====================================================== WARNING: possible circular locking dependency detected 6.12.0-syzkaller-10296-gaaf20f870da0 #0 Not tainted ------------------------------------------------------ syz.3.3086/20166 is trying to acquire lock: ffff88802f162418 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb4/0xd70 fs/seq_file.c:182 but task is already holding lock: ffff888046f0bc68 (&pipe->mutex){+.+.}-{4:4}, at: splice_file_to_pipe+0x2e/0x500 fs/splice.c:1292 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&pipe->mutex){+.+.}-{4:4}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735 iter_file_splice_write+0x330/0x1510 fs/splice.c:687 do_splice_from fs/splice.c:941 [inline] do_splice+0xd6a/0x18e0 fs/splice.c:1354 __do_splice fs/splice.c:1436 [inline] __do_sys_splice fs/splice.c:1639 [inline] __se_sys_splice+0x2e0/0x450 fs/splice.c:1621 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #3 (sb_writers#5){.+.+}-{0:0}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1725 [inline] sb_start_write+0x4d/0x1c0 include/linux/fs.h:1861 mnt_want_write+0x3f/0x90 fs/namespace.c:515 ovl_create_object+0x13a/0x3a0 fs/overlayfs/dir.c:656 lookup_open fs/namei.c:3649 [inline] open_last_lookups fs/namei.c:3748 [inline] path_openat+0x1c05/0x3590 fs/namei.c:3984 do_filp_open+0x27f/0x4e0 fs/namei.c:4014 do_sys_openat2+0x13e/0x1d0 fs/open.c:1402 do_sys_open fs/open.c:1417 [inline] __do_sys_open fs/open.c:1425 [inline] __se_sys_open fs/open.c:1421 [inline] __x64_sys_open+0x225/0x270 fs/open.c:1421 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #2 (&ovl_i_mutex_dir_key[depth]){++++}-{4:4}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 down_read+0xb1/0xa40 kernel/locking/rwsem.c:1524 inode_lock_shared include/linux/fs.h:828 [inline] lookup_slow+0x45/0x70 fs/namei.c:1807 walk_component+0x2e1/0x410 fs/namei.c:2112 lookup_last fs/namei.c:2610 [inline] path_lookupat+0x16f/0x450 fs/namei.c:2634 filename_lookup+0x2a3/0x670 fs/namei.c:2663 kern_path+0x35/0x50 fs/namei.c:2771 lookup_bdev+0xc5/0x290 block/bdev.c:1164 resume_store+0x1a0/0x710 kernel/power/hibernate.c:1242 kernfs_fop_write_iter+0x3a2/0x500 fs/kernfs/file.c:334 new_sync_write fs/read_write.c:586 [inline] vfs_write+0xaed/0xd30 fs/read_write.c:679 ksys_write+0x18f/0x2b0 fs/read_write.c:731 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&of->mutex){+.+.}-{4:4}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735 kernfs_seq_start+0x53/0x3b0 fs/kernfs/file.c:154 seq_read_iter+0x3ce/0xd70 fs/seq_file.c:225 do_iter_readv_writev+0x602/0x880 vfs_readv+0x2b3/0xa80 fs/read_write.c:1011 do_readv+0x1b6/0x360 fs/read_write.c:1073 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&p->lock){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735 seq_read_iter+0xb4/0xd70 fs/seq_file.c:182 copy_splice_read+0x665/0xb60 fs/splice.c:365 do_splice_read fs/splice.c:985 [inline] splice_file_to_pipe+0x292/0x500 fs/splice.c:1295 do_sendfile+0x508/0x8a0 fs/read_write.c:1369 __do_sys_sendfile64 fs/read_write.c:1424 [inline] __se_sys_sendfile64+0x17c/0x1e0 fs/read_write.c:1410 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: &p->lock --> sb_writers#5 --> &pipe->mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&pipe->mutex); lock(sb_writers#5); lock(&pipe->mutex); lock(&p->lock); *** DEADLOCK *** 1 lock held by syz.3.3086/20166: #0: ffff888046f0bc68 (&pipe->mutex){+.+.}-{4:4}, at: splice_file_to_pipe+0x2e/0x500 fs/splice.c:1292 stack backtrace: CPU: 1 UID: 0 PID: 20166 Comm: syz.3.3086 Not tainted 6.12.0-syzkaller-10296-gaaf20f870da0 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2206 check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735 seq_read_iter+0xb4/0xd70 fs/seq_file.c:182 copy_splice_read+0x665/0xb60 fs/splice.c:365 do_splice_read fs/splice.c:985 [inline] splice_file_to_pipe+0x292/0x500 fs/splice.c:1295 do_sendfile+0x508/0x8a0 fs/read_write.c:1369 __do_sys_sendfile64 fs/read_write.c:1424 [inline] __se_sys_sendfile64+0x17c/0x1e0 fs/read_write.c:1410 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f656ff80809 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:00007f6570e3b058 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f6570145fa0 RCX: 00007f656ff80809 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 000000000000000b RBP: 00007f656fff393e R08: 0000000000000000 R09: 0000000000000000 R10: 0000000080000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f6570145fa0 R15: 00007ffdcd30b238