[syzbot] [ext4?] possible deadlock in ext4_xattr_set_handle (6)

From: syzbot
Date: Wed Oct 02 2024 - 05:48:36 EST

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Hello,

syzbot found the following issue on:

HEAD commit: e32cde8d2bd7 Merge tag 'sched_ext-for-6.12-rc1-fixes-1' of..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12a6e927980000
kernel config: https://syzkaller.appspot.com/x/.config?x=8445583625becf41
dashboard link: https://syzkaller.appspot.com/bug?extid=f5fadcee2108d2f0dd2d
compiler: gcc (Debian 12.2.0-14) 12.2.0, 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/a8ab0519b64e/disk-e32cde8d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3f86df70153a/vmlinux-e32cde8d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/93df43d11421/bzImage-e32cde8d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f5fadcee2108d2f0dd2d@xxxxxxxxxxxxxxxxxxxxxxxxx

======================================================
WARNING: possible circular locking dependency detected
6.12.0-rc1-syzkaller-00031-ge32cde8d2bd7 #0 Not tainted
------------------------------------------------------
syz.0.2834/27060 is trying to acquire lock:
ffff888078f3e3d8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:154 [inline]
ffff888078f3e3d8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_xattr_set_handle+0x159/0x1420 fs/ext4/xattr.c:2373

but task is already holding lock:
ffff88807dde6958 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0xf6c/0x1430 fs/jbd2/transaction.c:448

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #5 (jbd2_handle){++++}-{0:0}:
start_this_handle+0xf92/0x1430 fs/jbd2/transaction.c:448
jbd2__journal_start+0x394/0x6a0 fs/jbd2/transaction.c:505
jbd2_journal_start+0x29/0x40 fs/jbd2/transaction.c:544
ocfs2_start_trans+0x3b9/0x970 fs/ocfs2/journal.c:352
ocfs2_modify_bh+0xbe/0x490 fs/ocfs2/quota_local.c:101
ocfs2_local_read_info+0xd68/0x1610 fs/ocfs2/quota_local.c:771
dquot_load_quota_sb+0x83d/0x1050 fs/quota/dquot.c:2458
dquot_load_quota_inode fs/quota/dquot.c:2495 [inline]
dquot_load_quota_inode+0x2a3/0x470 fs/quota/dquot.c:2487
ocfs2_enable_quotas+0x28b/0x5a0 fs/ocfs2/super.c:926
ocfs2_fill_super+0x23b4/0x4340 fs/ocfs2/super.c:1141
mount_bdev+0x1e6/0x2d0 fs/super.c:1679
legacy_get_tree+0x10c/0x220 fs/fs_context.c:662
vfs_get_tree+0x92/0x380 fs/super.c:1800
do_new_mount fs/namespace.c:3507 [inline]
path_mount+0x14e6/0x1f20 fs/namespace.c:3834
do_mount fs/namespace.c:3847 [inline]
__do_sys_mount fs/namespace.c:4055 [inline]
__se_sys_mount fs/namespace.c:4032 [inline]
__x64_sys_mount+0x294/0x320 fs/namespace.c:4032
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #4 (&journal->j_trans_barrier){.+.+}-{3:3}:
down_read+0x9a/0x330 kernel/locking/rwsem.c:1524
ocfs2_start_trans+0x3ae/0x970 fs/ocfs2/journal.c:350
ocfs2_modify_bh+0xbe/0x490 fs/ocfs2/quota_local.c:101
ocfs2_local_read_info+0xd68/0x1610 fs/ocfs2/quota_local.c:771
dquot_load_quota_sb+0x83d/0x1050 fs/quota/dquot.c:2458
dquot_load_quota_inode fs/quota/dquot.c:2495 [inline]
dquot_load_quota_inode+0x2a3/0x470 fs/quota/dquot.c:2487
ocfs2_enable_quotas+0x28b/0x5a0 fs/ocfs2/super.c:926
ocfs2_fill_super+0x23b4/0x4340 fs/ocfs2/super.c:1141
mount_bdev+0x1e6/0x2d0 fs/super.c:1679
legacy_get_tree+0x10c/0x220 fs/fs_context.c:662
vfs_get_tree+0x92/0x380 fs/super.c:1800
do_new_mount fs/namespace.c:3507 [inline]
path_mount+0x14e6/0x1f20 fs/namespace.c:3834
do_mount fs/namespace.c:3847 [inline]
__do_sys_mount fs/namespace.c:4055 [inline]
__se_sys_mount fs/namespace.c:4032 [inline]
__x64_sys_mount+0x294/0x320 fs/namespace.c:4032
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #3 (sb_internal#5){.+.+}-{0:0}:
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1716 [inline]
sb_start_intwrite include/linux/fs.h:1899 [inline]
ocfs2_start_trans+0x29d/0x970 fs/ocfs2/journal.c:348
ocfs2_acquire_dquot+0x566/0xaf0 fs/ocfs2/quota_global.c:855
dqget+0x694/0x1160 fs/quota/dquot.c:976
__dquot_initialize+0x588/0xd50 fs/quota/dquot.c:1504
ocfs2_get_init_inode+0xe8/0x1a0 fs/ocfs2/namei.c:202
ocfs2_symlink+0xbae/0x3a00 fs/ocfs2/namei.c:1886
vfs_symlink fs/namei.c:4615 [inline]
vfs_symlink+0x3eb/0x660 fs/namei.c:4599
do_symlinkat+0x263/0x310 fs/namei.c:4641
__do_sys_symlink fs/namei.c:4662 [inline]
__se_sys_symlink fs/namei.c:4660 [inline]
__x64_sys_symlink+0x75/0x90 fs/namei.c:4660
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}:
down_write+0x93/0x200 kernel/locking/rwsem.c:1577
ocfs2_create_local_dquot+0x158/0xb40 fs/ocfs2/quota_local.c:1231
ocfs2_acquire_dquot+0x629/0xaf0 fs/ocfs2/quota_global.c:878
dqget+0x694/0x1160 fs/quota/dquot.c:976
__dquot_initialize+0x588/0xd50 fs/quota/dquot.c:1504
ocfs2_get_init_inode+0xe8/0x1a0 fs/ocfs2/namei.c:202
ocfs2_symlink+0xbae/0x3a00 fs/ocfs2/namei.c:1886
vfs_symlink fs/namei.c:4615 [inline]
vfs_symlink+0x3eb/0x660 fs/namei.c:4599
do_symlinkat+0x263/0x310 fs/namei.c:4641
__do_sys_symlink fs/namei.c:4662 [inline]
__se_sys_symlink fs/namei.c:4660 [inline]
__x64_sys_symlink+0x75/0x90 fs/namei.c:4660
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&dquot->dq_lock){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
wait_on_dquot fs/quota/dquot.c:355 [inline]
dqget+0x5f2/0x1160 fs/quota/dquot.c:971
dquot_transfer+0x531/0x6a0 fs/quota/dquot.c:2153
ext4_setattr+0x80b/0x2900 fs/ext4/inode.c:5368
notify_change+0x6a9/0x1230 fs/attr.c:503
chown_common+0x538/0x670 fs/open.c:793
do_fchownat+0x1ac/0x200 fs/open.c:824
__do_sys_fchownat fs/open.c:839 [inline]
__se_sys_fchownat fs/open.c:836 [inline]
__x64_sys_fchownat+0xbd/0x160 fs/open.c:836
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&ei->xattr_sem){++++}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3161 [inline]
check_prevs_add kernel/locking/lockdep.c:3280 [inline]
validate_chain kernel/locking/lockdep.c:3904 [inline]
__lock_acquire+0x250b/0x3ce0 kernel/locking/lockdep.c:5202
lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5825
down_write+0x93/0x200 kernel/locking/rwsem.c:1577
ext4_write_lock_xattr fs/ext4/xattr.h:154 [inline]
ext4_xattr_set_handle+0x159/0x1420 fs/ext4/xattr.c:2373
__ext4_set_acl+0x366/0x5d0 fs/ext4/acl.c:217
ext4_set_acl+0x3f9/0x5a0 fs/ext4/acl.c:259
set_posix_acl+0x25f/0x320 fs/posix_acl.c:955
vfs_set_acl+0x5ab/0x920 fs/posix_acl.c:1134
do_set_acl+0xd9/0x1a0 fs/posix_acl.c:1279
do_setxattr+0xeb/0x170 fs/xattr.c:626
__do_sys_fsetxattr+0x2e4/0x350 fs/xattr.c:710
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
&ei->xattr_sem --> &journal->j_trans_barrier --> jbd2_handle

