[syzbot] [kernfs?] possible deadlock in kernfs_fop_write_iter
2 views
Skip to first unread message
syzbot
Jul 1, 2024, 6:38:27 PM (17 hours ago) Jul 1
to gre...@linuxfoundation.org, linux-...@vger.kernel.org, syzkall...@googlegroups.com, t...@kernel.org
Hello,
syzbot found the following issue on:
HEAD commit: 66e55ff12e73 Merge tag 'for-6.10-rc5-tag' of git://git.ker..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15f114c6980000
kernel config: https://syzkaller.appspot.com/x/.config?x=7bd7d605618e43de
dashboard link: https://syzkaller.appspot.com/bug?extid=24386307cce6239b5f68
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-66e55ff1.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/48d9401391cb/vmlinux-66e55ff1.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8e93c493254b/bzImage-66e55ff1.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+243863...@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
6.10.0-rc5-syzkaller-00155-g66e55ff12e73 #0 Not tainted
------------------------------------------------------
syz.2.1818/11922 is trying to acquire lock:
ffff88803d074c88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x281/0x500 fs/kernfs/file.c:325
but task is already holding lock:
ffff88802d7a3868 (&pipe->mutex){+.+.}-{3:3}, at: pipe_lock fs/pipe.c:92 [inline]
ffff88802d7a3868 (&pipe->mutex){+.+.}-{3:3}, at: pipe_lock+0x64/0x80 fs/pipe.c:89
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (&pipe->mutex){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
pipe_lock fs/pipe.c:92 [inline]
pipe_lock+0x64/0x80 fs/pipe.c:89
iter_file_splice_write+0x1f0/0x10b0 fs/splice.c:687
do_splice_from fs/splice.c:941 [inline]
do_splice+0x148c/0x1f90 fs/splice.c:1354
__do_splice+0x327/0x360 fs/splice.c:1436
__do_sys_splice fs/splice.c:1652 [inline]
__se_sys_splice fs/splice.c:1634 [inline]
__x64_sys_splice+0x1d2/0x260 fs/splice.c:1634
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #2 (sb_writers#5){.+.+}-{0:0}:
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1655 [inline]
sb_start_write include/linux/fs.h:1791 [inline]
mnt_want_write+0x6f/0x450 fs/namespace.c:409
ovl_set_or_remove_acl fs/overlayfs/inode.c:517 [inline]
ovl_set_acl+0x518/0xa00 fs/overlayfs/inode.c:566
set_posix_acl+0x25c/0x320 fs/posix_acl.c:955
vfs_set_acl+0x53d/0x940 fs/posix_acl.c:1134
do_set_acl+0x15a/0x1b0 fs/posix_acl.c:1279
do_setxattr+0xeb/0x170 fs/xattr.c:626
setxattr+0x15d/0x180 fs/xattr.c:652
path_setxattr+0x179/0x1e0 fs/xattr.c:671
__do_sys_lsetxattr fs/xattr.c:694 [inline]
__se_sys_lsetxattr fs/xattr.c:690 [inline]
__x64_sys_lsetxattr+0xc1/0x160 fs/xattr.c:690
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (&ovl_i_mutex_dir_key[depth]#2){++++}-{3:3}:
down_read+0x9a/0x330 kernel/locking/rwsem.c:1526
inode_lock_shared include/linux/fs.h:801 [inline]
lookup_slow fs/namei.c:1708 [inline]
walk_component+0x342/0x5b0 fs/namei.c:2004
lookup_last fs/namei.c:2469 [inline]
path_lookupat+0x17f/0x770 fs/namei.c:2493
filename_lookup+0x1e5/0x5b0 fs/namei.c:2522
kern_path+0x35/0x50 fs/namei.c:2630
lookup_bdev+0xd9/0x280 block/bdev.c:1157
resume_store+0x1d8/0x460 kernel/power/hibernate.c:1235
kobj_attr_store+0x55/0x80 lib/kobject.c:840
sysfs_kf_write+0x117/0x170 fs/sysfs/file.c:136
kernfs_fop_write_iter+0x343/0x500 fs/kernfs/file.c:334
new_sync_write fs/read_write.c:497 [inline]
vfs_write+0x6b6/0x1140 fs/read_write.c:590
ksys_write+0x12f/0x260 fs/read_write.c:643
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&of->mutex){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain kernel/locking/lockdep.c:3869 [inline]
__lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
kernfs_fop_write_iter+0x281/0x500 fs/kernfs/file.c:325
iter_file_splice_write+0x906/0x10b0 fs/splice.c:743
