From: syzbot <syzbot+62120febbd1ee3c3c860@syzkaller.appspotmail.com>
To: adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org,
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com,
tytso@mit.edu
Subject: [syzbot] possible deadlock in ext4_xattr_get
Date: Sun, 07 Aug 2022 06:08:25 -0700 [thread overview]
Message-ID: <000000000000fb20b605e5a66457@google.com> (raw)
Hello,
syzbot found the following issue on:
HEAD commit: cb71b93c2dc3 Add linux-next specific files for 20220628
git tree: linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=10bdcf3c080000
kernel config: https://syzkaller.appspot.com/x/.config?x=badbc1adb2d582eb
dashboard link: https://syzkaller.appspot.com/bug?extid=62120febbd1ee3c3c860
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10256c61080000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11f3c832080000
Bisection is inconclusive: the issue happens on the oldest tested release.
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=12420fe2080000
final oops: https://syzkaller.appspot.com/x/report.txt?x=11420fe2080000
console output: https://syzkaller.appspot.com/x/log.txt?x=16420fe2080000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+62120febbd1ee3c3c860@syzkaller.appspotmail.com
loop0: detected capacity change from 0 to 512
EXT4-fs (loop0): mounted filesystem without journal. Quota mode: none.
======================================================
WARNING: possible circular locking dependency detected
5.19.0-rc4-next-20220628-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor246/3601 is trying to acquire lock:
ffff888075af28e8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_xattr_get+0x14e/0xa10 fs/ext4/xattr.c:650
but task is already holding lock:
ffff888075af2c20 (&ea_inode->i_rwsem#9/1){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:761 [inline]
ffff888075af2c20 (&ea_inode->i_rwsem#9/1){+.+.}-{3:3}, at: chown_common+0x364/0x710 fs/open.c:727
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&ea_inode->i_rwsem#9/1){+.+.}-{3:3}:
down_write+0x90/0x150 kernel/locking/rwsem.c:1542
inode_lock include/linux/fs.h:761 [inline]
ext4_xattr_inode_create fs/ext4/xattr.c:1445 [inline]
ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1528 [inline]
ext4_xattr_set_entry+0x2ab3/0x3850 fs/ext4/xattr.c:1656
ext4_xattr_ibody_set+0x78/0x2b0 fs/ext4/xattr.c:2209
ext4_xattr_set_handle+0x964/0x1500 fs/ext4/xattr.c:2366
ext4_xattr_set+0x13a/0x340 fs/ext4/xattr.c:2479
__vfs_setxattr+0x115/0x180 fs/xattr.c:182
__vfs_setxattr_noperm+0x125/0x5f0 fs/xattr.c:216
__vfs_setxattr_locked+0x1cf/0x260 fs/xattr.c:277
vfs_setxattr+0x13f/0x330 fs/xattr.c:303
setxattr+0x146/0x160 fs/xattr.c:611
path_setxattr+0x197/0x1c0 fs/xattr.c:630
__do_sys_setxattr fs/xattr.c:646 [inline]
__se_sys_setxattr fs/xattr.c:642 [inline]
__x64_sys_setxattr+0xc0/0x160 fs/xattr.c:642
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
-> #0 (&ei->xattr_sem){++++}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3095 [inline]
check_prevs_add kernel/locking/lockdep.c:3214 [inline]
validate_chain kernel/locking/lockdep.c:3829 [inline]
__lock_acquire+0x2abe/0x5660 kernel/locking/lockdep.c:5053
lock_acquire kernel/locking/lockdep.c:5665 [inline]
lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5630
down_read+0x98/0x440 kernel/locking/rwsem.c:1489
ext4_xattr_get+0x14e/0xa10 fs/ext4/xattr.c:650
__vfs_getxattr+0xd9/0x140 fs/xattr.c:401
cap_inode_need_killpriv+0x3c/0x60 security/commoncap.c:301
security_inode_need_killpriv+0x40/0x90 security/security.c:1420
notify_change+0x6e7/0x1440 fs/attr.c:351
chown_common+0x61b/0x710 fs/open.c:734
do_fchownat+0x126/0x1e0 fs/open.c:765
__do_sys_fchownat fs/open.c:780 [inline]
__se_sys_fchownat fs/open.c:777 [inline]
__x64_sys_fchownat+0xba/0x150 fs/open.c:777
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&ea_inode->i_rwsem#9/1);
lock(&ei->xattr_sem);
lock(&ea_inode->i_rwsem#9/1);
lock(&ei->xattr_sem);
*** DEADLOCK ***
2 locks held by syz-executor246/3601:
#0: ffff88801d65e460 (sb_writers#4){.+.+}-{0:0}, at: do_fchownat+0x101/0x1e0 fs/open.c:762
#1: ffff888075af2c20 (&ea_inode->i_rwsem#9/1){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:761 [inline]
#1: ffff888075af2c20 (&ea_inode->i_rwsem#9/1){+.+.}-{3:3}, at: chown_common+0x364/0x710 fs/open.c:727
stack backtrace:
CPU: 0 PID: 3601 Comm: syz-executor246 Not tainted 5.19.0-rc4-next-20220628-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3095 [inline]
check_prevs_add kernel/locking/lockdep.c:3214 [inline]
validate_chain kernel/locking/lockdep.c:3829 [inline]
__lock_acquire+0x2abe/0x5660 kernel/locking/lockdep.c:5053
lock_acquire kernel/locking/lockdep.c:5665 [inline]
lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5630
down_read+0x98/0x440 kernel/locking/rwsem.c:1489
ext4_xattr_get+0x14e/0xa10 fs/ext4/xattr.c:650
__vfs_getxattr+0xd9/0x140 fs/xattr.c:401
cap_inode_need_killpriv+0x3c/0x60 security/commoncap.c:301
security_inode_need_killpriv+0x40/0x90 security/security.c:1420
notify_change+0x6e7/0x1440 fs/attr.c:351
chown_common+0x61b/0x710 fs/open.c:734
do_fchownat+0x126/0x1e0 fs/open.c:765
__do_sys_fchownat fs/open.c:780 [inline]
__se_sys_fchownat fs/open.c:777 [inline]
__x64_sys_fchownat+0xba/0x150 fs/open.c:777
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7ff813f7d0e9
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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc815d6a78 EFLAGS: 00000246 ORIG_RAX: 0000000000000104
RAX: ffffffffffffffda RBX:
---
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 syzkaller@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches
next reply other threads:[~2022-08-07 13:08 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-07 13:08 syzbot [this message]
[not found] <20220808111439.2119-1-hdanton@sina.com>
2022-08-08 11:26 ` [syzbot] possible deadlock in ext4_xattr_get syzbot
[not found] <20220808121037.2180-1-hdanton@sina.com>
2022-08-08 12:21 ` syzbot
[not found] <20220808133219.2248-1-hdanton@sina.com>
2022-08-09 1:03 ` syzbot
2022-08-09 1:48 ` Theodore Ts'o
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=000000000000fb20b605e5a66457@google.com \
--to=syzbot+62120febbd1ee3c3c860@syzkaller.appspotmail.com \
--cc=adilger.kernel@dilger.ca \
--cc=linux-ext4@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=syzkaller-bugs@googlegroups.com \
--cc=tytso@mit.edu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.