[v5.15] Internal error in ext2_ioctl

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c79648372d02 Linux 5.15.189
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=136941a2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=9e47345638b85bd0
dashboard link: https://syzkaller.appspot.com/bug?extid=2baf3824e2dc5b7ef8af
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7ab49562317a/disk-c7964837.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e847ec1e38d3/vmlinux-c7964837.xz
kernel image: https://storage.googleapis.com/syzbot-assets/263158c6371c/Image-c7964837.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2baf38...@syzkaller.appspotmail.com

loop1: detected capacity change from 0 to 512
EXT2-fs (loop1): warning: mounting ext3 filesystem as ext2
Internal error: Oops - BTI: 0000000036000001 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 5311 Comm: syz.1.462 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
pstate: 42400405 (nZcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=jc)
pc : ext2_ioctl+0x42c/0x8dc fs/ext2/ioctl.c:65
lr : sign_extend64 include/linux/bitops.h:183 [inline]
lr : __uaccess_mask_ptr arch/arm64/include/asm/uaccess.h:244 [inline]
lr : ext2_ioctl+0x3f8/0x8dc fs/ext2/ioctl.c:65
sp : ffff80001ff77ce0
x29: ffff80001ff77ce0 x28: ffff0000d3913680 x27: 0000000000000004
x26: 1fffe0001a7226d0 x25: dfff800000000000 x24: dfff800000000000
x23: ffff800008dc8298 x22: 0000000000400140 x21: 0000000000000000
x20: ffff0000de7f18f0 x19: 0000000000000000 x18: 0000000000000000
x17: 0000000000000002 x16: ffff800008dc86c4 x15: 0000000080087601
x14: 0000000000ff0100 x13: 1ffff0000282e06b x12: 0000000000080000
x11: 0000000000000cd6 x10: 1fffe0001bcfe31e x9 : 00000000fffffff2
x8 : 0000000000000000 x7 : ffff800008750ed4 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000001
x2 : 0000000000000008 x1 : 0000000000000001 x0 : 0000000000000000
Call trace:
ext2_ioctl+0x42c/0x8dc fs/ext2/ioctl.c:65
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
Code: 35001e48 2a1f03e9 b9400288 b8000aa8 (93407d20)
---[ end trace 7e8b15b36f22c03a ]---
----------------
Code disassembly (best guess):
0: 35001e48 cbnz w8, 0x3c8
4: 2a1f03e9 mov w9, wzr
8: b9400288 ldr w8, [x20]
c: b8000aa8 sttr w8, [x21]
* 10: 93407d20 sxtw x0, w9 <-- trapping instruction


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: c79648372d02 Linux 5.15.189
git tree: linux-5.15.y

console output: https://syzkaller.appspot.com/x/log.txt?x=136601a2580000

kernel config: https://syzkaller.appspot.com/x/.config?x=9e47345638b85bd0
dashboard link: https://syzkaller.appspot.com/bug?extid=2baf3824e2dc5b7ef8af
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
userspace arch: arm64

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10f88842580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=138871a2580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7ab49562317a/disk-c7964837.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e847ec1e38d3/vmlinux-c7964837.xz
kernel image: https://storage.googleapis.com/syzbot-assets/263158c6371c/Image-c7964837.gz.xz

mounted in repro: https://storage.googleapis.com/syzbot-assets/ba5f68c204bb/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=17fd49a2580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2baf38...@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 512
EXT2-fs (loop0): warning: mounting ext3 filesystem as ext2

Internal error: Oops - BTI: 0000000036000001 [#1] PREEMPT SMP
Modules linked in:

CPU: 0 PID: 4223 Comm: syz.0.17 Not tainted 5.15.189-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
pstate: 42400405 (nZcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=jc)

pc : ext2_ioctl+0x548/0x8dc fs/ext2/ioctl.c:74
lr : ext2_ioctl+0x524/0x8dc fs/ext2/ioctl.c:74
sp : ffff80001fdb7ce0
x29: ffff80001fdb7ce0 x28: ffff0000c0b651c0 x27: 0000000000000004
x26: 1fffe0001816ca38 x25: 0000000000000000 x24: dfff800000000000
x23: 0000000000000000 x22: 0000000000000001 x21: ffff0000cf8c4500
x20: ffff0000ee0f8138 x19: 00000000fffffff2 x18: 0000000000000000
x17: ffff800016d04000 x16: ffff800008dc87e0 x15: ffff8000167e4500
x14: ffff0000c0b65bc0 x13: dfff800000000000 x12: 0000000000ff0100
x11: 0000000000000000 x10: 0000000000000000 x9 : 0000ffffffffffff
x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000
x5 : ffff800016eaa980 x4 : 0000000000000002 x3 : ffff8000082bfb8c
x2 : 0000000000000001 x1 : 0000000000000001 x0 : 0000000000000000
Call trace:
ext2_ioctl+0x548/0x8dc fs/ext2/ioctl.c:74

vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Code: d503229f 2a1f03f3 2a1f03e0 b8400959 (2a1303e1)
---[ end trace 1878e2c8c0714439 ]---

----------------
Code disassembly (best guess):

0: d503229f csdb
4: 2a1f03f3 mov w19, wzr
8: 2a1f03e0 mov w0, wzr
c: b8400959 ldtr w25, [x10]
* 10: 2a1303e1 mov w1, w19 <-- trapping instruction


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