[syzbot] [ocfs2?] possible deadlock in ocfs2_setattr

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 521b1e7f4cf0 Merge tag 'cxl-fixes-6.11-rc5' of git://git.k..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=175453cb980000
kernel config: https://syzkaller.appspot.com/x/.config?x=df2f0ed7e30a639d
dashboard link: https://syzkaller.appspot.com/bug?extid=d78497256d53041ee229
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=1395e991980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13659d6b980000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-521b1e7f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fc256e887f7f/vmlinux-521b1e7f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0ecca3914e31/bzImage-521b1e7f.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/4ad0fdc1f43e/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d78497...@syzkaller.appspotmail.com

JBD2: Ignoring recovery information on journal
ocfs2: Mounting device (7,0) on (node local, slot 0) with writeback data mode.
======================================================
WARNING: possible circular locking dependency detected
6.11.0-rc4-syzkaller-00011-g521b1e7f4cf0 #0 Not tainted
------------------------------------------------------
syz-executor408/5110 is trying to acquire lock:
ffff888037bf6610 (sb_internal#2){.+.+}-{0:0}, at: ocfs2_setattr+0xcb1/0x1f50 fs/ocfs2/file.c:1259

but task is already holding lock:
ffff88803c2bcda0 (&oi->ip_alloc_sem){+.+.}-{3:3}, at: ocfs2_setattr+0xc9f/0x1f50 fs/ocfs2/file.c:1258

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (&oi->ip_alloc_sem){+.+.}-{3:3}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
down_write+0x99/0x220 kernel/locking/rwsem.c:1579
ocfs2_try_remove_refcount_tree+0xb6/0x330 fs/ocfs2/refcounttree.c:931
ocfs2_xattr_set+0xa4f/0x1930 fs/ocfs2/xattr.c:3670
ocfs2_set_acl+0x4cb/0x580 fs/ocfs2/acl.c:254
ocfs2_iop_set_acl+0x24a/0x3c0 fs/ocfs2/acl.c:286
set_posix_acl fs/posix_acl.c:955 [inline]
vfs_set_acl+0x7fd/0xa60 fs/posix_acl.c:1134
do_setxattr fs/xattr.c:626 [inline]
path_setxattr+0x3bd/0x4d0 fs/xattr.c:658
__do_sys_setxattr fs/xattr.c:676 [inline]
__se_sys_setxattr fs/xattr.c:672 [inline]
__x64_sys_setxattr+0xbb/0xd0 fs/xattr.c:672
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #3 (&oi->ip_xattr_sem){++++}-{3:3}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
down_read+0xb1/0xa40 kernel/locking/rwsem.c:1526
ocfs2_init_acl+0x397/0x930 fs/ocfs2/acl.c:366
ocfs2_mknod+0x1c05/0x2b40 fs/ocfs2/namei.c:408
ocfs2_create+0x1ab/0x480 fs/ocfs2/namei.c:672
vfs_create+0x23c/0x3d0 fs/namei.c:3280
do_mknodat+0x447/0x5b0 fs/namei.c:4138
__do_sys_mknodat fs/namei.c:4166 [inline]
__se_sys_mknodat fs/namei.c:4163 [inline]
__x64_sys_mknodat+0xa7/0xc0 fs/namei.c:4163
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (jbd2_handle){.+.+}-{0:0}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
start_this_handle+0x1eb4/0x2110 fs/jbd2/transaction.c:448
jbd2__journal_start+0x2da/0x5d0 fs/jbd2/transaction.c:505
jbd2_journal_start+0x29/0x40 fs/jbd2/transaction.c:544
ocfs2_start_trans+0x3c9/0x700 fs/ocfs2/journal.c:352
ocfs2_mknod+0x150c/0x2b40 fs/ocfs2/namei.c:359
ocfs2_create+0x1ab/0x480 fs/ocfs2/namei.c:672
vfs_create+0x23c/0x3d0 fs/namei.c:3280
do_mknodat+0x447/0x5b0 fs/namei.c:4138
__do_sys_mknodat fs/namei.c:4166 [inline]
__se_sys_mknodat fs/namei.c:4163 [inline]
__x64_sys_mknodat+0xa7/0xc0 fs/namei.c:4163
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&journal->j_trans_barrier){.+.+}-{3:3}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
down_read+0xb1/0xa40 kernel/locking/rwsem.c:1526
ocfs2_start_trans+0x3be/0x700 fs/ocfs2/journal.c:350
ocfs2_mknod+0x150c/0x2b40 fs/ocfs2/namei.c:359
ocfs2_create+0x1ab/0x480 fs/ocfs2/namei.c:672
vfs_create+0x23c/0x3d0 fs/namei.c:3280
do_mknodat+0x447/0x5b0 fs/namei.c:4138
__do_sys_mknodat fs/namei.c:4166 [inline]
__se_sys_mknodat fs/namei.c:4163 [inline]
__x64_sys_mknodat+0xa7/0xc0 fs/namei.c:4163
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (sb_internal#2){.+.+}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3133 [inline]
check_prevs_add kernel/locking/lockdep.c:3252 [inline]
validate_chain+0x18e0/0x5900 kernel/locking/lockdep.c:3868
__lock_acquire+0x137a/0x2040 kernel/locking/lockdep.c:5142
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1675 [inline]
sb_start_intwrite include/linux/fs.h:1858 [inline]
ocfs2_start_trans+0x2b9/0x700 fs/ocfs2/journal.c:348
ocfs2_setattr+0xcb1/0x1f50 fs/ocfs2/file.c:1259
notify_change+0xb9d/0xe70 fs/attr.c:495
chmod_common+0x2ab/0x4c0 fs/open.c:654
do_fchmodat fs/open.c:702 [inline]
__do_sys_fchmodat fs/open.c:721 [inline]
__se_sys_fchmodat fs/open.c:718 [inline]
__x64_sys_fchmodat+0x11d/0x1c0 fs/open.c:718
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
sb_internal#2 --> &oi->ip_xattr_sem --> &oi->ip_alloc_sem

