syzbot


INFO: task hung in vfat_lookup

Status: auto-obsoleted due to no activity on 2023/01/28 11:59
Reported-by: syzbot+62cbc62f6434a0a03a73@syzkaller.appspotmail.com
First crash: 783d, last: 783d
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in vfat_lookup exfat 38 2141d 2269d 0/28 closed as dup on 2018/09/05 22:07
android-49 INFO: task hung in vfat_lookup 13 2279d 2290d 0/3 auto-closed as invalid on 2019/02/22 16:49

Sample crash report:
ieee802154 phy0 wpan0: encryption failed: -22
ieee802154 phy1 wpan1: encryption failed: -22
Bluetooth: hci4: command 0x0406 tx timeout
ieee802154 phy0 wpan0: encryption failed: -22
ieee802154 phy1 wpan1: encryption failed: -22
INFO: task syz-executor.0:31793 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-executor.0  D24120 31793      1 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_preempt_disabled+0xf/0x20 kernel/sched/core.c:3619
 __mutex_lock_common kernel/locking/mutex.c:1016 [inline]
 __mutex_lock+0x5f0/0x1190 kernel/locking/mutex.c:1078
 vfat_lookup+0xeb/0x610 fs/fat/namei_vfat.c:709
 __lookup_slow+0x246/0x4a0 fs/namei.c:1672
 lookup_slow fs/namei.c:1689 [inline]
 walk_component+0x7ac/0xda0 fs/namei.c:1811
 link_path_walk.part.0+0x901/0x1230 fs/namei.c:2142
 link_path_walk fs/namei.c:2073 [inline]
 path_openat+0x1db/0x2df0 fs/namei.c:3536
 do_filp_open+0x18c/0x3f0 fs/namei.c:3567
 do_sys_open+0x3b3/0x520 fs/open.c:1085
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f2ade7120e8
Code: Bad RIP value.
RSP: 002b:00007ffe883c8c60 EFLAGS: 00000287 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000418 RCX: 00007f2ade7120e8
RDX: 0000000000090800 RSI: 00007f2ade76c69a RDI: 00000000ffffff9c
RBP: 00007ffe883c8d2c R08: 0000000000090800 R09: 00007f2ade76c69a
R10: 0000000000000000 R11: 0000000000000287 R12: 0000000000000000
R13: 0000000000156b69 R14: 0000000000000011 R15: 00007ffe883c8d90

Showing all locks held in the system:
1 lock held by khungtaskd/1570:
 #0: 000000006270fcc6 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441
1 lock held by in:imklog/7856:
 #0: 0000000005e3430f (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767
2 locks held by syz-executor.0/31793:
 #0: 00000000f2dcf3d9 (&sb->s_type->i_mutex_key#26){++++}, at: inode_lock_shared include/linux/fs.h:758 [inline]
 #0: 00000000f2dcf3d9 (&sb->s_type->i_mutex_key#26){++++}, at: lookup_slow fs/namei.c:1688 [inline]
 #0: 00000000f2dcf3d9 (&sb->s_type->i_mutex_key#26){++++}, at: walk_component+0x798/0xda0 fs/namei.c:1811
 #1: 000000005afc7630 (&sbi->s_lock){+.+.}, at: vfat_lookup+0xeb/0x610 fs/fat/namei_vfat.c:709
3 locks held by syz-executor.0/9085:

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

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 09/22/2022
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: 9085 Comm: syz-executor.0 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
RIP: 0010:rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:348 [inline]
RIP: 0010:rcu_is_watching+0xd/0xc0 kernel/rcu/tree.c:1025
Code: 00 00 e8 f6 d7 46 00 e9 f4 f3 ff ff 48 8b 7c 24 18 e8 07 d9 46 00 e9 c8 f3 ff ff 66 90 55 53 48 83 ec 08 65 ff 05 13 53 b0 7e <e8> 2e 94 25 02 48 c7 c3 c0 2a 02 00 48 ba 00 00 00 00 00 fc ff df
RSP: 0018:ffff88805511f1a0 EFLAGS: 00000282
RAX: 0000000000040000 RBX: 0000000000000000 RCX: ffffc9000c83f000
RDX: 0000000000040000 RSI: ffffffff817c4c77 RDI: 0000000000000001
RBP: ffff8880ae2084e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: dffffc0000000000 R14: 0000000000000000 R15: dffffc0000000000
FS:  00007f2add044700(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f49d22c4000 CR3: 00000000b24c8000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 rcu_read_unlock include/linux/rcupdate.h:677 [inline]
 find_get_entry+0x64c/0x8a0 mm/filemap.c:1491
 pagecache_get_page+0x56/0xd50 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+0x591/0xde0 fs/buffer.c:1295
 __getblk_slow+0x14a/0x9e0 fs/buffer.c:1040
 __getblk_gfp fs/buffer.c:1321 [inline]
 __bread_gfp+0x218/0x300 fs/buffer.c:1366
 sb_bread include/linux/buffer_head.h:309 [inline]
 fat__get_entry+0x4f9/0x8e0 fs/fat/dir.c:101
 fat_get_entry fs/fat/dir.c:129 [inline]
 fat_search_long+0x232/0xdc0 fs/fat/dir.c:477
 vfat_find fs/fat/namei_vfat.c:697 [inline]
 vfat_lookup+0x2d4/0x610 fs/fat/namei_vfat.c:711
 __lookup_slow+0x246/0x4a0 fs/namei.c:1672
 lookup_slow fs/namei.c:1689 [inline]
 walk_component+0x7ac/0xda0 fs/namei.c:1811
 link_path_walk.part.0+0x901/0x1230 fs/namei.c:2142
 link_path_walk fs/namei.c:2073 [inline]
 path_parentat+0x51/0x140 fs/namei.c:2367
 filename_parentat+0x198/0x590 fs/namei.c:2389
 filename_create+0x9e/0x490 fs/namei.c:3621
 user_path_create fs/namei.c:3696 [inline]
 do_mkdirat+0xa0/0x2d0 fs/namei.c:3834
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f2ade7125a9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f2add044168 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f2ade834120 RCX: 00007f2ade7125a9
RDX: 00000000000001ff RSI: 0000000020000000 RDI: ffffffffffffff9c
RBP: 00007f2ade76d580 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe883c8a6f R14: 00007f2add044300 R15: 0000000000022000

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2022/09/30 11:59 linux-4.19.y 3f8a27f9e27b 45fd7169 .config console log report info ci2-linux-4-19 INFO: task hung in vfat_lookup
* Struck through repros no longer work on HEAD.