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Message-ID: <0000000000004332130618548876@google.com>
Date: Mon, 13 May 2024 04:53:22 -0700
From: syzbot <syzbot+4247fb9b4517c79e3b57@...kaller.appspotmail.com>
To: adilger.kernel@...ger.ca, linux-ext4@...r.kernel.org,
linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com, tytso@....edu
Subject: [syzbot] [ext4?] possible deadlock in ext4_xattr_set_handle (5)
Hello,
syzbot found the following issue on:
HEAD commit: 45db3ab70092 Merge tag '6.9-rc7-ksmbd-fixes' of git://git...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=144a905c980000
kernel config: https://syzkaller.appspot.com/x/.config?x=a450595960709c8
dashboard link: https://syzkaller.appspot.com/bug?extid=4247fb9b4517c79e3b57
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: i386
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-45db3ab7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c94d1aa6cd96/vmlinux-45db3ab7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f9daddfda2f1/bzImage-45db3ab7.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4247fb9b4517c79e3b57@...kaller.appspotmail.com
EXT4-fs (loop3): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
======================================================
WARNING: possible circular locking dependency detected
6.9.0-rc7-syzkaller-00056-g45db3ab70092 #0 Not tainted
------------------------------------------------------
syz-executor.3/30481 is trying to acquire lock:
ffffffff8d937180 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:312 [inline]
ffffffff8d937180 (fs_reclaim){+.+.}-{0:0}, at: slab_pre_alloc_hook mm/slub.c:3752 [inline]
ffffffff8d937180 (fs_reclaim){+.+.}-{0:0}, at: slab_alloc_node mm/slub.c:3833 [inline]
ffffffff8d937180 (fs_reclaim){+.+.}-{0:0}, at: __do_kmalloc_node mm/slub.c:3971 [inline]
ffffffff8d937180 (fs_reclaim){+.+.}-{0:0}, at: __kmalloc_node+0xbb/0x480 mm/slub.c:3979
but task is already holding lock:
ffff88802a241ec8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline]
ffff88802a241ec8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_xattr_set_handle+0x156/0x16d0 fs/ext4/xattr.c:2358
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (&ei->xattr_sem){++++}-{3:3}:
down_write+0x3a/0x50 kernel/locking/rwsem.c:1579
ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline]
ext4_xattr_set_handle+0x156/0x16d0 fs/ext4/xattr.c:2358
ext4_xattr_set+0x149/0x380 fs/ext4/xattr.c:2545
__vfs_setxattr+0x173/0x1e0 fs/xattr.c:200
__vfs_setxattr_noperm+0x127/0x5e0 fs/xattr.c:234
__vfs_setxattr_locked+0x182/0x260 fs/xattr.c:295
vfs_setxattr+0x146/0x350 fs/xattr.c:321
do_setxattr+0x146/0x170 fs/xattr.c:629
setxattr+0x15d/0x180 fs/xattr.c:652
path_setxattr+0x179/0x1e0 fs/xattr.c:671
__do_sys_lsetxattr fs/xattr.c:694 [inline]
__se_sys_lsetxattr fs/xattr.c:690 [inline]
__ia32_sys_lsetxattr+0xbd/0x160 fs/xattr.c:690
do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
__do_fast_syscall_32+0x75/0x120 arch/x86/entry/common.c:386
do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
-> #2 (jbd2_handle){++++}-{0:0}:
start_this_handle+0x1101/0x15e0 fs/jbd2/transaction.c:463
jbd2__journal_start+0x394/0x6a0 fs/jbd2/transaction.c:520
__ext4_journal_start_sb+0x358/0x660 fs/ext4/ext4_jbd2.c:112
ext4_sample_last_mounted fs/ext4/file.c:837 [inline]
ext4_file_open+0x636/0xc80 fs/ext4/file.c:866
