[v5.15] possible deadlock in ext4_xattr_inode_iget

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syzbot

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Mar 11, 2023, 7:08:48 PM3/11/23

to syzkaller...@googlegroups.com

Hello,

syzbot found the following issue on:

HEAD commit: d214f240b0f6 Linux 5.15.100
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10554988c80000
kernel config: https://syzkaller.appspot.com/x/.config?x=c5c5a36ceb954515
dashboard link: https://syzkaller.appspot.com/bug?extid=008d00e9bf75d9de62c7
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4e12037285d4/disk-d214f240.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/929d982226d5/vmlinux-d214f240.xz
kernel image: https://storage.googleapis.com/syzbot-assets/59140c032c99/bzImage-d214f240.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+008d00...@syzkaller.appspotmail.com

EXT4-fs (loop4): mounted filesystem without journal. Opts: inode_readahead_blks=0x0000000000000000,nogrpid,debug_want_extra_isize=0x0000000000000066,dioread_nolock,max_batch_time=0x0000000000000008,resgid=0x0000000000000000,,errors=continue. Quota mode: writeback.
======================================================
WARNING: possible circular locking dependency detected
5.15.100-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.4/15254 is trying to acquire lock:
ffff888027be8de8 (&ea_inode->i_rwsem#9/1){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
ffff888027be8de8 (&ea_inode->i_rwsem#9/1){+.+.}-{3:3}, at: ext4_xattr_inode_iget+0x3d3/0x4e0 fs/ext4/xattr.c:427

but task is already holding lock:
ffff888027bea060 (&ei->i_data_sem){++++}-{3:3}, at: ext4_setattr+0x1322/0x1990 fs/ext4/inode.c:5483

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&ei->i_data_sem){++++}-{3:3}:
lock_acquire+0x1ff/0x570 kernel/locking/lockdep.c:5622
down_write+0x97/0x170 kernel/locking/rwsem.c:1541
ext4_update_i_disksize fs/ext4/ext4.h:3407 [inline]
ext4_xattr_inode_write fs/ext4/xattr.c:1402 [inline]
ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1551 [inline]
ext4_xattr_set_entry+0x3187/0x3c00 fs/ext4/xattr.c:1675
ext4_xattr_ibody_set+0x11d/0x330 fs/ext4/xattr.c:2227
ext4_xattr_set_handle+0xc72/0x1560 fs/ext4/xattr.c:2384
ext4_xattr_set+0x231/0x3d0 fs/ext4/xattr.c:2497
__vfs_setxattr+0x3e7/0x420 fs/xattr.c:182
__vfs_setxattr_noperm+0x12a/0x5e0 fs/xattr.c:216
vfs_setxattr+0x21d/0x420 fs/xattr.c:303
do_setxattr fs/xattr.c:588 [inline]
setxattr+0x27e/0x2e0 fs/xattr.c:611
path_setxattr+0x1bc/0x2a0 fs/xattr.c:630
__do_sys_setxattr fs/xattr.c:646 [inline]
__se_sys_setxattr fs/xattr.c:642 [inline]
__x64_sys_setxattr+0xb7/0xd0 fs/xattr.c:642
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x61/0xcb