do_splice_from fs/splice.c:941 [inline]
do_splice+0x148c/0x1f90 fs/splice.c:1354
__do_splice+0x327/0x360 fs/splice.c:1436
__do_sys_splice fs/splice.c:1652 [inline]
__se_sys_splice fs/splice.c:1634 [inline]
__x64_sys_splice+0x1d2/0x260 fs/splice.c:1634
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Chain exists of:
&of->mutex --> sb_writers#5 --> &pipe->mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&pipe->mutex);
lock(sb_writers#5);
lock(&pipe->mutex);
lock(&of->mutex);
*** DEADLOCK ***
2 locks held by syz.2.1818/11922:
#0: ffff888024784420 (sb_writers#9){.+.+}-{0:0}, at: __do_splice+0x327/0x360 fs/splice.c:1436
#1: ffff88802d7a3868 (&pipe->mutex){+.+.}-{3:3}, at: pipe_lock fs/pipe.c:92 [inline]
#1: ffff88802d7a3868 (&pipe->mutex){+.+.}-{3:3}, at: pipe_lock+0x64/0x80 fs/pipe.c:89
stack backtrace:
CPU: 2 PID: 11922 Comm: syz.2.1818 Not tainted 6.10.0-rc5-syzkaller-00155-g66e55ff12e73 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2187
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain kernel/locking/lockdep.c:3869 [inline]
__lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
kernfs_fop_write_iter+0x281/0x500 fs/kernfs/file.c:325
iter_file_splice_write+0x906/0x10b0 fs/splice.c:743
do_splice_from fs/splice.c:941 [inline]
do_splice+0x148c/0x1f90 fs/splice.c:1354
__do_splice+0x327/0x360 fs/splice.c:1436
__do_sys_splice fs/splice.c:1652 [inline]
__se_sys_splice fs/splice.c:1634 [inline]
__x64_sys_splice+0x1d2/0x260 fs/splice.c:1634
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5821175b29
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5821e78048 EFLAGS: 00000246 ORIG_RAX: 0000000000000113
RAX: ffffffffffffffda RBX: 00007f5821304070 RCX: 00007f5821175b29
RDX: 0000000000000006 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f58211f6756 R08: 000000000000bfd1 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007f5821304070 R15: 00007ffda6f8dbe8
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
syzbot found the following issue on:
HEAD commit: 66e55ff12e73 Merge tag 'for-6.10-rc5-tag' of git://git.ker..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15f114c6980000
kernel config: https://syzkaller.appspot.com/x/.config?x=7bd7d605618e43de
dashboard link: https://syzkaller.appspot.com/bug?extid=24386307cce6239b5f68
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-66e55ff1.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/48d9401391cb/vmlinux-66e55ff1.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8e93c493254b/bzImage-66e55ff1.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+243863...@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
6.10.0-rc5-syzkaller-00155-g66e55ff12e73 #0 Not tainted
------------------------------------------------------
syz.2.1818/11922 is trying to acquire lock:
ffff88803d074c88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x281/0x500 fs/kernfs/file.c:325
but task is already holding lock:
ffff88802d7a3868 (&pipe->mutex){+.+.}-{3:3}, at: pipe_lock fs/pipe.c:92 [inline]
ffff88802d7a3868 (&pipe->mutex){+.+.}-{3:3}, at: pipe_lock+0x64/0x80 fs/pipe.c:89
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (&pipe->mutex){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
pipe_lock fs/pipe.c:92 [inline]
pipe_lock+0x64/0x80 fs/pipe.c:89
iter_file_splice_write+0x1f0/0x10b0 fs/splice.c:687
do_splice_from fs/splice.c:941 [inline]
do_splice+0x148c/0x1f90 fs/splice.c:1354
__do_splice+0x327/0x360 fs/splice.c:1436
__do_sys_splice fs/splice.c:1652 [inline]
__se_sys_splice fs/splice.c:1634 [inline]
__x64_sys_splice+0x1d2/0x260 fs/splice.c:1634
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #2 (sb_writers#5){.+.+}-{0:0}:
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1655 [inline]
