============================================ WARNING: possible recursive locking detected 6.15.0-rc1-syzkaller-00173-g0c7cae12f67c #0 Not tainted -------------------------------------------- syz.0.0/5328 is trying to acquire lock: ffff8880554fa740 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline] ffff8880554fa740 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: bch2_symlink+0x178/0x320 fs/bcachefs/fs.c:858 but task is already holding lock: ffff8880554f9078 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline] ffff8880554f9078 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: ovl_copy_up_workdir fs/overlayfs/copy_up.c:782 [inline] ffff8880554f9078 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: ovl_do_copy_up fs/overlayfs/copy_up.c:1001 [inline] ffff8880554f9078 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: ovl_copy_up_one fs/overlayfs/copy_up.c:1202 [inline] ffff8880554f9078 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: ovl_copy_up_flags+0x19d7/0x47f0 fs/overlayfs/copy_up.c:1257 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&sb->s_type->i_mutex_key#20); lock(&sb->s_type->i_mutex_key#20); *** DEADLOCK *** May be due to missing lock nesting notation 6 locks held by syz.0.0/5328: #0: ffff888011c7e420 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:556 #1: ffff8880554f1e50 (&ovl_i_mutex_dir_key[depth]/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:902 [inline] #1: ffff8880554f1e50 (&ovl_i_mutex_dir_key[depth]/1){+.+.}-{4:4}, at: do_unlinkat+0x26c/0x7b0 fs/namei.c:4595 #2: ffff8880554f29e0 (&ovl_i_mutex_key[depth]){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline] #2: ffff8880554f29e0 (&ovl_i_mutex_key[depth]){+.+.}-{4:4}, at: vfs_unlink+0xe4/0x650 fs/namei.c:4533 #3: ffff8880554f2d98 (&ovl_i_lock_key[depth]){+.+.}-{4:4}, at: ovl_inode_lock_interruptible fs/overlayfs/overlayfs.h:651 [inline] #3: ffff8880554f2d98 (&ovl_i_lock_key[depth]){+.+.}-{4:4}, at: ovl_copy_up_start+0x53/0x310 fs/overlayfs/util.c:727 #4: ffff888052b42420 (sb_writers#12){.+.+}-{0:0}, at: ovl_copy_up_workdir fs/overlayfs/copy_up.c:781 [inline] #4: ffff888052b42420 (sb_writers#12){.+.+}-{0:0}, at: ovl_do_copy_up fs/overlayfs/copy_up.c:1001 [inline] #4: ffff888052b42420 (sb_writers#12){.+.+}-{0:0}, at: ovl_copy_up_one fs/overlayfs/copy_up.c:1202 [inline] #4: ffff888052b42420 (sb_writers#12){.+.+}-{0:0}, at: ovl_copy_up_flags+0x19c0/0x47f0 fs/overlayfs/copy_up.c:1257 #5: ffff8880554f9078 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline] #5: ffff8880554f9078 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: ovl_copy_up_workdir fs/overlayfs/copy_up.c:782 [inline] #5: ffff8880554f9078 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: ovl_do_copy_up fs/overlayfs/copy_up.c:1001 [inline] #5: ffff8880554f9078 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: ovl_copy_up_one fs/overlayfs/copy_up.c:1202 [inline] #5: ffff8880554f9078 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: ovl_copy_up_flags+0x19d7/0x47f0 fs/overlayfs/copy_up.c:1257 stack backtrace: CPU: 0 UID: 0 PID: 5328 Comm: syz.0.0 Not tainted 6.15.0-rc1-syzkaller-00173-g0c7cae12f67c #0 PREEMPT(full) 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+0x241/0x360 lib/dump_stack.c:120 print_deadlock_bug+0x2be/0x2d0 kernel/locking/lockdep.c:3042 check_deadlock kernel/locking/lockdep.c:3094 [inline] validate_chain+0x928/0x24e0 kernel/locking/lockdep.c:3896 __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235 lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866 down_write+0x9c/0x220 kernel/locking/rwsem.c:1577 inode_lock include/linux/fs.h:867 [inline] bch2_symlink+0x178/0x320 fs/bcachefs/fs.c:858 vfs_symlink+0x137/0x2e0 fs/namei.c:4688 ovl_do_symlink+0x85/0xd0 fs/overlayfs/overlayfs.h:268 ovl_create_real+0x271/0x460 fs/overlayfs/dir.c:176 ovl_copy_up_workdir fs/overlayfs/copy_up.c:783 [inline] ovl_do_copy_up fs/overlayfs/copy_up.c:1001 [inline] ovl_copy_up_one fs/overlayfs/copy_up.c:1202 [inline] ovl_copy_up_flags+0x1a0a/0x47f0 fs/overlayfs/copy_up.c:1257 ovl_nlink_start+0x9c/0x410 fs/overlayfs/util.c:1165 ovl_do_remove+0x242/0xda0 fs/overlayfs/dir.c:892 vfs_unlink+0x365/0x650 fs/namei.c:4544 do_unlinkat+0x442/0x7b0 fs/namei.c:4608 __do_sys_unlinkat fs/namei.c:4649 [inline] __se_sys_unlinkat fs/namei.c:4642 [inline] __x64_sys_unlinkat+0xcc/0xf0 fs/namei.c:4642 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff0a498d169 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:00007ff0a0df5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000107 RAX: ffffffffffffffda RBX: 00007ff0a4ba6080 RCX: 00007ff0a498d169 RDX: 0000000000000000 RSI: 0000200000000c40 RDI: ffffffffffffff9c RBP: 00007ff0a4a0e990 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007ff0a4ba6080 R15: 00007ffe2a2f8318