====================================================== WARNING: possible circular locking dependency detected 6.9.0-rc7-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.4/19955 is trying to acquire lock: ffff8880540d5888 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x53/0x3b0 fs/kernfs/file.c:154 but task is already holding lock: ffff888022b93540 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xb7/0xd60 fs/seq_file.c:182 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&p->lock){+.+.}-{3:3}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752 seq_read_iter+0xb7/0xd60 fs/seq_file.c:182 call_read_iter include/linux/fs.h:2104 [inline] copy_splice_read+0x662/0xb60 fs/splice.c:365 do_splice_read fs/splice.c:985 [inline] splice_file_to_pipe+0x299/0x500 fs/splice.c:1295 do_sendfile+0x515/0xdc0 fs/read_write.c:1301 __do_sys_sendfile64 fs/read_write.c:1362 [inline] __se_sys_sendfile64+0x17c/0x1e0 fs/read_write.c:1348 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #3 (&pipe->mutex){+.+.}-{3:3}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752 iter_file_splice_write+0x335/0x14e0 fs/splice.c:687 do_splice_from fs/splice.c:941 [inline] do_splice+0xd77/0x1880 fs/splice.c:1354 __do_splice fs/splice.c:1436 [inline] __do_sys_splice fs/splice.c:1652 [inline] __se_sys_splice+0x331/0x4a0 fs/splice.c:1634 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #2 (sb_writers#35){.+.+}-{0:0}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1664 [inline] sb_start_write+0x4d/0x1c0 include/linux/fs.h:1800 mnt_want_write+0x3f/0x90 fs/namespace.c:409 ovl_setattr+0x2de/0x5a0 fs/overlayfs/inode.c:77 notify_change+0xb9d/0xe70 fs/attr.c:497 chown_common+0x501/0x850 fs/open.c:790 do_fchownat+0x16d/0x250 fs/open.c:821 __do_sys_lchown fs/open.c:846 [inline] __se_sys_lchown fs/open.c:844 [inline] __x64_sys_lchown+0x85/0xa0 fs/open.c:844 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&ovl_i_mutex_dir_key[depth]#3){++++}-{3:3}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 down_read+0xb1/0xa40 kernel/locking/rwsem.c:1526 inode_lock_shared include/linux/fs.h:805 [inline] lookup_slow+0x45/0x70 fs/namei.c:1708 walk_component+0x2e1/0x410 fs/namei.c:2004 lookup_last fs/namei.c:2461 [inline] path_lookupat+0x16f/0x450 fs/namei.c:2485 filename_lookup+0x256/0x610 fs/namei.c:2514 kern_path+0x35/0x50 fs/namei.c:2622 lookup_bdev+0xc5/0x290 block/bdev.c:1136 resume_store+0x1a0/0x710 kernel/power/hibernate.c:1235 kernfs_fop_write_iter+0x3a1/0x500 fs/kernfs/file.c:334 call_write_iter include/linux/fs.h:2110 [inline] new_sync_write fs/read_write.c:497 [inline] vfs_write+0xa84/0xcb0 fs/read_write.c:590 ksys_write+0x1a0/0x2c0 fs/read_write.c:643 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 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+0x18cb/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752 kernfs_seq_start+0x53/0x3b0 fs/kernfs/file.c:154 seq_read_iter+0x3d0/0xd60 fs/seq_file.c:225 call_read_iter include/linux/fs.h:2104 [inline] copy_splice_read+0x662/0xb60 fs/splice.c:365 do_splice_read fs/splice.c:985 [inline] splice_file_to_pipe+0x299/0x500 fs/splice.c:1295 do_sendfile+0x515/0xdc0 fs/read_write.c:1301 __do_sys_sendfile64 fs/read_write.c:1362 [inline] __se_sys_sendfile64+0x17c/0x1e0 fs/read_write.c:1348 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 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 --> &pipe->mutex --> &p->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&p->lock); lock(&pipe->mutex); lock(&p->lock); lock(&of->mutex); *** DEADLOCK *** 2 locks held by syz-executor.4/19955: #0: ffff8880270c1068 (&pipe->mutex){+.+.}-{3:3}, at: splice_file_to_pipe+0x2e/0x500 fs/splice.c:1292 #1: ffff888022b93540 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xb7/0xd60 fs/seq_file.c:182 stack backtrace: CPU: 1 PID: 19955 Comm: syz-executor.4 Not tainted 6.9.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 check_noncircular+0x36a/0x4a0 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+0x18cb/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752 kernfs_seq_start+0x53/0x3b0 fs/kernfs/file.c:154 seq_read_iter+0x3d0/0xd60 fs/seq_file.c:225 call_read_iter include/linux/fs.h:2104 [inline] copy_splice_read+0x662/0xb60 fs/splice.c:365 do_splice_read fs/splice.c:985 [inline] splice_file_to_pipe+0x299/0x500 fs/splice.c:1295 do_sendfile+0x515/0xdc0 fs/read_write.c:1301 __do_sys_sendfile64 fs/read_write.c:1362 [inline] __se_sys_sendfile64+0x17c/0x1e0 fs/read_write.c:1348 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe47ec7dca9 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:00007fe47f9a70c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007fe47edac050 RCX: 00007fe47ec7dca9 RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000003 RBP: 00007fe47ecc947e R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000006e R14: 00007fe47edac050 R15: 00007fffc3f7f038