[v5.15] Internal error in sys_mount

[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=13b91434580000
kernel config: https://syzkaller.appspot.com/x/.config?x=9e47345638b85bd0
dashboard link: https://syzkaller.appspot.com/bug?extid=f0746890032313ff22e4
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+f07468...@syzkaller.appspotmail.com

cgroup: Unknown subsys name 'net'
Internal error: Oops - BTI: 0000000036000001 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 4033 Comm: syz-executor 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 : copy_mount_options fs/namespace.c:3235 [inline]
pc : __do_sys_mount fs/namespace.c:3560 [inline]
pc : __se_sys_mount fs/namespace.c:3542 [inline]
pc : __arm64_sys_mount+0x2f8/0x5e4 fs/namespace.c:3542
lr : copy_mount_options fs/namespace.c:3235 [inline]
lr : __do_sys_mount fs/namespace.c:3560 [inline]
lr : __se_sys_mount fs/namespace.c:3542 [inline]
lr : __arm64_sys_mount+0x2d4/0x5e4 fs/namespace.c:3542
sp : ffff80001f727c80
x29: ffff80001f727d20 x28: 00000000fffffff2 x27: 0000fffff5b78000
x26: ffff0000daf83680 x25: 0000000000000000 x24: 0000fffff5b771c1
x23: ffff0000daccc000 x22: 0000000000000e3f x21: dfff800000000000
x20: 00000000fffffe3f x19: 0000000000000000 x18: 0000000000000000
x17: 0000000000000000 x16: ffff8000089650ac x15: 0000fffff5b771c1
x14: 2e302e3832312e30 x13: 1ffff0000282e06b x12: 0000000000ff0100
x11: 0000000000000000 x10: 0000ffffffffffff x9 : 0000fffff5b78000
x8 : 0000fffff5b78000 x7 : ffff800008750ed4 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000001
x2 : 0000000000000008 x1 : 0000000000000001 x0 : 0000000000000000
Call trace:
copy_mount_options fs/namespace.c:3235 [inline]
__do_sys_mount fs/namespace.c:3560 [inline]
__se_sys_mount fs/namespace.c:3542 [inline]
__arm64_sys_mount+0x2f8/0x5e4 fs/namespace.c:3542
__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 2a1903fc 2a1903e0 38400933 (2a1c03e1)
---[ end trace 2f9fd14f7c452e96 ]---
----------------
Code disassembly (best guess):
0: d503229f csdb
4: 2a1903fc mov w28, w25
8: 2a1903e0 mov w0, w25
c: 38400933 ldtrb w19, [x9]
* 10: 2a1c03e1 mov w1, w28 <-- 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=17fcf2f0580000

kernel config: https://syzkaller.appspot.com/x/.config?x=9e47345638b85bd0
dashboard link: https://syzkaller.appspot.com/bug?extid=f0746890032313ff22e4
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=13fd3434580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12d449a2580000

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+f07468...@syzkaller.appspotmail.com

cgroup: Unknown subsys name 'net'
Internal error: Oops - BTI: 0000000036000001 [#1] PREEMPT SMP
Modules linked in:

CPU: 1 PID: 4049 Comm: syz-executor 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 : copy_mount_options fs/namespace.c:3235 [inline]
pc : __do_sys_mount fs/namespace.c:3560 [inline]
pc : __se_sys_mount fs/namespace.c:3542 [inline]
pc : __arm64_sys_mount+0x2f8/0x5e4 fs/namespace.c:3542
lr : copy_mount_options fs/namespace.c:3235 [inline]
lr : __do_sys_mount fs/namespace.c:3560 [inline]
lr : __se_sys_mount fs/namespace.c:3542 [inline]
lr : __arm64_sys_mount+0x2d4/0x5e4 fs/namespace.c:3542

sp : ffff80001f5a7c80
x29: ffff80001f5a7d20 x28: 00000000fffffff2 x27: 0000ffffd52e6000
x26: ffff0000d12251c0 x25: 0000000000000000 x24: 0000ffffd52e5251
x23: ffff0000c2dd4000 x22: 0000000000000daf x21: dfff800000000000
x20: 00000000fffffdaf x19: 0000000000000000 x18: 0000000000000000
x17: 0000000000000000 x16: ffff8000089650ac x15: 0000ffffd52e5251
x14: 2e3832312e303120 x13: 1ffff0000282e06b x12: 0000000000ff0100
x11: 0000000000000000 x10: 0000ffffffffffff x9 : 0000ffffd52e6000
x8 : 0000ffffd52e6000 x7 : ffff800008750ed4 x6 : 0000000000000000

x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000001
x2 : 0000000000000008 x1 : 0000000000000001 x0 : 0000000000000000
Call trace:
copy_mount_options fs/namespace.c:3235 [inline]
__do_sys_mount fs/namespace.c:3560 [inline]
__se_sys_mount fs/namespace.c:3542 [inline]
__arm64_sys_mount+0x2f8/0x5e4 fs/namespace.c:3542
__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 2a1903fc 2a1903e0 38400933 (2a1c03e1)

---[ end trace 5864d0859216d74c ]---

----------------
Code disassembly (best guess):
0: d503229f csdb
4: 2a1903fc mov w28, w25
8: 2a1903e0 mov w0, w25
c: 38400933 ldtrb w19, [x9]
* 10: 2a1c03e1 mov w1, w28 <-- trapping instruction


---

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