[v6.1] possible deadlock in ext4_xattr_inode_lookup_create

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 7c15117f9468 Linux 6.1.115
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10a386a7980000
kernel config: https://syzkaller.appspot.com/x/.config?x=c9c0221b8515082d
dashboard link: https://syzkaller.appspot.com/bug?extid=aa8811dc2a41ca80316e
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d43a49ab45a4/disk-7c15117f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d1169a6dd6d5/vmlinux-7c15117f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/cac0c99432c7/bzImage-7c15117f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+aa8811...@syzkaller.appspotmail.com

EXT4-fs (loop3): encrypted files will use data=ordered instead of data journaling mode
EXT4-fs (loop3): 1 truncate cleaned up
EXT4-fs (loop3): mounted filesystem without journal. Quota mode: writeback.
======================================================
WARNING: possible circular locking dependency detected
6.1.115-syzkaller #0 Not tainted
------------------------------------------------------
syz.3.541/6491 is trying to acquire lock:
ffff88805812de48 (&ea_inode->i_rwsem#8/1){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
ffff88805812de48 (&ea_inode->i_rwsem#8/1){+.+.}-{3:3}, at: ext4_xattr_inode_create fs/ext4/xattr.c:1465 [inline]
ffff88805812de48 (&ea_inode->i_rwsem#8/1){+.+.}-{3:3}, at: ext4_xattr_inode_lookup_create+0x1a21/0x1ef0 fs/ext4/xattr.c:1547

but task is already holding lock:
ffff8880743f8c90 (&ei->i_data_sem/3){++++}-{3:3}, at: ext4_setattr+0x13fa/0x1a00 fs/ext4/inode.c:5564

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&ei->i_data_sem/3){++++}-{3:3}:
lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
down_write+0x36/0x60 kernel/locking/rwsem.c:1573
ext4_update_i_disksize fs/ext4/ext4.h:3377 [inline]
ext4_xattr_inode_write fs/ext4/xattr.c:1403 [inline]
ext4_xattr_inode_lookup_create+0x16ac/0x1ef0 fs/ext4/xattr.c:1553
ext4_xattr_ibody_set+0x210/0x720 fs/ext4/xattr.c:2215
ext4_xattr_set_handle+0xc72/0x1560 fs/ext4/xattr.c:2392
ext4_xattr_set+0x26e/0x3d0 fs/ext4/xattr.c:2506
__vfs_setxattr+0x3e7/0x420 fs/xattr.c:182
__vfs_setxattr_noperm+0x12a/0x5e0 fs/xattr.c:216
vfs_setxattr+0x21d/0x420 fs/xattr.c:309
do_setxattr fs/xattr.c:594 [inline]
setxattr+0x250/0x2b0 fs/xattr.c:617
path_setxattr+0x1bc/0x2a0 fs/xattr.c:636
__do_sys_lsetxattr fs/xattr.c:659 [inline]
__se_sys_lsetxattr fs/xattr.c:655 [inline]
__x64_sys_lsetxattr+0xb4/0xd0 fs/xattr.c:655
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (&ea_inode->i_rwsem#8/1){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3090 [inline]
check_prevs_add kernel/locking/lockdep.c:3209 [inline]
validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825
__lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
down_write+0x36/0x60 kernel/locking/rwsem.c:1573
inode_lock include/linux/fs.h:758 [inline]
ext4_xattr_inode_create fs/ext4/xattr.c:1465 [inline]
ext4_xattr_inode_lookup_create+0x1a21/0x1ef0 fs/ext4/xattr.c:1547
ext4_xattr_block_set+0x2a1/0x3920 fs/ext4/xattr.c:1867
ext4_xattr_move_to_block fs/ext4/xattr.c:2616 [inline]
ext4_xattr_make_inode_space fs/ext4/xattr.c:2691 [inline]
ext4_expand_extra_isize_ea+0x10d5/0x1bb0 fs/ext4/xattr.c:2783
__ext4_expand_extra_isize+0x2f7/0x3d0 fs/ext4/inode.c:5936
ext4_try_to_expand_extra_isize fs/ext4/inode.c:5979 [inline]
__ext4_mark_inode_dirty+0x54f/0x920 fs/ext4/inode.c:6057
ext4_setattr+0x1493/0x1a00 fs/ext4/inode.c:5567
notify_change+0xce3/0xfc0 fs/attr.c:499
do_truncate+0x21c/0x300 fs/open.c:65
handle_truncate fs/namei.c:3285 [inline]
do_open fs/namei.c:3630 [inline]
path_openat+0x27e2/0x2e60 fs/namei.c:3783
do_filp_open+0x230/0x480 fs/namei.c:3810
do_sys_openat2+0x13b/0x4f0 fs/open.c:1318
do_sys_open fs/open.c:1334 [inline]
__do_sys_creat fs/open.c:1412 [inline]
__se_sys_creat fs/open.c:1406 [inline]
__x64_sys_creat+0x11f/0x160 fs/open.c:1406
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&ei->i_data_sem/3);
lock(&ea_inode->i_rwsem#8/1);
lock(&ei->i_data_sem/3);
lock(&ea_inode->i_rwsem#8/1);

