[v5.15] possible deadlock in seq_read_iter
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syzbot
Apr 28, 2024, 12:21:25 AMApr 28
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: b925f60c6ee7 Linux 5.15.157
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11b80af8980000
kernel config: https://syzkaller.appspot.com/x/.config?x=2a1cb0d51cbb9dfb
dashboard link: https://syzkaller.appspot.com/bug?extid=4b5aa00f98a06734de64
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/07f51426f82f/disk-b925f60c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d41cc73399aa/vmlinux-b925f60c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0f542c09e64b/bzImage-b925f60c.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4b5aa0...@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
5.15.157-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.0/7794 is trying to acquire lock:
ffff88806205dd58 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xae/0xd10 fs/seq_file.c:182
but task is already holding lock:
ffff888063b5a460 (sb_writers#3){.+.+}-{0:0}, at: do_sendfile+0x600/0xff0 fs/read_write.c:1248
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #7 (sb_writers#3){.+.+}-{0:0}:
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1811 [inline]
sb_start_write include/linux/fs.h:1881 [inline]
file_start_write include/linux/fs.h:3037 [inline]
lo_write_bvec+0x1a3/0x740 drivers/block/loop.c:315
lo_write_simple drivers/block/loop.c:338 [inline]
do_req_filebacked drivers/block/loop.c:656 [inline]
loop_handle_cmd drivers/block/loop.c:2234 [inline]
loop_process_work+0x2309/0x2af0 drivers/block/loop.c:2274
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
kthread+0x3f6/0x4f0 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:300
-> #6 ((work_completion)(&worker->work)){+.+.}-{0:0}:
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
process_one_work+0x7f1/0x10c0 kernel/workqueue.c:2286
worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
kthread+0x3f6/0x4f0 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:300
-> #5 ((null)){+.+.}-{0:0}:
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
flush_workqueue+0x170/0x1610 kernel/workqueue.c:2830
drain_workqueue+0xc5/0x390 kernel/workqueue.c:2995
destroy_workqueue+0x7b/0xae0 kernel/workqueue.c:4439
__loop_clr_fd+0x241/0xbe0 drivers/block/loop.c:1383
blkdev_put_whole block/bdev.c:692 [inline]
blkdev_put+0x455/0x790 block/bdev.c:954
deactivate_locked_super+0xa0/0x110 fs/super.c:335
cleanup_mnt+0x44e/0x500 fs/namespace.c:1143
task_work_run+0x129/0x1a0 kernel/task_work.c:164
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop+0x106/0x130 kernel/entry/common.c:181
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307
do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
-> #4 (&lo->lo_mutex){+.+.}-{3:3}:
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
__mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_killable_nested+0x17/0x20 kernel/locking/mutex.c:758
lo_open+0x68/0x100 drivers/block/loop.c:2055
blkdev_get_whole+0x94/0x390 block/bdev.c:669
blkdev_get_by_dev+0x2bc/0xa50 block/bdev.c:824
blkdev_open+0x138/0x2d0 block/fops.c:463
do_dentry_open+0x807/0xfb0 fs/open.c:826
do_open fs/namei.c:3608 [inline]
path_openat+0x2705/0x2f20 fs/namei.c:3742
do_filp_open+0x21c/0x460 fs/namei.c:3769
do_sys_openat2+0x13b/0x500 fs/open.c:1253
do_sys_open fs/open.c:1269 [inline]
__do_sys_openat fs/open.c:1285 [inline]
__se_sys_openat fs/open.c:1280 [inline]
__x64_sys_openat+0x243/0x290 fs/open.c:1280
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
-> #3 (&disk->open_mutex){+.+.}-{3:3}:
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
__mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
blkdev_get_by_dev+0x14d/0xa50 block/bdev.c:817