-> #0 (&ea_inode->i_rwsem#9/1){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain+0x1646/0x58b0 kernel/locking/lockdep.c:3787
__lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5011
lock_acquire+0x1ff/0x570 kernel/locking/lockdep.c:5622
down_write+0x97/0x170 kernel/locking/rwsem.c:1541
inode_lock include/linux/fs.h:787 [inline]
ext4_xattr_inode_iget+0x3d3/0x4e0 fs/ext4/xattr.c:427
ext4_xattr_inode_get+0x17d/0x9a0 fs/ext4/xattr.c:490
ext4_xattr_move_to_block fs/ext4/xattr.c:2578 [inline]
ext4_xattr_make_inode_space fs/ext4/xattr.c:2680 [inline]
ext4_expand_extra_isize_ea+0xec9/0x1bd0 fs/ext4/xattr.c:2772
__ext4_expand_extra_isize+0x2f7/0x3d0 fs/ext4/inode.c:5825
ext4_try_to_expand_extra_isize fs/ext4/inode.c:5868 [inline]
__ext4_mark_inode_dirty+0x5e6/0x920 fs/ext4/inode.c:5946
ext4_setattr+0x13b0/0x1990 fs/ext4/inode.c:5486
notify_change+0xdad/0x1060 fs/attr.c:426
do_truncate+0x217/0x300 fs/open.c:65
handle_truncate fs/namei.c:3136 [inline]
do_open fs/namei.c:3484 [inline]
path_openat+0x2866/0x2ee0 fs/namei.c:3615
do_filp_open+0x21c/0x460 fs/namei.c:3642
do_sys_openat2+0x13b/0x500 fs/open.c:1211
do_sys_open fs/open.c:1227 [inline]
__do_sys_creat fs/open.c:1301 [inline]
__se_sys_creat fs/open.c:1295 [inline]
__x64_sys_creat+0x11f/0x160 fs/open.c:1295
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x61/0xcb

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&ei->i_data_sem);
lock(&ea_inode->i_rwsem#9/1);
lock(&ei->i_data_sem);
lock(&ea_inode->i_rwsem#9/1);

*** DEADLOCK ***

5 locks held by syz-executor.4/15254:
#0: ffff888046c28460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:377
#1: ffff888027bea1d8 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
#1: ffff888027bea1d8 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: do_truncate+0x203/0x300 fs/open.c:63
#2: ffff888027bea378 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
#2: ffff888027bea378 (mapping.invalidate_lock){++++}-{3:3}, at: ext4_setattr+0xdaa/0x1990 fs/ext4/inode.c:5443
#3: ffff888027bea060 (&ei->i_data_sem){++++}-{3:3}, at: ext4_setattr+0x1322/0x1990 fs/ext4/inode.c:5483
#4: ffff888027be9eb0 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_trylock_xattr fs/ext4/xattr.h:162 [inline]
#4: ffff888027be9eb0 (&ei->xattr_sem){++++}-{3:3}, at: ext4_try_to_expand_extra_isize fs/ext4/inode.c:5865 [inline]
#4: ffff888027be9eb0 (&ei->xattr_sem){++++}-{3:3}, at: __ext4_mark_inode_dirty+0x540/0x920 fs/ext4/inode.c:5946

stack backtrace:
CPU: 0 PID: 15254 Comm: syz-executor.4 Not tainted 5.15.100-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
check_noncircular+0x2f8/0x3b0 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+0x1646/0x58b0 kernel/locking/lockdep.c:3787
__lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5011
lock_acquire+0x1ff/0x570 kernel/locking/lockdep.c:5622
down_write+0x97/0x170 kernel/locking/rwsem.c:1541
inode_lock include/linux/fs.h:787 [inline]
ext4_xattr_inode_iget+0x3d3/0x4e0 fs/ext4/xattr.c:427
ext4_xattr_inode_get+0x17d/0x9a0 fs/ext4/xattr.c:490
ext4_xattr_move_to_block fs/ext4/xattr.c:2578 [inline]
ext4_xattr_make_inode_space fs/ext4/xattr.c:2680 [inline]
ext4_expand_extra_isize_ea+0xec9/0x1bd0 fs/ext4/xattr.c:2772
__ext4_expand_extra_isize+0x2f7/0x3d0 fs/ext4/inode.c:5825
ext4_try_to_expand_extra_isize fs/ext4/inode.c:5868 [inline]
__ext4_mark_inode_dirty+0x5e6/0x920 fs/ext4/inode.c:5946
ext4_setattr+0x13b0/0x1990 fs/ext4/inode.c:5486
notify_change+0xdad/0x1060 fs/attr.c:426
do_truncate+0x217/0x300 fs/open.c:65
handle_truncate fs/namei.c:3136 [inline]
do_open fs/namei.c:3484 [inline]
path_openat+0x2866/0x2ee0 fs/namei.c:3615
do_filp_open+0x21c/0x460 fs/namei.c:3642
do_sys_openat2+0x13b/0x500 fs/open.c:1211
do_sys_open fs/open.c:1227 [inline]
__do_sys_creat fs/open.c:1301 [inline]
__se_sys_creat fs/open.c:1295 [inline]
__x64_sys_creat+0x11f/0x160 fs/open.c:1295
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fe17def40f9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 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:00007fe17c466168 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007fe17e013f80 RCX: 00007fe17def40f9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000000
RBP: 00007fe17df4fae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff4d61f67f R14: 00007fe17c466300 R15: 0000000000022000
</TASK>