do_dentry_open+0x8da/0x18c0 fs/open.c:955
do_open fs/namei.c:3642 [inline]
path_openat+0x1dfb/0x2990 fs/namei.c:3799
do_filp_open+0x1dc/0x430 fs/namei.c:3826
do_sys_openat2+0x17a/0x1e0 fs/open.c:1406
do_sys_open fs/open.c:1421 [inline]
__do_sys_openat fs/open.c:1437 [inline]
__se_sys_openat fs/open.c:1432 [inline]
__x64_sys_openat+0x175/0x210 fs/open.c:1432
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (sb_internal){.+.+}-{0:0}:
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1664 [inline]
sb_start_intwrite include/linux/fs.h:1847 [inline]
ext4_evict_inode+0xd7b/0x17d0 fs/ext4/inode.c:212
evict+0x2ed/0x6c0 fs/inode.c:667
iput_final fs/inode.c:1741 [inline]
iput.part.0+0x5a8/0x7f0 fs/inode.c:1767
iput+0x5c/0x80 fs/inode.c:1757
dentry_unlink_inode+0x295/0x440 fs/dcache.c:400
__dentry_kill+0x1d0/0x600 fs/dcache.c:603
shrink_kill fs/dcache.c:1048 [inline]
shrink_dentry_list+0x140/0x5d0 fs/dcache.c:1075
prune_dcache_sb+0xeb/0x150 fs/dcache.c:1156
super_cache_scan+0x32a/0x550 fs/super.c:221
do_shrink_slab+0x44f/0x11c0 mm/shrinker.c:435
shrink_slab_memcg mm/shrinker.c:548 [inline]
shrink_slab+0xa87/0x1310 mm/shrinker.c:626
shrink_one+0x493/0x7c0 mm/vmscan.c:4774
shrink_many mm/vmscan.c:4835 [inline]
lru_gen_shrink_node+0x89f/0x1750 mm/vmscan.c:4935
shrink_node mm/vmscan.c:5894 [inline]
kswapd_shrink_node mm/vmscan.c:6704 [inline]
balance_pgdat+0x10d1/0x1a10 mm/vmscan.c:6895
kswapd+0x5ea/0xbf0 mm/vmscan.c:7164
kthread+0x2c1/0x3a0 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
-> #0 (fs_reclaim){+.+.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain kernel/locking/lockdep.c:3869 [inline]
__lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719
__fs_reclaim_acquire mm/page_alloc.c:3698 [inline]
fs_reclaim_acquire+0x102/0x160 mm/page_alloc.c:3712
might_alloc include/linux/sched/mm.h:312 [inline]
slab_pre_alloc_hook mm/slub.c:3752 [inline]
slab_alloc_node mm/slub.c:3833 [inline]
__do_kmalloc_node mm/slub.c:3971 [inline]
__kmalloc_node+0xbb/0x480 mm/slub.c:3979
kmalloc_node include/linux/slab.h:648 [inline]
kvmalloc_node+0x9d/0x1a0 mm/util.c:634
kvmalloc include/linux/slab.h:766 [inline]
ext4_xattr_inode_cache_find fs/ext4/xattr.c:1535 [inline]
ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1581 [inline]
ext4_xattr_set_entry+0xdc3/0x3b20 fs/ext4/xattr.c:1718
ext4_xattr_block_set+0xd07/0x3080 fs/ext4/xattr.c:2037
ext4_xattr_set_handle+0xf24/0x16d0 fs/ext4/xattr.c:2443
ext4_xattr_set+0x149/0x380 fs/ext4/xattr.c:2545
__vfs_setxattr+0x173/0x1e0 fs/xattr.c:200
__vfs_setxattr_noperm+0x127/0x5e0 fs/xattr.c:234
__vfs_setxattr_locked+0x182/0x260 fs/xattr.c:295
vfs_setxattr+0x146/0x350 fs/xattr.c:321
do_setxattr+0x146/0x170 fs/xattr.c:629
setxattr+0x15d/0x180 fs/xattr.c:652
path_setxattr+0x179/0x1e0 fs/xattr.c:671
__do_sys_setxattr fs/xattr.c:687 [inline]
__se_sys_setxattr fs/xattr.c:683 [inline]
__ia32_sys_setxattr+0xc0/0x160 fs/xattr.c:683
do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
__do_fast_syscall_32+0x75/0x120 arch/x86/entry/common.c:386
do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
other info that might help us debug this:
Chain exists of:
fs_reclaim --> jbd2_handle --> &ei->xattr_sem
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&ei->xattr_sem);
lock(jbd2_handle);
lock(&ei->xattr_sem);
lock(fs_reclaim);
*** DEADLOCK ***
3 locks held by syz-executor.3/30481:
#0: ffff888076954420 (sb_writers#4){.+.+}-{0:0}, at: path_setxattr+0xc3/0x1e0 fs/xattr.c:669
#1: ffff88802a242200 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:795 [inline]
#1: ffff88802a242200 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: vfs_setxattr+0x123/0x350 fs/xattr.c:320
#2: ffff88802a241ec8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline]
#2: ffff88802a241ec8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_xattr_set_handle+0x156/0x16d0 fs/ext4/xattr.c:2358
stack backtrace:
CPU: 0 PID: 30481 Comm: syz-executor.3 Not tainted 6.9.0-rc7-syzkaller-00056-g45db3ab70092 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2187
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain kernel/locking/lockdep.c:3869 [inline]
__lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719
__fs_reclaim_acquire mm/page_alloc.c:3698 [inline]
fs_reclaim_acquire+0x102/0x160 mm/page_alloc.c:3712
might_alloc include/linux/sched/mm.h:312 [inline]
slab_pre_alloc_hook mm/slub.c:3752 [inline]
slab_alloc_node mm/slub.c:3833 [inline]
__do_kmalloc_node mm/slub.c:3971 [inline]
__kmalloc_node+0xbb/0x480 mm/slub.c:3979
kmalloc_node include/linux/slab.h:648 [inline]
kvmalloc_node+0x9d/0x1a0 mm/util.c:634
kvmalloc include/linux/slab.h:766 [inline]
ext4_xattr_inode_cache_find fs/ext4/xattr.c:1535 [inline]
ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1581 [inline]
ext4_xattr_set_entry+0xdc3/0x3b20 fs/ext4/xattr.c:1718
ext4_xattr_block_set+0xd07/0x3080 fs/ext4/xattr.c:2037
ext4_xattr_set_handle+0xf24/0x16d0 fs/ext4/xattr.c:2443
ext4_xattr_set+0x149/0x380 fs/ext4/xattr.c:2545
__vfs_setxattr+0x173/0x1e0 fs/xattr.c:200
__vfs_setxattr_noperm+0x127/0x5e0 fs/xattr.c:234
__vfs_setxattr_locked+0x182/0x260 fs/xattr.c:295
vfs_setxattr+0x146/0x350 fs/xattr.c:321
do_setxattr+0x146/0x170 fs/xattr.c:629
setxattr+0x15d/0x180 fs/xattr.c:652
path_setxattr+0x179/0x1e0 fs/xattr.c:671
__do_sys_setxattr fs/xattr.c:687 [inline]
__se_sys_setxattr fs/xattr.c:683 [inline]
__ia32_sys_setxattr+0xc0/0x160 fs/xattr.c:683
do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
__do_fast_syscall_32+0x75/0x120 arch/x86/entry/common.c:386
do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf72c6579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f5eb85ac EFLAGS: 00000292 ORIG_RAX: 00000000000000e2
RAX: ffffffffffffffda RBX: 0000000020000200 RCX: 00000000200001c0
RDX: 0000000020001400 RSI: 0000000000000835 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
----------------
Code disassembly (best guess), 2 bytes skipped:
0: 10 06 adc %al,(%rsi)
2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi
6: 10 07 adc %al,(%rdi)
8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi
c: 10 08 adc %cl,(%rax)
e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi
1e: 00 51 52 add %dl,0x52(%rcx)
21: 55 push %rbp
22: 89 e5 mov %esp,%ebp
24: 0f 34 sysenter
26: cd 80 int $0x80
* 28: 5d pop %rbp <-- trapping instruction
29: 5a pop %rdx
2a: 59 pop %rcx
2b: c3 ret
2c: 90 nop
2d: 90 nop
2e: 90 nop
2f: 90 nop
30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi
37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi
---
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@...glegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
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