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&oi->ip_alloc_sem);
lock(&oi->ip_xattr_sem);
lock(&oi->ip_alloc_sem);
rlock(sb_internal#2);

*** DEADLOCK ***

3 locks held by syz-executor408/5110:
#0: ffff888037bf6420 (sb_writers#9){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:515
#1: ffff88803c2bd100 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:799 [inline]
#1: ffff88803c2bd100 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: chmod_common+0x1bb/0x4c0 fs/open.c:648
#2: ffff88803c2bcda0 (&oi->ip_alloc_sem){+.+.}-{3:3}, at: ocfs2_setattr+0xc9f/0x1f50 fs/ocfs2/file.c:1258

stack backtrace:
CPU: 0 UID: 0 PID: 5110 Comm: syz-executor408 Not tainted 6.11.0-rc4-syzkaller-00011-g521b1e7f4cf0 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:93 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2186
check_prev_add kernel/locking/lockdep.c:3133 [inline]
check_prevs_add kernel/locking/lockdep.c:3252 [inline]
validate_chain+0x18e0/0x5900 kernel/locking/lockdep.c:3868
__lock_acquire+0x137a/0x2040 kernel/locking/lockdep.c:5142
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1675 [inline]
sb_start_intwrite include/linux/fs.h:1858 [inline]
ocfs2_start_trans+0x2b9/0x700 fs/ocfs2/journal.c:348
ocfs2_setattr+0xcb1/0x1f50 fs/ocfs2/file.c:1259
notify_change+0xb9d/0xe70 fs/attr.c:495
chmod_common+0x2ab/0x4c0 fs/open.c:654
do_fchmodat fs/open.c:702 [inline]
__do_sys_fchmodat fs/open.c:721 [inline]
__se_sys_fchmodat fs/open.c:718 [inline]
__x64_sys_fchmodat+0x11d/0x1c0 fs/open.c:718
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff865822659
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 17 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:00007fffa6552a68 EFLAGS: 00000246 ORIG_RAX: 000000000000010c
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff865822659
RDX: 00000000000001ff RSI: 0000000020000440 RDI: 00000000ffffff9c
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007fffa6552aa0
R10: 00007fffa6552a70 R11: 0000000000000246 R12: 00007fffa6552aa0
R13: 00007fffa6552d28 R14: 431bde82d7b634db R15: 00007ff86586b03b
</TASK>


---
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If the report is already addressed, let syzbot know by replying with:
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[Edward Adam Davis]

use trylock to replace

#syz test: upstream 521b1e7f4cf0

diff --git a/fs/ocfs2/acl.c b/fs/ocfs2/acl.c
index 62464d194da3..f60e3178fe74 100644
--- a/fs/ocfs2/acl.c
+++ b/fs/ocfs2/acl.c
@@ -363,7 +363,8 @@ int ocfs2_init_acl(handle_t *handle,

if (!S_ISLNK(inode->i_mode)) {
if (osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL) {
- down_read(&OCFS2_I(dir)->ip_xattr_sem);
+ if (!down_read_trylock(&OCFS2_I(dir)->ip_xattr_sem))
+ return -EBUSY;
acl = ocfs2_get_acl_nolock(dir, ACL_TYPE_DEFAULT,
dir_bh);
up_read(&OCFS2_I(dir)->ip_xattr_sem);

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+d78497...@syzkaller.appspotmail.com
Tested-by: syzbot+d78497...@syzkaller.appspotmail.com

Tested on:

commit: 521b1e7f Merge tag 'cxl-fixes-6.11-rc5' of git://git.k..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=143dc36b980000

kernel config: https://syzkaller.appspot.com/x/.config?x=df2f0ed7e30a639d
dashboard link: https://syzkaller.appspot.com/bug?extid=d78497256d53041ee229
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=103a87e5980000

Note: testing is done by a robot and is best-effort only.

[syzbot]

syzbot has bisected this issue to:

commit a3c06ae158dd6fa8336157c31d9234689d068d02
Author: Parav Pandit <pa...@nvidia.com>
Date: Tue Jan 5 10:32:03 2021 +0000

vdpa_sim_net: Add support for user supported devices

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=17fc2640580000
start commit: d12937763990 Merge tag 'for-linus' of git://git.kernel.org..
git tree: upstream
final oops: https://syzkaller.appspot.com/x/report.txt?x=14022640580000
console output: https://syzkaller.appspot.com/x/log.txt?x=10022640580000
kernel config: https://syzkaller.appspot.com/x/.config?x=41330fd2db03893d
dashboard link: https://syzkaller.appspot.com/bug?extid=d78497256d53041ee229
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12d0dc87980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14e19430580000

Reported-by: syzbot+d78497...@syzkaller.appspotmail.com
Fixes: a3c06ae158dd ("vdpa_sim_net: Add support for user supported devices")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

[Jason Wang]

On Tue, Oct 22, 2024 at 11:31 PM syzbot
<syzbot+d78497...@syzkaller.appspotmail.com> wrote:
>
> syzbot has bisected this issue to:
>
> commit a3c06ae158dd6fa8336157c31d9234689d068d02
> Author: Parav Pandit <pa...@nvidia.com>
> Date: Tue Jan 5 10:32:03 2021 +0000
>
> vdpa_sim_net: Add support for user supported devices

This commit seems to be ir-revelant as the changes are limited to
vDPA. It only shows the user vDPA mgmt devices which has nothing to do
with ocfs.

Thanks