Hello,
syzbot found the following issue on:
HEAD commit: 3b29299e5f60 Linux 6.1.22
git tree: linux-6.1.y
console output:
https://syzkaller.appspot.com/x/log.txt?x=16473145c80000
kernel config:
https://syzkaller.appspot.com/x/.config?x=bbb9a1f6f7f5a1d9
dashboard link:
https://syzkaller.appspot.com/bug?extid=87a27427c88da34e9fc7
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/2affbd06cbfd/disk-3b29299e.raw.xz
vmlinux:
https://storage.googleapis.com/syzbot-assets/8b22d1baf827/vmlinux-3b29299e.xz
kernel image:
https://storage.googleapis.com/syzbot-assets/d5e3891c88bf/Image-3b29299e.gz.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by:
syzbot+87a274...@syzkaller.appspotmail.com
EXT4-fs (loop0): warning: mounting fs with errors, running e2fsck is recommended
[EXT4 FS bs=4096, gc=1, bpg=32768, ipg=32, mo=d054e01c, mo2=0002]
======================================================
WARNING: possible circular locking dependency detected
6.1.22-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.0/9742 is trying to acquire lock:
ffff0000d5138460 (sb_writers#3){.+.+}-{0:0}, at: ext4_multi_mount_protect+0x2e0/0x8a4 fs/ext4/mmp.c:349
but task is already holding lock:
ffff0000d51380e0 (&type->s_umount_key#30){++++}-{3:3}, at: vfs_fsconfig_locked fs/fsopen.c:253 [inline]
ffff0000d51380e0 (&type->s_umount_key#30){++++}-{3:3}, at: __do_sys_fsconfig fs/fsopen.c:439 [inline]
ffff0000d51380e0 (&type->s_umount_key#30){++++}-{3:3}, at: __se_sys_fsconfig fs/fsopen.c:314 [inline]
ffff0000d51380e0 (&type->s_umount_key#30){++++}-{3:3}, at: __arm64_sys_fsconfig+0xa14/0xd18 fs/fsopen.c:314
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&type->s_umount_key#30){++++}-{3:3}:
down_read+0x5c/0x78 kernel/locking/rwsem.c:1520
__do_sys_quotactl_fd fs/quota/quota.c:999 [inline]
__se_sys_quotactl_fd fs/quota/quota.c:972 [inline]
__arm64_sys_quotactl_fd+0x30c/0x4a4 fs/quota/quota.c:972
__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+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581
-> #0 (sb_writers#3){.+.+}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3098 [inline]
check_prevs_add kernel/locking/lockdep.c:3217 [inline]
validate_chain kernel/locking/lockdep.c:3832 [inline]
__lock_acquire+0x3338/0x764c kernel/locking/lockdep.c:5056
lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5669
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1832 [inline]
sb_start_write include/linux/fs.h:1907 [inline]
write_mmp_block+0x100/0xb8c fs/ext4/mmp.c:50
ext4_multi_mount_protect+0x2e0/0x8a4 fs/ext4/mmp.c:349
__ext4_remount fs/ext4/super.c:6530 [inline]
ext4_reconfigure+0x218c/0x2934 fs/ext4/super.c:6629
reconfigure_super+0x328/0x738 fs/super.c:957
vfs_fsconfig_locked fs/fsopen.c:254 [inline]
__do_sys_fsconfig fs/fsopen.c:439 [inline]
__se_sys_fsconfig fs/fsopen.c:314 [inline]
__arm64_sys_fsconfig+0xa1c/0xd18 fs/fsopen.c:314
__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+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&type->s_umount_key#30);
lock(sb_writers#3);
lock(&type->s_umount_key#30);
lock(sb_writers#3);
*** DEADLOCK ***
2 locks held by syz-executor.0/9742:
#0: ffff000103db3470 (&fc->uapi_mutex){+.+.}-{3:3}, at: __do_sys_fsconfig fs/fsopen.c:437 [inline]
#0: ffff000103db3470 (&fc->uapi_mutex){+.+.}-{3:3}, at: __se_sys_fsconfig fs/fsopen.c:314 [inline]
#0: ffff000103db3470 (&fc->uapi_mutex){+.+.}-{3:3}, at: __arm64_sys_fsconfig+0x720/0xd18 fs/fsopen.c:314
#1: ffff0000d51380e0 (&type->s_umount_key#30){++++}-{3:3}, at: vfs_fsconfig_locked fs/fsopen.c:253 [inline]
#1: ffff0000d51380e0 (&type->s_umount_key#30){++++}-{3:3}, at: __do_sys_fsconfig fs/fsopen.c:439 [inline]
#1: ffff0000d51380e0 (&type->s_umount_key#30){++++}-{3:3}, at: __se_sys_fsconfig fs/fsopen.c:314 [inline]
#1: ffff0000d51380e0 (&type->s_umount_key#30){++++}-{3:3}, at: __arm64_sys_fsconfig+0xa14/0xd18 fs/fsopen.c:314
stack backtrace:
CPU: 0 PID: 9742 Comm: syz-executor.0 Not tainted 6.1.22-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Call trace:
dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
dump_stack+0x1c/0x5c lib/dump_stack.c:113
print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2056
check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2178
check_prev_add kernel/locking/lockdep.c:3098 [inline]
check_prevs_add kernel/locking/lockdep.c:3217 [inline]
validate_chain kernel/locking/lockdep.c:3832 [inline]
__lock_acquire+0x3338/0x764c kernel/locking/lockdep.c:5056
lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5669
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1832 [inline]
sb_start_write include/linux/fs.h:1907 [inline]
write_mmp_block+0x100/0xb8c fs/ext4/mmp.c:50
ext4_multi_mount_protect+0x2e0/0x8a4 fs/ext4/mmp.c:349
__ext4_remount fs/ext4/super.c:6530 [inline]
ext4_reconfigure+0x218c/0x2934 fs/ext4/super.c:6629
reconfigure_super+0x328/0x738 fs/super.c:957
vfs_fsconfig_locked fs/fsopen.c:254 [inline]
__do_sys_fsconfig fs/fsopen.c:439 [inline]
__se_sys_fsconfig fs/fsopen.c:314 [inline]
__arm64_sys_fsconfig+0xa1c/0xd18 fs/fsopen.c:314
__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+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581
EXT4-fs warning (device loop0): ext4_enable_quotas:6988: Failed to enable quota tracking (type=0, err=-22, ino=3). Please run e2fsck to fix.
---
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