---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

syzbot

unread,

Mar 12, 2023, 6:40:43 AM3/12/23

to syzkaller...@googlegroups.com

Hello,

syzbot found the following issue on:

HEAD commit: 1cc3fcf63192 Linux 6.1.18
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17432d42c80000
kernel config: https://syzkaller.appspot.com/x/.config?x=ac04a15f4a80e9d0
dashboard link: https://syzkaller.appspot.com/bug?extid=7ea78cee4928af04294d

compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2

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

Downloadable assets:

disk image: https://storage.googleapis.com/syzbot-assets/9dee98921f5a/disk-1cc3fcf6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/713a648558bd/vmlinux-1cc3fcf6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6b9e84fcf1df/bzImage-1cc3fcf6.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:

Reported-by: syzbot+7ea78c...@syzkaller.appspotmail.com

EXT4-fs (loop1): 1 truncate cleaned up
EXT4-fs (loop1): mounted filesystem without journal. Quota mode: writeback.

======================================================
WARNING: possible circular locking dependency detected

6.1.18-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.1/16900 is trying to acquire lock:
ffff8880754ed440 (&ea_inode->i_rwsem#8/1){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline]
ffff8880754ed440 (&ea_inode->i_rwsem#8/1){+.+.}-{3:3}, at: ext4_xattr_inode_iget+0x3d3/0x4e0 fs/ext4/xattr.c:427

but task is already holding lock:

ffff8880754e9698 (&ei->i_data_sem){++++}-{3:3}, at: ext4_setattr+0x13fa/0x1a00 fs/ext4/inode.c:5515

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&ei->i_data_sem){++++}-{3:3}:

lock_acquire+0x23a/0x630 kernel/locking/lockdep.c:5669
down_write+0x36/0x60 kernel/locking/rwsem.c:1573
ext4_update_i_disksize fs/ext4/ext4.h:3383 [inline]

ext4_xattr_inode_write fs/ext4/xattr.c:1402 [inline]
ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1551 [inline]
ext4_xattr_set_entry+0x3187/0x3c00 fs/ext4/xattr.c:1675
ext4_xattr_ibody_set+0x11d/0x330 fs/ext4/xattr.c:2227
ext4_xattr_set_handle+0xc72/0x1560 fs/ext4/xattr.c:2384

ext4_xattr_set+0x231/0x3d0 fs/ext4/xattr.c:2498

__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_setxattr fs/xattr.c:652 [inline]
__se_sys_setxattr fs/xattr.c:648 [inline]
__x64_sys_setxattr+0xb7/0xd0 fs/xattr.c:648

do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80

entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (&ea_inode->i_rwsem#8/1){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3098 [inline]
check_prevs_add kernel/locking/lockdep.c:3217 [inline]
validate_chain+0x1667/0x58e0 kernel/locking/lockdep.c:3832
__lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056
lock_acquire+0x23a/0x630 kernel/locking/lockdep.c:5669
down_write+0x36/0x60 kernel/locking/rwsem.c:1573
inode_lock include/linux/fs.h:756 [inline]

ext4_xattr_inode_iget+0x3d3/0x4e0 fs/ext4/xattr.c:427
ext4_xattr_inode_get+0x17d/0x9a0 fs/ext4/xattr.c:490

ext4_xattr_move_to_block fs/ext4/xattr.c:2579 [inline]
ext4_xattr_make_inode_space fs/ext4/xattr.c:2681 [inline]
ext4_expand_extra_isize_ea+0xec9/0x1bd0 fs/ext4/xattr.c:2773
__ext4_expand_extra_isize+0x2f7/0x3d0 fs/ext4/inode.c:5887
ext4_try_to_expand_extra_isize fs/ext4/inode.c:5930 [inline]
__ext4_mark_inode_dirty+0x60a/0x9d0 fs/ext4/inode.c:6008
ext4_setattr+0x1493/0x1a00 fs/ext4/inode.c:5518
notify_change+0xdcd/0x1080 fs/attr.c:482
do_truncate+0x21c/0x300 fs/open.c:65
handle_truncate fs/namei.c:3216 [inline]
do_open fs/namei.c:3561 [inline]
path_openat+0x27e2/0x2e60 fs/namei.c:3714
do_filp_open+0x230/0x480 fs/namei.c:3741
do_sys_openat2+0x13b/0x500 fs/open.c:1310
do_sys_open fs/open.c:1326 [inline]
__do_sys_creat fs/open.c:1402 [inline]
__se_sys_creat fs/open.c:1396 [inline]
__x64_sys_creat+0x11f/0x160 fs/open.c:1396

do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80

entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&ei->i_data_sem);

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

*** DEADLOCK ***

5 locks held by syz-executor.1/16900:
#0: ffff888028ada460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:393
#1: ffff8880754e9810 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline]
#1: ffff8880754e9810 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: do_truncate+0x208/0x300 fs/open.c:63
#2: ffff8880754e99b0 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:801 [inline]
#2: ffff8880754e99b0 (mapping.invalidate_lock){++++}-{3:3}, at: ext4_setattr+0xec7/0x1a00 fs/ext4/inode.c:5475
#3: ffff8880754e9698 (&ei->i_data_sem){++++}-{3:3}, at: ext4_setattr+0x13fa/0x1a00 fs/ext4/inode.c:5515
#4: ffff8880754e94d8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_trylock_xattr fs/ext4/xattr.h:162 [inline]
#4: ffff8880754e94d8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_try_to_expand_extra_isize fs/ext4/inode.c:5927 [inline]
#4: ffff8880754e94d8 (&ei->xattr_sem){++++}-{3:3}, at: __ext4_mark_inode_dirty+0x56b/0x9d0 fs/ext4/inode.c:6008

stack backtrace:
CPU: 1 PID: 16900 Comm: syz-executor.1 Not tainted 6.1.18-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
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:2178
check_prev_add kernel/locking/lockdep.c:3098 [inline]
check_prevs_add kernel/locking/lockdep.c:3217 [inline]
validate_chain+0x1667/0x58e0 kernel/locking/lockdep.c:3832
__lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056
lock_acquire+0x23a/0x630 kernel/locking/lockdep.c:5669
down_write+0x36/0x60 kernel/locking/rwsem.c:1573
inode_lock include/linux/fs.h:756 [inline]

ext4_xattr_inode_iget+0x3d3/0x4e0 fs/ext4/xattr.c:427
ext4_xattr_inode_get+0x17d/0x9a0 fs/ext4/xattr.c:490

do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80

entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fdaa608c0f9

Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 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:00007fdaa6d91168 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007fdaa61abf80 RCX: 00007fdaa608c0f9

RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000000

RBP: 00007fdaa60e7ae9 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 00007ffeca120abf R14: 00007fdaa6d91300 R15: 0000000000022000

syzbot

unread,

May 7, 2023, 11:29:51 PM5/7/23

to syzkaller...@googlegroups.com

syzbot has found a reproducer for the following issue on:

HEAD commit: 8a7f2a5c5aa1 Linux 5.15.110
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=13c214dc280000
kernel config: https://syzkaller.appspot.com/x/.config?x=ba8d5c9d6c5289f

dashboard link: https://syzkaller.appspot.com/bug?extid=008d00e9bf75d9de62c7
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1316c4dc280000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11d828b8280000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/fc04f54c047f/disk-8a7f2a5c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6b4ba4cb1191/vmlinux-8a7f2a5c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d927dc3f9670/bzImage-8a7f2a5c.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/77e8c6b9892f/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+008d00...@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 512
EXT4-fs (loop0): Warning: mounting with an experimental mount option 'dioread_nolock' for blocksize < PAGE_SIZE
EXT4-fs (loop0): 1 truncate cleaned up
EXT4-fs (loop0): mounted filesystem without journal. Opts: inode_readahead_blks=0x0000000000000000,nogrpid,debug_want_extra_isize=0x0000000000000066,dioread_nolock,max_batch_time=0x0000000000000008,resgid=0x0000000000000000,,errors=continue. Quota mode: writeback.