*** DEADLOCK ***

5 locks held by syz.3.541/6491:
#0: ffff888074a76460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:393
#1: ffff8880743f8e08 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
#1: ffff8880743f8e08 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: do_truncate+0x208/0x300 fs/open.c:63
#2: ffff8880743f8fa8 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
#2: ffff8880743f8fa8 (mapping.invalidate_lock){++++}-{3:3}, at: ext4_setattr+0xec7/0x1a00 fs/ext4/inode.c:5524
#3: ffff8880743f8c90 (&ei->i_data_sem/3){++++}-{3:3}, at: ext4_setattr+0x13fa/0x1a00 fs/ext4/inode.c:5564
#4: ffff8880743f8ad0 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_trylock_xattr fs/ext4/xattr.h:162 [inline]
#4: ffff8880743f8ad0 (&ei->xattr_sem){++++}-{3:3}, at: ext4_try_to_expand_extra_isize fs/ext4/inode.c:5976 [inline]
#4: ffff8880743f8ad0 (&ei->xattr_sem){++++}-{3:3}, at: __ext4_mark_inode_dirty+0x4b0/0x920 fs/ext4/inode.c:6057

stack backtrace:
CPU: 0 PID: 6491 Comm: syz.3.541 Not tainted 6.1.115-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
check_noncircular+0x2fa/0x3b0 kernel/locking/lockdep.c:2170
check_prev_add kernel/locking/lockdep.c:3090 [inline]
check_prevs_add kernel/locking/lockdep.c:3209 [inline]
validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825
__lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
down_write+0x36/0x60 kernel/locking/rwsem.c:1573
inode_lock include/linux/fs.h:758 [inline]
ext4_xattr_inode_create fs/ext4/xattr.c:1465 [inline]
ext4_xattr_inode_lookup_create+0x1a21/0x1ef0 fs/ext4/xattr.c:1547
ext4_xattr_block_set+0x2a1/0x3920 fs/ext4/xattr.c:1867
ext4_xattr_move_to_block fs/ext4/xattr.c:2616 [inline]
ext4_xattr_make_inode_space fs/ext4/xattr.c:2691 [inline]
ext4_expand_extra_isize_ea+0x10d5/0x1bb0 fs/ext4/xattr.c:2783
__ext4_expand_extra_isize+0x2f7/0x3d0 fs/ext4/inode.c:5936
ext4_try_to_expand_extra_isize fs/ext4/inode.c:5979 [inline]
__ext4_mark_inode_dirty+0x54f/0x920 fs/ext4/inode.c:6057
ext4_setattr+0x1493/0x1a00 fs/ext4/inode.c:5567
notify_change+0xce3/0xfc0 fs/attr.c:499
do_truncate+0x21c/0x300 fs/open.c:65
handle_truncate fs/namei.c:3285 [inline]
do_open fs/namei.c:3630 [inline]
path_openat+0x27e2/0x2e60 fs/namei.c:3783
do_filp_open+0x230/0x480 fs/namei.c:3810
do_sys_openat2+0x13b/0x4f0 fs/open.c:1318
do_sys_open fs/open.c:1334 [inline]
__do_sys_creat fs/open.c:1412 [inline]
__se_sys_creat fs/open.c:1406 [inline]
__x64_sys_creat+0x11f/0x160 fs/open.c:1406
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fce51f7e719
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:00007fce52dd5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007fce52136058 RCX: 00007fce51f7e719
RDX: 0000000000000000 RSI: 000000000000013d RDI: 0000000020000140
RBP: 00007fce51ff132e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fce52136058 R15: 00007ffdaa954c78
</TASK>


