Re: [syzbot] [exfat?] INFO: task hung in do_new_mount (2)
From: Chao Yu
Date: Tue Jun 04 2024 - 10:57:59 EST
#syz set subsystems: fs
On 2024/3/21 22:06, syzbot wrote:
Hello,
syzbot found the following issue on:
HEAD commit: fe46a7dd189e Merge tag 'sound-6.9-rc1' of git://git.kernel..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=156b7946180000
kernel config: https://syzkaller.appspot.com/x/.config?x=4d90a36f0cab495a
dashboard link: https://syzkaller.appspot.com/bug?extid=f59c2feaf7cb5988e877
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1075d2c9180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=161012a5180000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f6c04726a2ae/disk-fe46a7dd.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/09c26ce901ea/vmlinux-fe46a7dd.xz
kernel image: https://storage.googleapis.com/syzbot-assets/134acf7f5322/bzImage-fe46a7dd.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/8eeb4ed4feec/mount_2.gz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f59c2feaf7cb5988e877@xxxxxxxxxxxxxxxxxxxxxxxxx
INFO: task syz-executor238:5068 blocked for more than 143 seconds.
Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor238 state:D stack:25616 pid:5068 tgid:5068 ppid:5063 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5409 [inline]
__schedule+0x1781/0x49d0 kernel/sched/core.c:6736
__schedule_loop kernel/sched/core.c:6813 [inline]
schedule+0x14b/0x320 kernel/sched/core.c:6828
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6885
rwsem_down_write_slowpath+0xeeb/0x13b0 kernel/locking/rwsem.c:1178
__down_write_common+0x1af/0x200 kernel/locking/rwsem.c:1306
inode_lock include/linux/fs.h:793 [inline]
do_lock_mount+0x112/0x3a0 fs/namespace.c:2460
lock_mount fs/namespace.c:2502 [inline]
do_new_mount_fc fs/namespace.c:3289 [inline]
do_new_mount+0x43d/0xb40 fs/namespace.c:3354
do_mount fs/namespace.c:3692 [inline]
__do_sys_mount fs/namespace.c:3898 [inline]
__se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3875
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7f180bc1f26a
RSP: 002b:00007ffce5f8f508 EFLAGS: 00000286 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffce5f8f520 RCX: 00007f180bc1f26a
RDX: 0000000020001500 RSI: 0000000020000140 RDI: 00007ffce5f8f520
RBP: 0000000000000005 R08: 00007ffce5f8f560 R09: 00000000000014f8
R10: 0000000000000800 R11: 0000000000000286 R12: 0000000000000800
R13: 00007ffce5f8f560 R14: 0000000000000004 R15: 0000000000020000
</TASK>
INFO: task syz-executor238:5071 blocked for more than 143 seconds.
Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor238 state:D stack:25336 pid:5071 tgid:5071 ppid:5066 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5409 [inline]
__schedule+0x1781/0x49d0 kernel/sched/core.c:6736
__schedule_loop kernel/sched/core.c:6813 [inline]
schedule+0x14b/0x320 kernel/sched/core.c:6828
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6885
rwsem_down_write_slowpath+0xeeb/0x13b0 kernel/locking/rwsem.c:1178
__down_write_common+0x1af/0x200 kernel/locking/rwsem.c:1306
inode_lock include/linux/fs.h:793 [inline]
do_lock_mount+0x112/0x3a0 fs/namespace.c:2460
lock_mount fs/namespace.c:2502 [inline]
do_new_mount_fc fs/namespace.c:3289 [inline]
do_new_mount+0x43d/0xb40 fs/namespace.c:3354
do_mount fs/namespace.c:3692 [inline]
__do_sys_mount fs/namespace.c:3898 [inline]
__se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3875
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7f180bc1f26a
RSP: 002b:00007ffce5f8f508 EFLAGS: 00000286 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffce5f8f520 RCX: 00007f180bc1f26a
RDX: 0000000020001500 RSI: 0000000020000140 RDI: 00007ffce5f8f520
RBP: 0000000000000005 R08: 00007ffce5f8f560 R09: 00000000000014f8
R10: 0000000000000800 R11: 0000000000000286 R12: 0000000000000800
R13: 00007ffce5f8f560 R14: 0000000000000004 R15: 0000000000020000
</TASK>
INFO: task syz-executor238:5073 blocked for more than 143 seconds.
Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor238 state:D stack:25456 pid:5073 tgid:5073 ppid:5069 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5409 [inline]
__schedule+0x1781/0x49d0 kernel/sched/core.c:6736
__schedule_loop kernel/sched/core.c:6813 [inline]
schedule+0x14b/0x320 kernel/sched/core.c:6828
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6885
rwsem_down_write_slowpath+0xeeb/0x13b0 kernel/locking/rwsem.c:1178
__down_write_common+0x1af/0x200 kernel/locking/rwsem.c:1306
inode_lock include/linux/fs.h:793 [inline]
do_lock_mount+0x112/0x3a0 fs/namespace.c:2460
lock_mount fs/namespace.c:2502 [inline]
do_new_mount_fc fs/namespace.c:3289 [inline]
do_new_mount+0x43d/0xb40 fs/namespace.c:3354
do_mount fs/namespace.c:3692 [inline]
__do_sys_mount fs/namespace.c:3898 [inline]
__se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3875
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7f180bc1f26a
RSP: 002b:00007ffce5f8f508 EFLAGS: 00000286 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffce5f8f520 RCX: 00007f180bc1f26a
RDX: 0000000020001500 RSI: 0000000020000140 RDI: 00007ffce5f8f520
RBP: 0000000000000005 R08: 00007ffce5f8f560 R09: 00000000000014f8
R10: 0000000000000800 R11: 0000000000000286 R12: 0000000000000800
R13: 00007ffce5f8f560 R14: 0000000000000004 R15: 0000000000020000
</TASK>
Showing all locks held in the system:
1 lock held by khungtaskd/29:
#0: ffffffff8e132020 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline]
#0: ffffffff8e132020 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline]
#0: ffffffff8e132020 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6614
2 locks held by getty/4822:
#0: ffff88802a7690a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900031332f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6b5/0x1e10 drivers/tty/n_tty.c:2201
1 lock held by syz-executor238/5068:
#0: ffff88807b2a02b8 (&sb->s_type->i_mutex_key#14){++++}-{3:3}, at: inode_lock include/linux/fs.h:793 [inline]
#0: ffff88807b2a02b8 (&sb->s_type->i_mutex_key#14){++++}-{3:3}, at: do_lock_mount+0x112/0x3a0 fs/namespace.c:2460
3 locks held by syz-executor238/5072:
1 lock held by syz-executor238/5071:
#0: ffff88807b2a02b8 (&sb->s_type->i_mutex_key#14){++++}-{3:3}, at: inode_lock include/linux/fs.h:793 [inline]
#0: ffff88807b2a02b8 (&sb->s_type->i_mutex_key#14){++++}-{3:3}, at: do_lock_mount+0x112/0x3a0 fs/namespace.c:2460
1 lock held by syz-executor238/5073:
#0: ffff88807b2a02b8 (&sb->s_type->i_mutex_key#14){++++}-{3:3}, at: inode_lock include/linux/fs.h:793 [inline]
#0: ffff88807b2a02b8 (&sb->s_type->i_mutex_key#14){++++}-{3:3}, at: do_lock_mount+0x112/0x3a0 fs/namespace.c:2460
2 locks held by syz-executor238/5141:
#0: ffff88801ff6efc8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x259/0x320 fs/file.c:1191
#1: ffff88807b2a02b8 (&sb->s_type->i_mutex_key#14){++++}-{3:3}, at: iterate_dir+0x436/0x6f0 fs/readdir.c:103
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 29 Comm: khungtaskd Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
watchdog+0xfb0/0xff0 kernel/hung_task.c:379
kthread+0x2f0/0x390 kernel/kthread.c:388
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 5072 Comm: syz-executor238 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
RIP: 0010:__sanitizer_cov_trace_cmp8+0x7d/0x90 kernel/kcov.c:285
Code: c1 e1 05 48 8d 41 28 4c 39 c8 77 1e 49 ff c2 4c 89 12 48 c7 44 11 08 06 00 00 00 48 89 7c 11 10 48 89 74 11 18 4c 89 44 11 20 <c3> cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 90 90
RSP: 0018:ffffc90004277398 EFLAGS: 00000093
RAX: 0000000000000000 RBX: 00000000000000a0 RCX: ffff888011465a00
RDX: ffff888011465a00 RSI: 00000000000000a0 RDI: 0000000000000080
RBP: ffffc900042774e0 R08: ffffffff8217736e R09: 1ffffffff289d8e4
R10: dffffc0000000000 R11: fffffbfff289d8e5 R12: ffff88807b1262b8
R13: 0000000000039030 R14: 0000000000000000 R15: 0000000000000080
FS: 00005555679ce380(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f180361f000 CR3: 000000007721e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<TASK>
lookup_bh_lru fs/buffer.c:1370 [inline]
__find_get_block+0x46e/0x10d0 fs/buffer.c:1397
bdev_getblk+0x38/0x610 fs/buffer.c:1423
__bread_gfp+0xac/0x430 fs/buffer.c:1474
sb_bread include/linux/buffer_head.h:321 [inline]
exfat_get_dentry+0x53b/0x730 fs/exfat/dir.c:770
exfat_readdir fs/exfat/dir.c:121 [inline]
exfat_iterate+0xbd7/0x33e0 fs/exfat/dir.c:261
wrap_directory_iterator+0x94/0xe0 fs/readdir.c:67
iterate_dir+0x539/0x6f0 fs/readdir.c:110
__do_sys_getdents64 fs/readdir.c:409 [inline]
__se_sys_getdents64+0x20d/0x4f0 fs/readdir.c:394
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7f180bc1ded9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 17 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffce5f8f698 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007f180bc67082 RCX: 00007f180bc1ded9
RDX: 0000000000000646 RSI: 0000000020000240 RDI: 0000000000000005
RBP: 0030656c69662f2e R08: 00005555679cf378 R09: 00005555679cf378
R10: 00000000000014f8 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffce5f8f6d0 R14: 00007ffce5f8f6bc R15: 00007f180bc6703b
</TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.453 msecs
---
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