swsusp_check+0xb1/0x2c0 kernel/power/swap.c:1526
software_resume+0xc6/0x3c0 kernel/power/hibernate.c:977
resume_store+0xe3/0x130 kernel/power/hibernate.c:1179
kernfs_fop_write_iter+0x3a2/0x4f0 fs/kernfs/file.c:296
call_write_iter include/linux/fs.h:2172 [inline]
new_sync_write fs/read_write.c:507 [inline]
vfs_write+0xacf/0xe50 fs/read_write.c:594
ksys_write+0x1a2/0x2c0 fs/read_write.c:647
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
-> #2 (system_transition_mutex/1){+.+.}-{3:3}:
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
__mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
software_resume+0x7c/0x3c0 kernel/power/hibernate.c:932
resume_store+0xe3/0x130 kernel/power/hibernate.c:1179
kernfs_fop_write_iter+0x3a2/0x4f0 fs/kernfs/file.c:296
call_write_iter include/linux/fs.h:2172 [inline]
new_sync_write fs/read_write.c:507 [inline]
vfs_write+0xacf/0xe50 fs/read_write.c:594
ksys_write+0x1a2/0x2c0 fs/read_write.c:647
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
-> #1 (&of->mutex){+.+.}-{3:3}:
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
__mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
kernfs_seq_start+0x50/0x3b0 fs/kernfs/file.c:112
seq_read_iter+0x3d0/0xd10 fs/seq_file.c:225
call_read_iter include/linux/fs.h:2166 [inline]
new_sync_read fs/read_write.c:404 [inline]
vfs_read+0xa9f/0xe10 fs/read_write.c:485
ksys_read+0x1a2/0x2c0 fs/read_write.c:623
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
-> #0 (&p->lock){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
__lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
__mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
seq_read_iter+0xae/0xd10 fs/seq_file.c:182
call_read_iter include/linux/fs.h:2166 [inline]
generic_file_splice_read+0x4ad/0x790 fs/splice.c:311
do_splice_to fs/splice.c:796 [inline]
splice_direct_to_actor+0x448/0xc10 fs/splice.c:870
do_splice_direct+0x285/0x3d0 fs/splice.c:979
do_sendfile+0x625/0xff0 fs/read_write.c:1249
__do_sys_sendfile64 fs/read_write.c:1317 [inline]
__se_sys_sendfile64+0x178/0x1e0 fs/read_write.c:1303
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
other info that might help us debug this:
Chain exists of:
&p->lock --> (work_completion)(&worker->work) --> sb_writers#3
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(sb_writers#3);
lock((work_completion)(&worker->work));
lock(sb_writers#3);
lock(&p->lock);
*** DEADLOCK ***
1 lock held by syz-executor.0/7794:
#0: ffff888063b5a460 (sb_writers#3){.+.+}-{0:0}, at: do_sendfile+0x600/0xff0 fs/read_write.c:1248
stack backtrace:
CPU: 1 PID: 7794 Comm: syz-executor.0 Not tainted 5.15.157-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
check_noncircular+0x2f8/0x3b0 kernel/locking/lockdep.c:2133
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
__lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
__mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
seq_read_iter+0xae/0xd10 fs/seq_file.c:182
call_read_iter include/linux/fs.h:2166 [inline]
generic_file_splice_read+0x4ad/0x790 fs/splice.c:311
do_splice_to fs/splice.c:796 [inline]
splice_direct_to_actor+0x448/0xc10 fs/splice.c:870
do_splice_direct+0x285/0x3d0 fs/splice.c:979
do_sendfile+0x625/0xff0 fs/read_write.c:1249
__do_sys_sendfile64 fs/read_write.c:1317 [inline]
__se_sys_sendfile64+0x178/0x1e0 fs/read_write.c:1303
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f1722781ea9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1720cf40c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f17228aff80 RCX: 00007f1722781ea9
RDX: 0000000000000000 RSI: 0000000000000007 RDI: 0000000000000008
RBP: 00007f17227ce4a4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000080000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f17228aff80 R15: 00007ffd65d7cf08
