9f16f568c0(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9f14857000 CR3: 00000000a10d8000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __virt_addr_valid+0xa2/0x240 arch/x86/mm/physaddr.c:60
 check_heap_object mm/usercopy.c:232 [inline]
 __check_object_size mm/usercopy.c:290 [inline]
 __check_object_size+0xcb/0x3e0 mm/usercopy.c:260
 check_object_size include/linux/thread_info.h:132 [inline]
 strncpy_from_user+0x9e/0x350 lib/strncpy_from_user.c:117
 getname_flags+0x113/0x590 fs/namei.c:151
 getname fs/namei.c:211 [inline]
 user_path_create fs/namei.c:3696 [inline]
 do_mkdirat+0x8d/0x2d0 fs/namei.c:3834
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f9f16211687
Code: 00 b8 ff ff ff ff c3 0f 1f 40 00 48 8b 05 09 d8 2b 00 64 c7 00 5f 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 b8 53 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d e1 d7 2b 00 f7 d8 64 89 01 48
RSP: 002b:00007ffecff6fc78 EFLAGS: 00000293 ORIG_RAX: 0000000000000053
RAX: ffffffffffffffda RBX: 00007ffecff72b90 RCX: 00007f9f16211687
RDX: 00007f9f16c82a00 RSI: 00000000000001ed RDI: 000055f04f6518a0
RBP: 00007ffecff6fcb0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000069 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000000 R14: 00007ffecff72b90 R15: 00007ffecff701a0
----------------
Code disassembly (best guess):
   0:	8b 11                	mov    (%rcx),%edx
   2:	48 83 c2 01          	add    $0x1,%rdx
   6:	48 39 d0             	cmp    %rdx,%rax
   9:	76 07                	jbe    0x12
   b:	48 89 34 d1          	mov    %rsi,(%rcx,%rdx,8)
   f:	48 89 11             	mov    %rdx,(%rcx)
  12:	c3                   	retq
  13:	0f 1f 84 00 00 00 00 	nopl   0x0(%rax,%rax,1)
  1a:	00
  1b:	49 89 f1             	mov    %rsi,%r9
  1e:	49 89 fa             	mov    %rdi,%r10
  21:	65 48 8b 34 25 c0 df 	mov    %gs:0x1dfc0,%rsi
  28:	01 00
* 2a:	65 8b 05 7a 59 9f 7e 	mov    %gs:0x7e9f597a(%rip),%eax        # 0x7e9f59ab <-- trapping instruction
  31:	a9 00 01 1f 00       	test   $0x1f0100,%eax
  36:	75 4f                	jne    0x87
  38:	8b 86 60 13 00 00    	mov    0x1360(%rsi),%eax
  3e:	83                   	.byte 0x83
  3f:	f8                   	clc

Crashes (9):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2021/10/21 12:16 linux-4.19.y 3f8a27f9e27b f111d03b .config console log report syz C ci2-linux-4-19 INFO: task hung in ext4_fill_super
2021/10/19 17:07 linux-4.19.y 3f8a27f9e27b 24dc29db .config console log report syz C ci2-linux-4-19 INFO: task hung in ext4_fill_super
2021/06/27 16:51 linux-4.19.y eb575cd5d7f6 9d2ab5df .config console log report syz C ci2-linux-4-19 INFO: task hung in ext4_fill_super
2021/06/26 21:48 linux-4.19.y eb575cd5d7f6 9d2ab5df .config console log report syz C ci2-linux-4-19 INFO: task hung in ext4_fill_super
2021/06/25 10:53 linux-4.19.y eb575cd5d7f6 0edbbe31 .config console log report syz C ci2-linux-4-19 INFO: task hung in ext4_fill_super
2021/06/15 16:00 linux-4.19.y 9a2dc0e6c531 8022d7e3 .config console log report syz C ci2-linux-4-19 INFO: task hung in ext4_fill_super
2021/12/12 23:13 linux-4.19.y 3f8a27f9e27b 49ca1f59 .config console log report info ci2-linux-4-19 INFO: task hung in ext4_fill_super
2021/06/26 07:28 linux-4.19.y eb575cd5d7f6 9d2ab5df .config console log report info ci2-linux-4-19 INFO: task hung in ext4_fill_super
2021/06/15 09:46 linux-4.19.y 9a2dc0e6c531 8022d7e3 .config console log report info ci2-linux-4-19 INFO: task hung in ext4_fill_super
* Struck through repros no longer work on HEAD.