syzbot

EXT4-fs (loop0): 1 truncate cleaned up
EXT4-fs (loop0): mounted filesystem without journal. Opts: max_batch_time=0x0000000000000004,max_batch_time=0x0000000000000002,debug_want_extra_isize=0x000000000000006a,user_xattr,errors=remount-ro,nombcache,. Quota mode: none.
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.57/4399 is trying to acquire lock:
ffff88805e20d3b0 (&sb->s_type->i_mutex_key#9/1){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
ffff88805e20d3b0 (&sb->s_type->i_mutex_key#9/1){+.+.}-{3:3}, at: ext4_xattr_inode_create fs/ext4/xattr.c:1475 [inline]
ffff88805e20d3b0 (&sb->s_type->i_mutex_key#9/1){+.+.}-{3:3}, at: ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1557 [inline]
ffff88805e20d3b0 (&sb->s_type->i_mutex_key#9/1){+.+.}-{3:3}, at: ext4_xattr_set_entry+0x34fb/0x3d30 fs/ext4/xattr.c:1685

but task is already holding lock:
ffff88805e20dc30 (&ei->i_data_sem/3){++++}-{3:3}, at: ext4_setattr+0x133d/0x19e0 fs/ext4/inode.c:5560

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&ei->i_data_sem/3){++++}-{3:3}:
       down_write+0x38/0x60 kernel/locking/rwsem.c:1551
       ext4_update_i_disksize fs/ext4/ext4.h:3419 [inline]
       ext4_xattr_inode_write fs/ext4/xattr.c:1413 [inline]
       ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1561 [inline]
       ext4_xattr_set_entry+0x32c3/0x3d30 fs/ext4/xattr.c:1685
       ext4_xattr_ibody_set+0x112/0x330 fs/ext4/xattr.c:2253
       ext4_xattr_set_handle+0xa7c/0x12b0 fs/ext4/xattr.c:2410
       ext4_xattr_set+0x22a/0x320 fs/ext4/xattr.c:2523
       __vfs_setxattr+0x3e0/0x420 fs/xattr.c:182
       __vfs_setxattr_noperm+0x129/0x5e0 fs/xattr.c:216
       vfs_setxattr+0x168/0x2f0 fs/xattr.c:303
       do_setxattr fs/xattr.c:588 [inline]
       setxattr+0x2da/0x300 fs/xattr.c:611
       path_setxattr+0x142/0x280 fs/xattr.c:630
       __do_sys_lsetxattr fs/xattr.c:653 [inline]
       __se_sys_lsetxattr fs/xattr.c:649 [inline]
       __x64_sys_lsetxattr+0xb4/0xd0 fs/xattr.c:649
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #0 (&sb->s_type->i_mutex_key#9/1){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain kernel/locking/lockdep.c:3788 [inline]
       __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
       lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
       down_write+0x38/0x60 kernel/locking/rwsem.c:1551
       inode_lock include/linux/fs.h:787 [inline]
       ext4_xattr_inode_create fs/ext4/xattr.c:1475 [inline]
       ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1557 [inline]
       ext4_xattr_set_entry+0x34fb/0x3d30 fs/ext4/xattr.c:1685
       ext4_xattr_block_set+0x973/0x2d30 fs/ext4/xattr.c:2005
       ext4_xattr_move_to_block fs/ext4/xattr.c:2633 [inline]
       ext4_xattr_make_inode_space fs/ext4/xattr.c:2708 [inline]
       ext4_expand_extra_isize_ea+0xf4b/0x19a0 fs/ext4/xattr.c:2800
       __ext4_expand_extra_isize+0x301/0x3e0 fs/ext4/inode.c:5901
       ext4_try_to_expand_extra_isize fs/ext4/inode.c:5944 [inline]
       __ext4_mark_inode_dirty+0x469/0x700 fs/ext4/inode.c:6022
       ext4_setattr+0x13b7/0x19e0 fs/ext4/inode.c:5563
       notify_change+0xbcd/0xee0 fs/attr.c:505
       do_truncate+0x197/0x220 fs/open.c:65
       handle_truncate fs/namei.c:3273 [inline]
       do_open fs/namei.c:3620 [inline]
       path_openat+0x28af/0x2f30 fs/namei.c:3750
       do_filp_open+0x1b3/0x3e0 fs/namei.c:3777
       do_sys_openat2+0x142/0x4a0 fs/open.c:1253
       do_sys_open fs/open.c:1269 [inline]
       __do_sys_openat fs/open.c:1285 [inline]
       __se_sys_openat fs/open.c:1280 [inline]
       __x64_sys_openat+0x135/0x160 fs/open.c:1280
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ei->i_data_sem/3);
                               lock(&sb->s_type->i_mutex_key#9/1);
                               lock(&ei->i_data_sem/3);
  lock(&sb->s_type->i_mutex_key#9/1);