sb_start_write include/linux/fs.h:1791 [inline]
mnt_want_write+0x6f/0x450 fs/namespace.c:409
ovl_set_or_remove_acl fs/overlayfs/inode.c:517 [inline]
ovl_set_acl+0x518/0xa00 fs/overlayfs/inode.c:566
set_posix_acl+0x25c/0x320 fs/posix_acl.c:955
vfs_set_acl+0x53d/0x940 fs/posix_acl.c:1134
do_set_acl+0x15a/0x1b0 fs/posix_acl.c:1279
do_setxattr+0xeb/0x170 fs/xattr.c:626
setxattr+0x15d/0x180 fs/xattr.c:652
path_setxattr+0x179/0x1e0 fs/xattr.c:671
__do_sys_lsetxattr fs/xattr.c:694 [inline]
__se_sys_lsetxattr fs/xattr.c:690 [inline]
__x64_sys_lsetxattr+0xc1/0x160 fs/xattr.c:690
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (&ovl_i_mutex_dir_key[depth]#2){++++}-{3:3}:
down_read+0x9a/0x330 kernel/locking/rwsem.c:1526
inode_lock_shared include/linux/fs.h:801 [inline]
lookup_slow fs/namei.c:1708 [inline]
walk_component+0x342/0x5b0 fs/namei.c:2004
lookup_last fs/namei.c:2469 [inline]
path_lookupat+0x17f/0x770 fs/namei.c:2493
filename_lookup+0x1e5/0x5b0 fs/namei.c:2522
kern_path+0x35/0x50 fs/namei.c:2630
lookup_bdev+0xd9/0x280 block/bdev.c:1157
resume_store+0x1d8/0x460 kernel/power/hibernate.c:1235
kobj_attr_store+0x55/0x80 lib/kobject.c:840
sysfs_kf_write+0x117/0x170 fs/sysfs/file.c:136
kernfs_fop_write_iter+0x343/0x500 fs/kernfs/file.c:334
new_sync_write fs/read_write.c:497 [inline]
vfs_write+0x6b6/0x1140 fs/read_write.c:590
ksys_write+0x12f/0x260 fs/read_write.c:643
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&of->mutex){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain kernel/locking/lockdep.c:3869 [inline]
__lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
kernfs_fop_write_iter+0x281/0x500 fs/kernfs/file.c:325
iter_file_splice_write+0x906/0x10b0 fs/splice.c:743
do_splice_from fs/splice.c:941 [inline]
do_splice+0x148c/0x1f90 fs/splice.c:1354
__do_splice+0x327/0x360 fs/splice.c:1436
__do_sys_splice fs/splice.c:1652 [inline]
__se_sys_splice fs/splice.c:1634 [inline]
__x64_sys_splice+0x1d2/0x260 fs/splice.c:1634
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Chain exists of:
&of->mutex --> sb_writers#5 --> &pipe->mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&pipe->mutex);
lock(sb_writers#5);
lock(&pipe->mutex);
lock(&of->mutex);
*** DEADLOCK ***
2 locks held by syz.2.1818/11922:
#0: ffff888024784420 (sb_writers#9){.+.+}-{0:0}, at: __do_splice+0x327/0x360 fs/splice.c:1436
#1: ffff88802d7a3868 (&pipe->mutex){+.+.}-{3:3}, at: pipe_lock fs/pipe.c:92 [inline]
#1: ffff88802d7a3868 (&pipe->mutex){+.+.}-{3:3}, at: pipe_lock+0x64/0x80 fs/pipe.c:89
stack backtrace:
CPU: 2 PID: 11922 Comm: syz.2.1818 Not tainted 6.10.0-rc5-syzkaller-00155-g66e55ff12e73 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2187
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain kernel/locking/lockdep.c:3869 [inline]
__lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
kernfs_fop_write_iter+0x281/0x500 fs/kernfs/file.c:325
iter_file_splice_write+0x906/0x10b0 fs/splice.c:743
do_splice_from fs/splice.c:941 [inline]
do_splice+0x148c/0x1f90 fs/splice.c:1354
__do_splice+0x327/0x360 fs/splice.c:1436
__do_sys_splice fs/splice.c:1652 [inline]
__se_sys_splice fs/splice.c:1634 [inline]
__x64_sys_splice+0x1d2/0x260 fs/splice.c:1634
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5821175b29
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5821e78048 EFLAGS: 00000246 ORIG_RAX: 0000000000000113
RAX: ffffffffffffffda RBX: 00007f5821304070 RCX: 00007f5821175b29
RDX: 0000000000000006 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f58211f6756 R08: 000000000000bfd1 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007f5821304070 R15: 00007ffda6f8dbe8
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
Reply all
Reply to author
Forward
0 new messages