[syzbot] [ext4?] general protection fault in ext4_acquire_dquot

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 14f8db1c0f9a 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=13c79eca280000
kernel config: https://syzkaller.appspot.com/x/.config?x=a837a8ba7e88bb45
dashboard link: https://syzkaller.appspot.com/bug?extid=e633c79ceaecbf479854
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=130464fa280000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13134234280000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ad6ce516eed3/disk-14f8db1c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1f38c2cc7667/vmlinux-14f8db1c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d795115eee39/Image-14f8db1c.gz.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/aa1d3602f38e/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e633c7...@syzkaller.appspotmail.com

Unable to handle kernel paging request at virtual address dfff800000000005
KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
Mem abort info:
ESR = 0x0000000096000006
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x06: level 2 translation fault
Data abort info:
ISV = 0, ISS = 0x00000006
CM = 0, WnR = 0
[dfff800000000005] address between user and kernel address ranges
Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 6080 Comm: syz-executor747 Not tainted 6.3.0-rc7-syzkaller-g14f8db1c0f9a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : ext4_acquire_dquot+0x1d4/0x398 fs/ext4/super.c:6766
lr : dquot_to_inode fs/ext4/super.c:6740 [inline]
lr : ext4_acquire_dquot+0x1ac/0x398 fs/ext4/super.c:6766
sp : ffff80001eb27280
x29: ffff80001eb27280 x28: 1fffe0001c3c01fc x27: ffff800015d705b0
x26: ffff0000dd93c000 x25: ffff0000dd93e000 x24: 1fffe0001c3c021c
x23: dfff800000000000 x22: 0000000000000049 x21: 0000000000000028
x20: 0000000000000000 x19: ffff0000e1e00fc0 x18: ffff0001b426cca8
x17: 0000000000000000 x16: ffff8000089669b0 x15: 0000000000000001
x14: 1ffff00002bae0b0 x13: dfff800000000000 x12: 0000000000000001
x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000
x8 : 0000000000000005 x7 : ffff800008c11f68 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : ffff800012441b4c
x2 : 0000000000000001 x1 : 0000000000000001 x0 : 0000000000000003
Call trace:
ext4_acquire_dquot+0x1d4/0x398 fs/ext4/super.c:6766
dqget+0x844/0xc48 fs/quota/dquot.c:914
__dquot_initialize+0x2cc/0xb54 fs/quota/dquot.c:1492
dquot_initialize fs/quota/dquot.c:1550 [inline]
dquot_file_open+0x90/0xc8 fs/quota/dquot.c:2181
ext4_file_open+0x230/0x590 fs/ext4/file.c:903
do_dentry_open+0x724/0xf90 fs/open.c:920
vfs_open+0x7c/0x90 fs/open.c:1051
do_open fs/namei.c:3560 [inline]
path_openat+0x1f2c/0x27f8 fs/namei.c:3715
do_filp_open+0x1bc/0x3cc fs/namei.c:3742
do_sys_openat2+0x128/0x3d8 fs/open.c:1348
do_sys_open fs/open.c:1364 [inline]
__do_sys_openat fs/open.c:1380 [inline]
__se_sys_openat fs/open.c:1375 [inline]
__arm64_sys_openat+0x1f0/0x240 fs/open.c:1375
__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
Code: 97e8a7df f94002a8 9100a115 d343fea8 (38776908)
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
0: 97e8a7df bl 0xffffffffffa29f7c
4: f94002a8 ldr x8, [x21]
8: 9100a115 add x21, x8, #0x28
c: d343fea8 lsr x8, x21, #3
* 10: 38776908 ldrb w8, [x8, x23] <-- trapping instruction


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[Theodore Ts'o]

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git test

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+e633c7...@syzkaller.appspotmail.com

Tested on:

commit: 8f98020c ext4: bail out of ext4_xattr_ibody_get() fail..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git test
console output: https://syzkaller.appspot.com/x/log.txt?x=10a4adc6280000
kernel config: https://syzkaller.appspot.com/x/.config?x=78aebd4c3d72a22

dashboard link: https://syzkaller.appspot.com/bug?extid=e633c79ceaecbf479854
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64

Note: no patches were applied.
Note: testing is done by a robot and is best-effort only.