======================================================
WARNING: possible circular locking dependency detected

5.15.110-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor307/3497 is trying to acquire lock:
ffff888074d45da8 (&ea_inode->i_rwsem#9/1){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
ffff888074d45da8 (&ea_inode->i_rwsem#9/1){+.+.}-{3:3}, at: ext4_xattr_inode_iget+0x4a3/0x5e0 fs/ext4/xattr.c:438

but task is already holding lock:

ffff888074d45238 (&ei->i_data_sem){++++}-{3:3}, at: ext4_setattr+0x1322/0x1990 fs/ext4/inode.c:5486

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&ei->i_data_sem){++++}-{3:3}:

lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622

down_write+0x97/0x170 kernel/locking/rwsem.c:1541
ext4_update_i_disksize fs/ext4/ext4.h:3407 [inline]

ext4_xattr_inode_write fs/ext4/xattr.c:1413 [inline]
ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1562 [inline]
ext4_xattr_set_entry+0x3187/0x3c00 fs/ext4/xattr.c:1686
ext4_xattr_ibody_set+0x11d/0x330 fs/ext4/xattr.c:2238
ext4_xattr_set_handle+0xc72/0x1560 fs/ext4/xattr.c:2395
ext4_xattr_set+0x231/0x3d0 fs/ext4/xattr.c:2508

__vfs_setxattr+0x3e7/0x420 fs/xattr.c:182
__vfs_setxattr_noperm+0x12a/0x5e0 fs/xattr.c:216
vfs_setxattr+0x21d/0x420 fs/xattr.c:303
do_setxattr fs/xattr.c:588 [inline]
setxattr+0x27e/0x2e0 fs/xattr.c:611
path_setxattr+0x1bc/0x2a0 fs/xattr.c:630
__do_sys_setxattr fs/xattr.c:646 [inline]
__se_sys_setxattr fs/xattr.c:642 [inline]
__x64_sys_setxattr+0xb7/0xd0 fs/xattr.c:642
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x61/0xcb

-> #0 (&ea_inode->i_rwsem#9/1){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain+0x1646/0x58b0 kernel/locking/lockdep.c:3787
__lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5011

lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622

down_write+0x97/0x170 kernel/locking/rwsem.c:1541
inode_lock include/linux/fs.h:787 [inline]

ext4_xattr_inode_iget+0x4a3/0x5e0 fs/ext4/xattr.c:438
ext4_xattr_inode_get+0x17d/0x9a0 fs/ext4/xattr.c:501
ext4_xattr_move_to_block fs/ext4/xattr.c:2589 [inline]
ext4_xattr_make_inode_space fs/ext4/xattr.c:2691 [inline]
ext4_expand_extra_isize_ea+0xe77/0x1bc0 fs/ext4/xattr.c:2783
__ext4_expand_extra_isize+0x2f7/0x3d0 fs/ext4/inode.c:5828
ext4_try_to_expand_extra_isize fs/ext4/inode.c:5871 [inline]
__ext4_mark_inode_dirty+0x539/0x860 fs/ext4/inode.c:5949
ext4_setattr+0x13b0/0x1990 fs/ext4/inode.c:5489
notify_change+0xd4d/0x1000 fs/attr.c:488
do_truncate+0x21c/0x300 fs/open.c:65
handle_truncate fs/namei.c:3195 [inline]
do_open fs/namei.c:3542 [inline]
path_openat+0x28a0/0x2f20 fs/namei.c:3672
do_filp_open+0x21c/0x460 fs/namei.c:3699

do_sys_openat2+0x13b/0x500 fs/open.c:1211
do_sys_open fs/open.c:1227 [inline]
__do_sys_creat fs/open.c:1301 [inline]
__se_sys_creat fs/open.c:1295 [inline]
__x64_sys_creat+0x11f/0x160 fs/open.c:1295
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x61/0xcb