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
rlock(jbd2_handle);
lock(&journal->j_trans_barrier);
lock(jbd2_handle);
lock(&ei->xattr_sem);

*** DEADLOCK ***

3 locks held by syz.0.2834/27060:
#0: ffff88807dde2420 (sb_writers#4){.+.+}-{0:0}, at: __do_sys_fsetxattr+0x230/0x350 fs/xattr.c:708
#1: ffff888078f3e708 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:815 [inline]
#1: ffff888078f3e708 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: vfs_set_acl+0x342/0x920 fs/posix_acl.c:1115
#2: ffff88807dde6958 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0xf6c/0x1430 fs/jbd2/transaction.c:448

stack backtrace:
CPU: 0 UID: 0 PID: 27060 Comm: syz.0.2834 Not tainted 6.12.0-rc1-syzkaller-00031-ge32cde8d2bd7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_circular_bug+0x41c/0x610 kernel/locking/lockdep.c:2074
check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2206
check_prev_add kernel/locking/lockdep.c:3161 [inline]
check_prevs_add kernel/locking/lockdep.c:3280 [inline]
validate_chain kernel/locking/lockdep.c:3904 [inline]
__lock_acquire+0x250b/0x3ce0 kernel/locking/lockdep.c:5202
lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5825
down_write+0x93/0x200 kernel/locking/rwsem.c:1577
ext4_write_lock_xattr fs/ext4/xattr.h:154 [inline]
ext4_xattr_set_handle+0x159/0x1420 fs/ext4/xattr.c:2373
__ext4_set_acl+0x366/0x5d0 fs/ext4/acl.c:217
ext4_set_acl+0x3f9/0x5a0 fs/ext4/acl.c:259
set_posix_acl+0x25f/0x320 fs/posix_acl.c:955
vfs_set_acl+0x5ab/0x920 fs/posix_acl.c:1134
do_set_acl+0xd9/0x1a0 fs/posix_acl.c:1279
do_setxattr+0xeb/0x170 fs/xattr.c:626
__do_sys_fsetxattr+0x2e4/0x350 fs/xattr.c:710
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbfbb57dff9
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:00007fbfbc37e038 EFLAGS: 00000246 ORIG_RAX: 00000000000000be
RAX: ffffffffffffffda RBX: 00007fbfbb736130 RCX: 00007fbfbb57dff9
RDX: 0000000020000500 RSI: 0000000020000100 RDI: 0000000000000007
RBP: 00007fbfbb5f0296 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000002c R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fbfbb736130 R15: 00007ffdf99196e8
</TASK>

---
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Next message: James Clark: "Re: [PATCHSET 0/8] perf tools: Do not set attr.exclude_guest by default (v4)"
Previous message: Robin Murphy: "Re: [PATCH] iommu/dma: Potential uninitialized variable in iommu_dma_unmap_sg"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]