</TASK>
---
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syzbot found the following issue on:
HEAD commit: b925f60c6ee7 Linux 5.15.157
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11b80af8980000
kernel config: https://syzkaller.appspot.com/x/.config?x=2a1cb0d51cbb9dfb
dashboard link: https://syzkaller.appspot.com/bug?extid=4b5aa00f98a06734de64
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/07f51426f82f/disk-b925f60c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d41cc73399aa/vmlinux-b925f60c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0f542c09e64b/bzImage-b925f60c.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4b5aa0...@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
5.15.157-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.0/7794 is trying to acquire lock:
ffff88806205dd58 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xae/0xd10 fs/seq_file.c:182
but task is already holding lock:
ffff888063b5a460 (sb_writers#3){.+.+}-{0:0}, at: do_sendfile+0x600/0xff0 fs/read_write.c:1248
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #7 (sb_writers#3){.+.+}-{0:0}:
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1811 [inline]
sb_start_write include/linux/fs.h:1881 [inline]
file_start_write include/linux/fs.h:3037 [inline]
lo_write_bvec+0x1a3/0x740 drivers/block/loop.c:315
lo_write_simple drivers/block/loop.c:338 [inline]
do_req_filebacked drivers/block/loop.c:656 [inline]
loop_handle_cmd drivers/block/loop.c:2234 [inline]
loop_process_work+0x2309/0x2af0 drivers/block/loop.c:2274
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
kthread+0x3f6/0x4f0 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:300
-> #6 ((work_completion)(&worker->work)){+.+.}-{0:0}:
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
process_one_work+0x7f1/0x10c0 kernel/workqueue.c:2286
worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
kthread+0x3f6/0x4f0 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:300
-> #5 ((null)){+.+.}-{0:0}:
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
flush_workqueue+0x170/0x1610 kernel/workqueue.c:2830
drain_workqueue+0xc5/0x390 kernel/workqueue.c:2995
destroy_workqueue+0x7b/0xae0 kernel/workqueue.c:4439
__loop_clr_fd+0x241/0xbe0 drivers/block/loop.c:1383
blkdev_put_whole block/bdev.c:692 [inline]
blkdev_put+0x455/0x790 block/bdev.c:954
deactivate_locked_super+0xa0/0x110 fs/super.c:335
cleanup_mnt+0x44e/0x500 fs/namespace.c:1143
task_work_run+0x129/0x1a0 kernel/task_work.c:164
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop+0x106/0x130 kernel/entry/common.c:181
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307
do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
-> #4 (&lo->lo_mutex){+.+.}-{3:3}:
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
__mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_killable_nested+0x17/0x20 kernel/locking/mutex.c:758
lo_open+0x68/0x100 drivers/block/loop.c:2055
blkdev_get_whole+0x94/0x390 block/bdev.c:669
blkdev_get_by_dev+0x2bc/0xa50 block/bdev.c:824
blkdev_open+0x138/0x2d0 block/fops.c:463
do_dentry_open+0x807/0xfb0 fs/open.c:826
do_open fs/namei.c:3608 [inline]
path_openat+0x2705/0x2f20 fs/namei.c:3742
do_filp_open+0x21c/0x460 fs/namei.c:3769
do_sys_openat2+0x13b/0x500 fs/open.c:1253
do_sys_open fs/open.c:1269 [inline]
__do_sys_openat fs/open.c:1285 [inline]
__se_sys_openat fs/open.c:1280 [inline]
__x64_sys_openat+0x243/0x290 fs/open.c:1280
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
-> #3 (&disk->open_mutex){+.+.}-{3:3}:
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
__mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
blkdev_get_by_dev+0x14d/0xa50 block/bdev.c:817
swsusp_check+0xb1/0x2c0 kernel/power/swap.c:1526
