[syzbot] [reiserfs?] possible deadlock in vfs_setxattr (2)

From: syzbot
Date: Tue May 30 2023 - 13:21:04 EST

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Hello,

syzbot found the following issue on:

HEAD commit: eb0f1697d729 Merge branch 'for-next/core', remote-tracking..
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=1545e64d280000
kernel config: https://syzkaller.appspot.com/x/.config?x=8860074b9a9d6c45
dashboard link: https://syzkaller.appspot.com/bug?extid=c98692bac73aedb459c3
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/034232da7cff/disk-eb0f1697.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b11411bec33e/vmlinux-eb0f1697.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a53c52e170dd/Image-eb0f1697.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c98692bac73aedb459c3@xxxxxxxxxxxxxxxxxxxxxxxxx

reiserfs: enabling write barrier flush mode
REISERFS (device loop5): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
6.4.0-rc3-syzkaller-geb0f1697d729 #0 Not tainted
------------------------------------------------------
syz-executor.5/11246 is trying to acquire lock:
ffff0000e040a400 (&type->i_mutex_dir_key#10){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:775 [inline]
ffff0000e040a400 (&type->i_mutex_dir_key#10){+.+.}-{3:3}, at: vfs_setxattr+0x17c/0x344 fs/xattr.c:321

but task is already holding lock:
ffff000113b8a460 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write_file+0x64/0x1e8 fs/namespace.c:438

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #2 (sb_writers#12){.+.+}-{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+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:193
el0_svc+0x4c/0x15c arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
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+0x15b4/0x2028 fs/reiserfs/super.c:2192
mount_bdev+0x26c/0x368 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/0x8c8 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+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:193
el0_svc+0x4c/0x15c arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591

-> #0 (&type->i_mutex_dir_key#10){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3108 [inline]
check_prevs_add kernel/locking/lockdep.c:3227 [inline]
validate_chain kernel/locking/lockdep.c:3842 [inline]
__lock_acquire+0x3310/0x75f0 kernel/locking/lockdep.c:5074
lock_acquire+0x23c/0x71c kernel/locking/lockdep.c:5691
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
__do_sys_fsetxattr fs/xattr.c:709 [inline]
__se_sys_fsetxattr fs/xattr.c:698 [inline]
__arm64_sys_fsetxattr+0x1a8/0x224 fs/xattr.c:698
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:193
el0_svc+0x4c/0x15c arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
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#10 --> &sbi->lock --> sb_writers#12

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
rlock(sb_writers#12);
lock(&sbi->lock);
lock(sb_writers#12);
lock(&type->i_mutex_dir_key#10);

*** DEADLOCK ***

1 lock held by syz-executor.5/11246:
#0: ffff000113b8a460 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write_file+0x64/0x1e8 fs/namespace.c:438

stack backtrace:
CPU: 0 PID: 11246 Comm: syz-executor.5 Not tainted 6.4.0-rc3-syzkaller-geb0f1697d729 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023
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:3108 [inline]
check_prevs_add kernel/locking/lockdep.c:3227 [inline]
validate_chain kernel/locking/lockdep.c:3842 [inline]
__lock_acquire+0x3310/0x75f0 kernel/locking/lockdep.c:5074
lock_acquire+0x23c/0x71c kernel/locking/lockdep.c:5691
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
__do_sys_fsetxattr fs/xattr.c:709 [inline]
__se_sys_fsetxattr fs/xattr.c:698 [inline]
__arm64_sys_fsetxattr+0x1a8/0x224 fs/xattr.c:698
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:193
el0_svc+0x4c/0x15c arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591

---
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Next message: Josh Poimboeuf: "[PATCH 00/22] objtool: Reduce memory usage with CONFIG_DEBUG_INFO"
Previous message: Dave Hansen: "Re: [PATCH v2] x86/msr: Allow unprivileged read access to some MSRs"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]