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&ei->i_data_sem);
lock(&ea_inode->i_rwsem#9/1);
lock(&ei->i_data_sem);
lock(&ea_inode->i_rwsem#9/1);

*** DEADLOCK ***

5 locks held by syz-executor307/3497:
#0: ffff888015da6460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:377
#1: ffff888074d453b0 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
#1: ffff888074d453b0 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: do_truncate+0x208/0x300 fs/open.c:63
#2: ffff888074d45550 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
#2: ffff888074d45550 (mapping.invalidate_lock){++++}-{3:3}, at: ext4_setattr+0xdaa/0x1990 fs/ext4/inode.c:5446
#3: ffff888074d45238 (&ei->i_data_sem){++++}-{3:3}, at: ext4_setattr+0x1322/0x1990 fs/ext4/inode.c:5486
#4: ffff888074d45088 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_trylock_xattr fs/ext4/xattr.h:162 [inline]
#4: ffff888074d45088 (&ei->xattr_sem){++++}-{3:3}, at: ext4_try_to_expand_extra_isize fs/ext4/inode.c:5868 [inline]
#4: ffff888074d45088 (&ei->xattr_sem){++++}-{3:3}, at: __ext4_mark_inode_dirty+0x4a0/0x860 fs/ext4/inode.c:5949

stack backtrace:
CPU: 1 PID: 3497 Comm: syz-executor307 Not tainted 5.15.110-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023

Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
check_noncircular+0x2f8/0x3b0 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+0x1646/0x58b0 kernel/locking/lockdep.c:3787
__lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5011

lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622

down_write+0x97/0x170 kernel/locking/rwsem.c:1541
inode_lock include/linux/fs.h:787 [inline]

RIP: 0033:0x7fb3256a0c29
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 14 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc984d49d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda

---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

syzbot

unread,

May 8, 2023, 12:41:39 AM5/8/23

to syzkaller...@googlegroups.com

syzbot has found a reproducer for the following issue on:

HEAD commit: ca48fc16c493 Linux 6.1.27
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14f3a1f4280000
kernel config: https://syzkaller.appspot.com/x/.config?x=47d3bbfdb3b1ddd2

dashboard link: https://syzkaller.appspot.com/bug?extid=7ea78cee4928af04294d
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1750fb12280000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16b96382280000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/658765c915fa/disk-ca48fc16.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d69e8a1aff2d/vmlinux-ca48fc16.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0317a9546209/bzImage-ca48fc16.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/13b6c0f4d25c/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7ea78c...@syzkaller.appspotmail.com

EXT4-fs: Warning: mounting with an experimental mount option 'dioread_nolock' for blocksize < PAGE_SIZE
EXT4-fs (loop0): 1 truncate cleaned up
EXT4-fs (loop0): mounted filesystem without journal. Quota mode: writeback.

======================================================
WARNING: possible circular locking dependency detected

6.1.27-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor294/3541 is trying to acquire lock:
ffff888073145440 (&ea_inode->i_rwsem#8/1){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline]
ffff888073145440 (&ea_inode->i_rwsem#8/1){+.+.}-{3:3}, at: ext4_xattr_inode_iget+0x4a3/0x5e0 fs/ext4/xattr.c:438

but task is already holding lock:

ffff8880731448c0 (&ei->i_data_sem){++++}-{3:3}, at: ext4_setattr+0x13fa/0x1a00 fs/ext4/inode.c:5518