software_resume+0xc6/0x3c0 kernel/power/hibernate.c:977
resume_store+0xe3/0x130 kernel/power/hibernate.c:1179
kernfs_fop_write_iter+0x3a2/0x4f0 fs/kernfs/file.c:296
call_write_iter include/linux/fs.h:2172 [inline]
new_sync_write fs/read_write.c:507 [inline]
vfs_write+0xacf/0xe50 fs/read_write.c:594
ksys_write+0x1a2/0x2c0 fs/read_write.c:647
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
-> #2 (system_transition_mutex/1){+.+.}-{3:3}:
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
__mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
software_resume+0x7c/0x3c0 kernel/power/hibernate.c:932
resume_store+0xe3/0x130 kernel/power/hibernate.c:1179
kernfs_fop_write_iter+0x3a2/0x4f0 fs/kernfs/file.c:296
call_write_iter include/linux/fs.h:2172 [inline]
new_sync_write fs/read_write.c:507 [inline]
vfs_write+0xacf/0xe50 fs/read_write.c:594
ksys_write+0x1a2/0x2c0 fs/read_write.c:647
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
-> #1 (&of->mutex){+.+.}-{3:3}:
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
__mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
kernfs_seq_start+0x50/0x3b0 fs/kernfs/file.c:112
seq_read_iter+0x3d0/0xd10 fs/seq_file.c:225
call_read_iter include/linux/fs.h:2166 [inline]
new_sync_read fs/read_write.c:404 [inline]
vfs_read+0xa9f/0xe10 fs/read_write.c:485
ksys_read+0x1a2/0x2c0 fs/read_write.c:623
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
-> #0 (&p->lock){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
__lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
__mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
seq_read_iter+0xae/0xd10 fs/seq_file.c:182
call_read_iter include/linux/fs.h:2166 [inline]
generic_file_splice_read+0x4ad/0x790 fs/splice.c:311
do_splice_to fs/splice.c:796 [inline]
splice_direct_to_actor+0x448/0xc10 fs/splice.c:870
do_splice_direct+0x285/0x3d0 fs/splice.c:979
do_sendfile+0x625/0xff0 fs/read_write.c:1249
__do_sys_sendfile64 fs/read_write.c:1317 [inline]
__se_sys_sendfile64+0x178/0x1e0 fs/read_write.c:1303
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
other info that might help us debug this:
Chain exists of:
&p->lock --> (work_completion)(&worker->work) --> sb_writers#3
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(sb_writers#3);
lock((work_completion)(&worker->work));
lock(sb_writers#3);
lock(&p->lock);
*** DEADLOCK ***
1 lock held by syz-executor.0/7794:
#0: ffff888063b5a460 (sb_writers#3){.+.+}-{0:0}, at: do_sendfile+0x600/0xff0 fs/read_write.c:1248
stack backtrace:
CPU: 1 PID: 7794 Comm: syz-executor.0 Not tainted 5.15.157-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
check_noncircular+0x2f8/0x3b0 kernel/locking/lockdep.c:2133
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
__lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
__mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
seq_read_iter+0xae/0xd10 fs/seq_file.c:182
call_read_iter include/linux/fs.h:2166 [inline]
generic_file_splice_read+0x4ad/0x790 fs/splice.c:311
do_splice_to fs/splice.c:796 [inline]
splice_direct_to_actor+0x448/0xc10 fs/splice.c:870
do_splice_direct+0x285/0x3d0 fs/splice.c:979
do_sendfile+0x625/0xff0 fs/read_write.c:1249
__do_sys_sendfile64 fs/read_write.c:1317 [inline]
__se_sys_sendfile64+0x178/0x1e0 fs/read_write.c:1303
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f1722781ea9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1720cf40c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f17228aff80 RCX: 00007f1722781ea9
RDX: 0000000000000000 RSI: 0000000000000007 RDI: 0000000000000008
RBP: 00007f17227ce4a4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000080000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f17228aff80 R15: 00007ffd65d7cf08
</TASK>
---
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