Re: [syzbot] [reiserfs?] possible deadlock in vfs_setxattr (2)
From: syzbot
Date: Mon Jul 17 2023 - 17:25:02 EST
syzbot has found a reproducer for the following issue on:
HEAD commit: e40939bbfc68 Merge branch 'for-next/core' into for-kernelci
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=117c0fa2a80000
kernel config: https://syzkaller.appspot.com/x/.config?x=c4a2640e4213bc2f
dashboard link: https://syzkaller.appspot.com/bug?extid=c98692bac73aedb459c3
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=107ec3faa80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15bc5646a80000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9d87aa312c0e/disk-e40939bb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/22a11d32a8b2/vmlinux-e40939bb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0978b5788b52/Image-e40939bb.gz.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/cd09072f381d/mount_0.gz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c98692bac73aedb459c3@xxxxxxxxxxxxxxxxxxxxxxxxx
REISERFS (device loop0): Using tea hash to sort names
REISERFS (device loop0): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
6.4.0-rc7-syzkaller-ge40939bbfc68 #0 Not tainted
------------------------------------------------------
syz-executor558/5970 is trying to acquire lock:
ffff0000e0a782e0 (&type->i_mutex_dir_key#6){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:775 [inline]
ffff0000e0a782e0 (&type->i_mutex_dir_key#6){+.+.}-{3:3}, at: vfs_setxattr+0x17c/0x344 fs/xattr.c:321
but task is already holding lock:
ffff0000c67ac460 (sb_writers#8){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:394
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (sb_writers#8){.+.+}-{0:0}:
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1494 [inline]
sb_start_write+0x60/0x2ec include/linux/fs.h:1569
mnt_want_write_file+0x64/0x1e8 fs/namespace.c:438
reiserfs_ioctl+0x184/0x454 fs/reiserfs/ioctl.c:103
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x244 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:191
el0_svc+0x4c/0x160 arch/arm64/kernel/entry-common.c:647
el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:665
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591
-> #1 (&sbi->lock){+.+.}-{3:3}:
__mutex_lock_common+0x190/0x21a0 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:799
reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
reiserfs_lookup+0x128/0x45c fs/reiserfs/namei.c:364
__lookup_slow+0x250/0x374 fs/namei.c:1690
lookup_one_len+0x178/0x28c fs/namei.c:2742
reiserfs_lookup_privroot+0x8c/0x184 fs/reiserfs/xattr.c:976
reiserfs_fill_super+0x1bc0/0x2028 fs/reiserfs/super.c:2174
mount_bdev+0x274/0x370 fs/super.c:1380
get_super_block+0x44/0x58 fs/reiserfs/super.c:2601
legacy_get_tree+0xd4/0x16c fs/fs_context.c:610
vfs_get_tree+0x90/0x274 fs/super.c:1510
do_new_mount+0x25c/0x8c4 fs/namespace.c:3039
path_mount+0x590/0xe04 fs/namespace.c:3369
do_mount fs/namespace.c:3382 [inline]
__do_sys_mount fs/namespace.c:3591 [inline]
__se_sys_mount fs/namespace.c:3568 [inline]
__arm64_sys_mount+0x45c/0x594 fs/namespace.c:3568
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x244 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:191
el0_svc+0x4c/0x160 arch/arm64/kernel/entry-common.c:647
el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:665
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591
-> #0 (&type->i_mutex_dir_key#6){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3113 [inline]
check_prevs_add kernel/locking/lockdep.c:3232 [inline]
validate_chain kernel/locking/lockdep.c:3847 [inline]
__lock_acquire+0x3308/0x7604 kernel/locking/lockdep.c:5088
lock_acquire+0x23c/0x71c kernel/locking/lockdep.c:5705
down_write+0x50/0xc0 kernel/locking/rwsem.c:1573
inode_lock include/linux/fs.h:775 [inline]
vfs_setxattr+0x17c/0x344 fs/xattr.c:321
do_setxattr fs/xattr.c:630 [inline]
setxattr+0x208/0x29c fs/xattr.c:653
path_setxattr+0x17c/0x258 fs/xattr.c:672
__do_sys_setxattr fs/xattr.c:688 [inline]
__se_sys_setxattr fs/xattr.c:684 [inline]
__arm64_sys_setxattr+0xbc/0xd8 fs/xattr.c:684
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x244 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:191
el0_svc+0x4c/0x160 arch/arm64/kernel/entry-common.c:647
el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:665
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591
other info that might help us debug this:
Chain exists of:
&type->i_mutex_dir_key#6 --> &sbi->lock --> sb_writers#8
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
rlock(sb_writers#8);
lock(&sbi->lock);
lock(sb_writers#8);
lock(&type->i_mutex_dir_key#6);
*** DEADLOCK ***
1 lock held by syz-executor558/5970:
#0: ffff0000c67ac460 (sb_writers#8){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:394
stack backtrace:
CPU: 1 PID: 5970 Comm: syz-executor558 Not tainted 6.4.0-rc7-syzkaller-ge40939bbfc68 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/03/2023
Call trace:
dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:233
show_stack+0x2c/0x44 arch/arm64/kernel/stacktrace.c:240
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106
dump_stack+0x1c/0x28 lib/dump_stack.c:113
print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2066
check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2188
check_prev_add kernel/locking/lockdep.c:3113 [inline]
check_prevs_add kernel/locking/lockdep.c:3232 [inline]
validate_chain kernel/locking/lockdep.c:3847 [inline]
__lock_acquire+0x3308/0x7604 kernel/locking/lockdep.c:5088
lock_acquire+0x23c/0x71c kernel/locking/lockdep.c:5705
down_write+0x50/0xc0 kernel/locking/rwsem.c:1573
inode_lock include/linux/fs.h:775 [inline]
vfs_setxattr+0x17c/0x344 fs/xattr.c:321
do_setxattr fs/xattr.c:630 [inline]
setxattr+0x208/0x29c fs/xattr.c:653
path_setxattr+0x17c/0x258 fs/xattr.c:672
__do_sys_setxattr fs/xattr.c:688 [inline]
__se_sys_setxattr fs/xattr.c:684 [inline]
__arm64_sys_setxattr+0xbc/0xd8 fs/xattr.c:684
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x244 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:191
el0_svc+0x4c/0x160 arch/arm64/kernel/entry-common.c:647
el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:665
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591
---
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