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&ei->i_data_sem){++++}-{3:3}:

lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669

down_write+0x36/0x60 kernel/locking/rwsem.c:1573
ext4_update_i_disksize fs/ext4/ext4.h:3383 [inline]

ext4_xattr_set+0x231/0x3d0 fs/ext4/xattr.c:2509

__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_setxattr fs/xattr.c:652 [inline]
__se_sys_setxattr fs/xattr.c:648 [inline]
__x64_sys_setxattr+0xb7/0xd0 fs/xattr.c:648
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (&ea_inode->i_rwsem#8/1){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3098 [inline]
check_prevs_add kernel/locking/lockdep.c:3217 [inline]
validate_chain+0x1667/0x58e0 kernel/locking/lockdep.c:3832
__lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056

lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669

down_write+0x36/0x60 kernel/locking/rwsem.c:1573
inode_lock include/linux/fs.h:756 [inline]

ext4_xattr_inode_iget+0x4a3/0x5e0 fs/ext4/xattr.c:438
ext4_xattr_inode_get+0x17d/0x9a0 fs/ext4/xattr.c:501

ext4_xattr_move_to_block fs/ext4/xattr.c:2590 [inline]
ext4_xattr_make_inode_space fs/ext4/xattr.c:2692 [inline]
ext4_expand_extra_isize_ea+0xe77/0x1bc0 fs/ext4/xattr.c:2784
__ext4_expand_extra_isize+0x2f7/0x3d0 fs/ext4/inode.c:5890
ext4_try_to_expand_extra_isize fs/ext4/inode.c:5933 [inline]
__ext4_mark_inode_dirty+0x54f/0x920 fs/ext4/inode.c:6011
ext4_setattr+0x1493/0x1a00 fs/ext4/inode.c:5521

notify_change+0xdcd/0x1080 fs/attr.c:482
do_truncate+0x21c/0x300 fs/open.c:65
handle_truncate fs/namei.c:3216 [inline]
do_open fs/namei.c:3561 [inline]
path_openat+0x27e2/0x2e60 fs/namei.c:3714
do_filp_open+0x230/0x480 fs/namei.c:3741
do_sys_openat2+0x13b/0x500 fs/open.c:1310
do_sys_open fs/open.c:1326 [inline]
__do_sys_creat fs/open.c:1402 [inline]
__se_sys_creat fs/open.c:1396 [inline]
__x64_sys_creat+0x11f/0x160 fs/open.c:1396
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Possible unsafe locking scenario:

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

*** DEADLOCK ***

5 locks held by syz-executor294/3541:
#0: ffff88807b46a460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:393
#1: ffff888073144a38 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline]
#1: ffff888073144a38 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: do_truncate+0x208/0x300 fs/open.c:63
#2: ffff888073144bd8 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:801 [inline]
#2: ffff888073144bd8 (mapping.invalidate_lock){++++}-{3:3}, at: ext4_setattr+0xec7/0x1a00 fs/ext4/inode.c:5478
#3: ffff8880731448c0 (&ei->i_data_sem){++++}-{3:3}, at: ext4_setattr+0x13fa/0x1a00 fs/ext4/inode.c:5518
#4: ffff888073144700 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_trylock_xattr fs/ext4/xattr.h:162 [inline]
#4: ffff888073144700 (&ei->xattr_sem){++++}-{3:3}, at: ext4_try_to_expand_extra_isize fs/ext4/inode.c:5930 [inline]
#4: ffff888073144700 (&ei->xattr_sem){++++}-{3:3}, at: __ext4_mark_inode_dirty+0x4b0/0x920 fs/ext4/inode.c:6011

stack backtrace:
CPU: 1 PID: 3541 Comm: syz-executor294 Not tainted 6.1.27-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023

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:2178
check_prev_add kernel/locking/lockdep.c:3098 [inline]
check_prevs_add kernel/locking/lockdep.c:3217 [inline]
validate_chain+0x1667/0x58e0 kernel/locking/lockdep.c:3832
__lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056

lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669

down_write+0x36/0x60 kernel/locking/rwsem.c:1573
inode_lock include/linux/fs.h:756 [inline]

ext4_xattr_inode_iget+0x4a3/0x5e0 fs/ext4/xattr.c:438
ext4_xattr_inode_get+0x17d/0x9a0 fs/ext4/xattr.c:501

RIP: 0033:0x7f7d36a45c59
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 14 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe3bff7dc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 0031656c69662f2e RCX: 00007f7d36a45c59
RDX: 00007f7d36a45c59 RSI: 0000000000000000 RDI: 0000000020000080
RBP: 00007f7d36a05260 R08: 0000000000000000 R09: 0000000000000000

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