 *** DEADLOCK ***

5 locks held by syz.0.57/4399:
 #0: ffff88807bdaa460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386
 #1: ffff88805e20dda8 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #1: ffff88805e20dda8 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: do_truncate+0x183/0x220 fs/open.c:63
 #2: ffff88805e20df48 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #2: ffff88805e20df48 (mapping.invalidate_lock){++++}-{3:3}, at: ext4_setattr+0xdb6/0x19e0 fs/ext4/inode.c:5520
 #3: ffff88805e20dc30 (&ei->i_data_sem/3){++++}-{3:3}, at: ext4_setattr+0x133d/0x19e0 fs/ext4/inode.c:5560
 #4: ffff88805e20da80 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_trylock_xattr fs/ext4/xattr.h:162 [inline]
 #4: ffff88805e20da80 (&ei->xattr_sem){++++}-{3:3}, at: ext4_try_to_expand_extra_isize fs/ext4/inode.c:5941 [inline]
 #4: ffff88805e20da80 (&ei->xattr_sem){++++}-{3:3}, at: __ext4_mark_inode_dirty+0x3e8/0x700 fs/ext4/inode.c:6022

stack backtrace:
CPU: 1 PID: 4399 Comm: syz.0.57 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain kernel/locking/lockdep.c:3788 [inline]
 __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
 down_write+0x38/0x60 kernel/locking/rwsem.c:1551
 inode_lock include/linux/fs.h:787 [inline]
 ext4_xattr_inode_create fs/ext4/xattr.c:1475 [inline]
 ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1557 [inline]
 ext4_xattr_set_entry+0x34fb/0x3d30 fs/ext4/xattr.c:1685
 ext4_xattr_block_set+0x973/0x2d30 fs/ext4/xattr.c:2005
 ext4_xattr_move_to_block fs/ext4/xattr.c:2633 [inline]
 ext4_xattr_make_inode_space fs/ext4/xattr.c:2708 [inline]
 ext4_expand_extra_isize_ea+0xf4b/0x19a0 fs/ext4/xattr.c:2800
 __ext4_expand_extra_isize+0x301/0x3e0 fs/ext4/inode.c:5901
 ext4_try_to_expand_extra_isize fs/ext4/inode.c:5944 [inline]
 __ext4_mark_inode_dirty+0x469/0x700 fs/ext4/inode.c:6022
 ext4_setattr+0x13b7/0x19e0 fs/ext4/inode.c:5563
 notify_change+0xbcd/0xee0 fs/attr.c:505
 do_truncate+0x197/0x220 fs/open.c:65
 handle_truncate fs/namei.c:3273 [inline]
 do_open fs/namei.c:3620 [inline]
 path_openat+0x28af/0x2f30 fs/namei.c:3750
 do_filp_open+0x1b3/0x3e0 fs/namei.c:3777
 do_sys_openat2+0x142/0x4a0 fs/open.c:1253
 do_sys_open fs/open.c:1269 [inline]
 __do_sys_openat fs/open.c:1285 [inline]
 __se_sys_openat fs/open.c:1280 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1280
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f4fe2a376c9
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:00007fffca6fdab8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f4fe2c8dfa0 RCX: 00007f4fe2a376c9
RDX: 00000000000ce342 RSI: 00002000000002c0 RDI: ffffffffffffff9c
RBP: 00007f4fe2ab9f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4fe2c8dfa0 R14: 00007f4fe2c8dfa0 R15: 0000000000000004
 </TASK>