====================================================== WARNING: possible circular locking dependency detected 6.13.0-rc7-syzkaller-00102-gce69b4019001 #0 Not tainted ------------------------------------------------------ syz.0.1541/11405 is trying to acquire lock: ffff88805b751c68 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock fs/pipe.c:92 [inline] ffff88805b751c68 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock+0x64/0x80 fs/pipe.c:89 but task is already holding lock: ffff8880686e4420 (sb_writers#5){.+.+}-{0:0}, at: __do_splice+0x327/0x360 fs/splice.c:1436 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (sb_writers#5){.+.+}-{0:0}: percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1725 [inline] sb_start_write include/linux/fs.h:1861 [inline] mnt_want_write+0x6f/0x450 fs/namespace.c:516 ovl_create_object+0x12e/0x300 fs/overlayfs/dir.c:656 lookup_open.isra.0+0x1174/0x14c0 fs/namei.c:3649 open_last_lookups fs/namei.c:3748 [inline] path_openat+0x904/0x2d60 fs/namei.c:3984 do_filp_open+0x20c/0x470 fs/namei.c:4014 do_sys_openat2+0x17a/0x1e0 fs/open.c:1402 do_sys_open fs/open.c:1417 [inline] __do_sys_creat fs/open.c:1495 [inline] __se_sys_creat fs/open.c:1489 [inline] __ia32_sys_creat+0xcc/0x120 fs/open.c:1489 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #3 (&ovl_i_mutex_dir_key[depth]){++++}-{4:4}: down_read+0x9a/0x330 kernel/locking/rwsem.c:1524 inode_lock_shared include/linux/fs.h:828 [inline] lookup_slow fs/namei.c:1807 [inline] walk_component+0x342/0x5b0 fs/namei.c:2112 lookup_last fs/namei.c:2610 [inline] path_lookupat+0x17f/0x770 fs/namei.c:2634 filename_lookup+0x221/0x5f0 fs/namei.c:2663 kern_path+0x35/0x50 fs/namei.c:2771 lookup_bdev+0xd9/0x280 block/bdev.c:1163 resume_store+0x1d8/0x460 kernel/power/hibernate.c:1242 kobj_attr_store+0x55/0x80 lib/kobject.c:840 sysfs_kf_write+0x117/0x170 fs/sysfs/file.c:139 kernfs_fop_write_iter+0x33d/0x500 fs/kernfs/file.c:334 new_sync_write fs/read_write.c:586 [inline] vfs_write+0x5ae/0x1150 fs/read_write.c:679 ksys_write+0x12b/0x250 fs/read_write.c:731 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #2 (&of->mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735 kernfs_seq_start+0x4d/0x240 fs/kernfs/file.c:154 seq_read_iter+0x2ab/0x12b0 fs/seq_file.c:225 kernfs_fop_read_iter+0x414/0x580 fs/kernfs/file.c:279 new_sync_read fs/read_write.c:484 [inline] vfs_read+0x87f/0xbe0 fs/read_write.c:565 ksys_read+0x12b/0x250 fs/read_write.c:708 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #1 (&p->lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735 seq_read_iter+0xd8/0x12b0 fs/seq_file.c:182 proc_reg_read_iter+0x21d/0x310 fs/proc/inode.c:299 copy_splice_read+0x620/0xb90 fs/splice.c:365 do_splice_read fs/splice.c:985 [inline] do_splice_read+0x282/0x370 fs/splice.c:959 splice_file_to_pipe+0x109/0x120 fs/splice.c:1295 do_splice+0x1174/0x1f60 fs/splice.c:1379 __do_splice+0x159/0x360 fs/splice.c:1436 __do_sys_splice fs/splice.c:1639 [inline] __se_sys_splice fs/splice.c:1621 [inline] __ia32_sys_splice+0x189/0x250 fs/splice.c:1621 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #0 (&pipe->mutex){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain kernel/locking/lockdep.c:3904 [inline] __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735 pipe_lock fs/pipe.c:92 [inline] pipe_lock+0x64/0x80 fs/pipe.c:89 iter_file_splice_write+0x1eb/0x10b0 fs/splice.c:687 do_splice_from fs/splice.c:941 [inline] do_splice+0x145c/0x1f60 fs/splice.c:1354 __do_splice+0x327/0x360 fs/splice.c:1436 __do_sys_splice fs/splice.c:1639 [inline] __se_sys_splice fs/splice.c:1621 [inline] __ia32_sys_splice+0x189/0x250 fs/splice.c:1621 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e other info that might help us debug this: Chain exists of: &pipe->mutex --> &ovl_i_mutex_dir_key[depth] --> sb_writers#5 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(sb_writers#5); lock(&ovl_i_mutex_dir_key[depth]); lock(sb_writers#5); lock(&pipe->mutex); *** DEADLOCK *** 1 lock held by syz.0.1541/11405: #0: ffff8880686e4420 (sb_writers#5){.+.+}-{0:0}, at: __do_splice+0x327/0x360 fs/splice.c:1436 stack backtrace: CPU: 0 UID: 0 PID: 11405 Comm: syz.0.1541 Not tainted 6.13.0-rc7-syzkaller-00102-gce69b4019001 #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: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_circular_bug+0x41c/0x610 kernel/locking/lockdep.c:2074 check_noncircular+0x31a/0x400 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 kernel/locking/lockdep.c:3904 [inline] __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735 pipe_lock fs/pipe.c:92 [inline] pipe_lock+0x64/0x80 fs/pipe.c:89 iter_file_splice_write+0x1eb/0x10b0 fs/splice.c:687 do_splice_from fs/splice.c:941 [inline] do_splice+0x145c/0x1f60 fs/splice.c:1354 __do_splice+0x327/0x360 fs/splice.c:1436 __do_sys_splice fs/splice.c:1639 [inline] __se_sys_splice fs/splice.c:1621 [inline] __ia32_sys_splice+0x189/0x250 fs/splice.c:1621 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf70be579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f4c4b55c EFLAGS: 00000296 ORIG_RAX: 0000000000000139 RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000000000 RDX: 0000000000000008 RSI: 0000000000000000 RDI: 0000000000000016 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi