syzbot

ext4 filesystem being mounted at /syzkaller-testdir2930784424/syzkaller.sCEaov/122/file0 supports timestamps until 2038 (0x7fffffff)
======================================================
WARNING: possible circular locking dependency detected
6.3.0-rc2-syzkaller-00181-gcb80b960ce44 #0 Not tainted
------------------------------------------------------
syz-executor.1/6457 is trying to acquire lock:
ffff88802884a8e8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline]
ffff88802884a8e8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_xattr_set_handle+0x160/0x1510 fs/ext4/xattr.c:2373

but task is already holding lock:
ffff88802884ac20 (&ea_inode->i_rwsem#8/1){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
ffff88802884ac20 (&ea_inode->i_rwsem#8/1){+.+.}-{3:3}, at: vfs_setxattr+0x120/0x340 fs/xattr.c:323

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&ea_inode->i_rwsem#8/1){+.+.}-{3:3}:
       down_write+0x92/0x200 kernel/locking/rwsem.c:1573
       inode_lock include/linux/fs.h:758 [inline]
       ext4_xattr_inode_create fs/ext4/xattr.c:1525 [inline]
       ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1608 [inline]
       ext4_xattr_set_entry+0x2b19/0x39e0 fs/ext4/xattr.c:1737
       ext4_xattr_block_set+0xcb7/0x3030 fs/ext4/xattr.c:2043
       ext4_xattr_set_handle+0xd8a/0x1510 fs/ext4/xattr.c:2458
       ext4_xattr_set+0x144/0x360 fs/ext4/xattr.c:2560
       __vfs_setxattr+0x173/0x1e0 fs/xattr.c:203
       __vfs_setxattr_noperm+0x129/0x5f0 fs/xattr.c:237
       __vfs_setxattr_locked+0x1d3/0x260 fs/xattr.c:298
       vfs_setxattr+0x143/0x340 fs/xattr.c:324
       do_setxattr+0x147/0x190 fs/xattr.c:609
       setxattr+0x146/0x160 fs/xattr.c:632
       path_setxattr+0x197/0x1c0 fs/xattr.c:651
       __do_sys_setxattr fs/xattr.c:667 [inline]
       __se_sys_setxattr fs/xattr.c:663 [inline]
       __ia32_sys_setxattr+0xc0/0x160 fs/xattr.c:663
       do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
       __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178
       do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
       entry_SYSENTER_compat_after_hwframe+0x70/0x82

-> #0 (&ei->xattr_sem){++++}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3098 [inline]
       check_prevs_add kernel/locking/lockdep.c:3217 [inline]
       validate_chain kernel/locking/lockdep.c:3832 [inline]
       __lock_acquire+0x2ec7/0x5d40 kernel/locking/lockdep.c:5056
       lock_acquire kernel/locking/lockdep.c:5669 [inline]
       lock_acquire+0x1af/0x520 kernel/locking/lockdep.c:5634
       down_write+0x92/0x200 kernel/locking/rwsem.c:1573
       ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline]
       ext4_xattr_set_handle+0x160/0x1510 fs/ext4/xattr.c:2373
       ext4_xattr_set+0x144/0x360 fs/ext4/xattr.c:2560
       __vfs_setxattr+0x173/0x1e0 fs/xattr.c:203
       __vfs_setxattr_noperm+0x129/0x5f0 fs/xattr.c:237
       __vfs_setxattr_locked+0x1d3/0x260 fs/xattr.c:298
       vfs_setxattr+0x143/0x340 fs/xattr.c:324
       do_setxattr+0x147/0x190 fs/xattr.c:609
       setxattr+0x146/0x160 fs/xattr.c:632
       path_setxattr+0x197/0x1c0 fs/xattr.c:651
       __do_sys_lsetxattr fs/xattr.c:674 [inline]
       __se_sys_lsetxattr fs/xattr.c:670 [inline]
       __ia32_sys_lsetxattr+0xbd/0x150 fs/xattr.c:670
       do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
       __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178
       do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
       entry_SYSENTER_compat_after_hwframe+0x70/0x82

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ea_inode->i_rwsem#8/1);
                               lock(&ei->xattr_sem);
                               lock(&ea_inode->i_rwsem#8/1);
  lock(&ei->xattr_sem);

 *** DEADLOCK ***

2 locks held by syz-executor.1/6457:
 #0: ffff8880245d6460 (sb_writers#4){.+.+}-{0:0}, at: path_setxattr+0xb2/0x1c0 fs/xattr.c:649
 #1: ffff88802884ac20 (&ea_inode->i_rwsem#8/1){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #1: ffff88802884ac20 (&ea_inode->i_rwsem#8/1){+.+.}-{3:3}, at: vfs_setxattr+0x120/0x340 fs/xattr.c:323

stack backtrace:
CPU: 1 PID: 6457 Comm: syz-executor.1 Not tainted 6.3.0-rc2-syzkaller-00181-gcb80b960ce44 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2178
 check_prev_add kernel/locking/lockdep.c:3098 [inline]
 check_prevs_add kernel/locking/lockdep.c:3217 [inline]
 validate_chain kernel/locking/lockdep.c:3832 [inline]
 __lock_acquire+0x2ec7/0x5d40 kernel/locking/lockdep.c:5056
 lock_acquire kernel/locking/lockdep.c:5669 [inline]
 lock_acquire+0x1af/0x520 kernel/locking/lockdep.c:5634
 down_write+0x92/0x200 kernel/locking/rwsem.c:1573
 ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline]
 ext4_xattr_set_handle+0x160/0x1510 fs/ext4/xattr.c:2373
 ext4_xattr_set+0x144/0x360 fs/ext4/xattr.c:2560
 __vfs_setxattr+0x173/0x1e0 fs/xattr.c:203
 __vfs_setxattr_noperm+0x129/0x5f0 fs/xattr.c:237
 __vfs_setxattr_locked+0x1d3/0x260 fs/xattr.c:298
 vfs_setxattr+0x143/0x340 fs/xattr.c:324
 do_setxattr+0x147/0x190 fs/xattr.c:609
 setxattr+0x146/0x160 fs/xattr.c:632
 path_setxattr+0x197/0x1c0 fs/xattr.c:651
 __do_sys_lsetxattr fs/xattr.c:674 [inline]
 __se_sys_lsetxattr fs/xattr.c:670 [inline]
 __ia32_sys_lsetxattr+0xbd/0x150 fs/xattr.c:670
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
 entry_SYSENTER_compat_after_hwframe+0x70/0x82
RIP: 0023:0xf7fd1579
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:00000000f7fcc5cc EFLAGS: 00000296 ORIG_RAX: 00000000000000e3
RAX: ffffffffffffffda RBX: 0000000020000080 RCX: 0000000020000180
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
----------------
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                   	retq
  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