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 7c15117f9468 Linux 6.1.115
git tree: linux-6.1.y

console output: https://syzkaller.appspot.com/x/log.txt?x=13e32d5f980000

kernel config: https://syzkaller.appspot.com/x/.config?x=c9c0221b8515082d
dashboard link: https://syzkaller.appspot.com/bug?extid=aa8811dc2a41ca80316e
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=154ca587980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17a786a7980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d43a49ab45a4/disk-7c15117f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d1169a6dd6d5/vmlinux-7c15117f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/cac0c99432c7/bzImage-7c15117f.xz

mounted in repro: https://storage.googleapis.com/syzbot-assets/c30e1b3c15d8/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+aa8811...@syzkaller.appspotmail.com

EXT4-fs (loop0): encrypted files will use data=ordered instead of data journaling mode
EXT4-fs (loop0): 1 truncate cleaned up

======================================================
WARNING: possible circular locking dependency detected
6.1.115-syzkaller #0 Not tainted
------------------------------------------------------

syz-executor193/4373 is trying to acquire lock:
ffff888071bbb628 (&ea_inode->i_rwsem#8/1){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
ffff888071bbb628 (&ea_inode->i_rwsem#8/1){+.+.}-{3:3}, at: ext4_xattr_inode_create fs/ext4/xattr.c:1465 [inline]
ffff888071bbb628 (&ea_inode->i_rwsem#8/1){+.+.}-{3:3}, at: ext4_xattr_inode_lookup_create+0x1a21/0x1ef0 fs/ext4/xattr.c:1547

but task is already holding lock:

ffff888071bbe6d8 (&ei->i_data_sem/3){++++}-{3:3}, at: ext4_setattr+0x13fa/0x1a00 fs/ext4/inode.c:5564

5 locks held by syz-executor193/4373:
#0: ffff88807c67c460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:393
#1: ffff888071bbe850 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
#1: ffff888071bbe850 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: do_truncate+0x208/0x300 fs/open.c:63
#2: ffff888071bbe9f0 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
#2: ffff888071bbe9f0 (mapping.invalidate_lock){++++}-{3:3}, at: ext4_setattr+0xec7/0x1a00 fs/ext4/inode.c:5524
#3: ffff888071bbe6d8 (&ei->i_data_sem/3){++++}-{3:3}, at: ext4_setattr+0x13fa/0x1a00 fs/ext4/inode.c:5564
#4: ffff888071bbe518 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_trylock_xattr fs/ext4/xattr.h:162 [inline]
#4: ffff888071bbe518 (&ei->xattr_sem){++++}-{3:3}, at: ext4_try_to_expand_extra_isize fs/ext4/inode.c:5976 [inline]
#4: ffff888071bbe518 (&ei->xattr_sem){++++}-{3:3}, at: __ext4_mark_inode_dirty+0x4b0/0x920 fs/ext4/inode.c:6057

stack backtrace:
CPU: 1 PID: 4373 Comm: syz-executor193 Not tainted 6.1.115-syzkaller #0

RIP: 0033:0x7f1dc5e67269
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 21 18 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe18693a18 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 0031656c69662f2e RCX: 00007f1dc5e67269
RDX: 00007f1dc5e67269 RSI: 000000000000013d RDI: 0000000020000140
RBP: 0000000000000000 R08: 00007ffe18693a50 R09: 00007ffe18693a50
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe18693a3c
R13: 000000000000003e R14: 431bde82d7b634db R15: 00007ffe18693a70
</TASK>


---
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