syzbot


INFO: task hung in iterate_supers (2)

Status: auto-closed as invalid on 2020/10/09 12:15
Reported-by: syzbot+f48cf8e0f81e90f12045@syzkaller.appspotmail.com
First crash: 965d, last: 965d
similar bugs (7):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-414 INFO: task hung in iterate_supers 1 1555d 1393d 0/1 auto-closed as invalid on 2019/04/28 09:45
linux-4.14 INFO: task hung in iterate_supers 16 763d 1378d 0/1 auto-closed as invalid on 2021/04/29 12:11
upstream INFO: task hung in iterate_supers reiserfs vfs exfat ntfs3 gfs2 xfs ntfs C error 740 17m 1667d 0/24 upstream: reported C repro on 2018/07/10 10:30
linux-4.19 INFO: task hung in iterate_supers 7 1098d 1285d 0/1 auto-closed as invalid on 2020/05/29 21:42
linux-4.19 INFO: task hung in iterate_supers (3) vfs reiserfs syz 341 1d13h 773d 0/1 upstream: reported syz repro on 2020/12/20 03:38
android-49 INFO: task hung in iterate_supers 19 1617d 1717d 0/3 auto-closed as invalid on 2019/02/25 14:49
android-414 INFO: task hung in iterate_supers (2) 1 1374d 1374d 0/1 auto-closed as invalid on 2019/10/25 08:49

Sample crash report:
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
INFO: task syz-executor.1:10908 blocked for more than 140 seconds.
      Not tainted 4.19.128-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1  D29904 10908   6584 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2826 [inline]
 __schedule+0x8a2/0x1fc0 kernel/sched/core.c:3515
 schedule+0x8d/0x1b0 kernel/sched/core.c:3559
 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline]
 rwsem_down_read_failed+0x21a/0x3b0 kernel/locking/rwsem-xadd.c:309
 call_rwsem_down_read_failed+0x14/0x30 arch/x86/lib/rwsem.S:94
 __down_read arch/x86/include/asm/rwsem.h:83 [inline]
 down_read+0x45/0xb0 kernel/locking/rwsem.c:26
 iterate_supers+0xdb/0x290 fs/super.c:631
 ksys_sync+0x86/0x150 fs/sync.c:113
 __ia32_sys_sync+0xa/0x10 fs/sync.c:124
 do_syscall_32_irqs_on arch/x86/entry/common.c:329 [inline]
 do_int80_syscall_32+0x140/0x680 arch/x86/entry/common.c:352
 entry_INT80_compat+0x76/0x80 arch/x86/entry/entry_64_compat.S:408

Showing all locks held in the system:
1 lock held by khungtaskd/1076:
 #0: 000000004adf87f6 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4440
1 lock held by in:imklog/6139:
 #0: 000000005f8c3f45 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xe3/0x100 fs/file.c:767
1 lock held by syz-executor.3/10881:
1 lock held by syz-executor.1/10908:
 #0: 000000003df4326d (&type->s_umount_key#65){++++}, at: iterate_supers+0xdb/0x290 fs/super.c:631

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

NMI backtrace for cpu 0
CPU: 0 PID: 1076 Comm: khungtaskd Not tainted 4.19.128-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/0x2fe lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1a6/0x1eb 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+0x962/0xe40 kernel/hung_task.c:287
 kthread+0x30b/0x410 kernel/kthread.c:246
 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: 10881 Comm: syz-executor.3 Not tainted 4.19.128-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__sanitizer_cov_trace_pc+0x47/0x50 kernel/kcov.c:111
Code: 90 d8 12 00 00 83 fa 02 75 20 48 8b 88 e0 12 00 00 8b 80 dc 12 00 00 48 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 65 4c 8b 04 25 40 ee 01 00 65 8b 05 b0
RSP: 0018:ffff88804828f5b8 EFLAGS: 00000246
RAX: 0000000000040000 RBX: 0000000000000001 RCX: ffffc9000c0ed000
RDX: 0000000000040000 RSI: ffffffff8180cce7 RDI: ffff8880a8f9e734
RBP: ffff8880853ca520 R08: ffff8880a8f9e3c0 R09: ffffed1015ce473b
R10: ffffed1015ce473a R11: ffff8880ae7239d3 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: ffffffff88b257d8
FS:  00007f4830b92700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f456c8e7000 CR3: 000000009479e000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 rcu_lock_release include/linux/rcupdate.h:247 [inline]
 rcu_read_unlock include/linux/rcupdate.h:681 [inline]
 find_get_entry+0x507/0x910 mm/filemap.c:1491
 pagecache_get_page+0x48/0xd00 mm/filemap.c:1564
 find_get_page_flags include/linux/pagemap.h:278 [inline]
 __find_get_block_slow fs/buffer.c:206 [inline]
 __find_get_block+0x58b/0xe30 fs/buffer.c:1295
 __getblk_slow fs/buffer.c:1040 [inline]
 __getblk_gfp+0x195/0xa50 fs/buffer.c:1321
 __bread_gfp+0x2a/0x240 fs/buffer.c:1366
 sb_bread include/linux/buffer_head.h:309 [inline]
 udf_tread+0xe8/0x130 fs/udf/misc.c:44
 udf_read_tagged+0x4e/0x530 fs/udf/misc.c:210
 udf_check_anchor_block+0x1b4/0x610 fs/udf/super.c:1809
 udf_scan_anchors+0x488/0x5f0 fs/udf/super.c:1888
 udf_find_anchor fs/udf/super.c:1906 [inline]
 udf_load_vrs+0x618/0xbe0 fs/udf/super.c:1971
 udf_fill_super+0x7c9/0x16a6 fs/udf/super.c:2166
 mount_bdev+0x2fc/0x3b0 fs/super.c:1158
 mount_fs+0xa3/0x30c fs/super.c:1261
 vfs_kern_mount.part.0+0x68/0x400 fs/namespace.c:961
 vfs_kern_mount fs/namespace.c:951 [inline]
 do_new_mount fs/namespace.c:2469 [inline]
 do_mount+0x4f4/0x2b50 fs/namespace.c:2799
 ksys_mount+0xd7/0x150 fs/namespace.c:3015
 __do_sys_mount fs/namespace.c:3029 [inline]
 __se_sys_mount fs/namespace.c:3026 [inline]
 __x64_sys_mount+0xba/0x150 fs/namespace.c:3026
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45ca69
Code: 0d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f4830b91c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000004f6b00 RCX: 000000000045ca69
RDX: 0000000020000180 RSI: 0000000020000080 RDI: 0000000020000440
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000768 R14: 00000000004ca5d3 R15: 00007f4830b926d4

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets Title
ci2-linux-4-19 2020/06/11 12:14 linux-4.19.y 3fc898571b97 3ab7a05a .config console log report
* Struck through repros no longer work on HEAD.