[v5.15] Internal error in sys_prctl

[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=16643434580000
kernel config: https://syzkaller.appspot.com/x/.config?x=9e47345638b85bd0
dashboard link: https://syzkaller.appspot.com/bug?extid=6abef4479e4b890d53d8
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+6abef4...@syzkaller.appspotmail.com

Internal error: Oops - BTI: 0000000036000001 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 4408 Comm: syz.0.62 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 : __do_sys_prctl kernel/sys.c:2319 [inline]
pc : __se_sys_prctl kernel/sys.c:2298 [inline]
pc : __arm64_sys_prctl+0xbe0/0xf14 kernel/sys.c:2298
lr : sign_extend64 include/linux/bitops.h:183 [inline]
lr : __uaccess_mask_ptr arch/arm64/include/asm/uaccess.h:244 [inline]
lr : __do_sys_prctl kernel/sys.c:2319 [inline]
lr : __se_sys_prctl kernel/sys.c:2298 [inline]
lr : __arm64_sys_prctl+0xbac/0xf14 kernel/sys.c:2298
sp : ffff800021757cc0
x29: ffff800021757d20 x28: ffff0000d3543680 x27: ffff800021757cc0
x26: 1ffff000042eaf98 x25: dfff800000000000 x24: 00000000ffffffda
x23: 0000000000000000 x22: 0000000000000000 x21: 0000000000000000
x20: ffff0000d3543ba0 x19: 0000000000000000 x18: 0000000000000000
x17: 0000000000000002 x16: ffff8000081dfaa0 x15: 000000000000003d
x14: 0000000000ff0100 x13: 1ffff0000282e06b x12: 0000000000080000
x11: 000000000000012e x10: 1fffe0001a6a8774 x9 : 00000000fffffff2
x8 : 0000000000000000 x7 : ffff800008750ed4 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000001
x2 : 0000000000000008 x1 : 0000000000000001 x0 : 0000000000000000
Call trace:
__do_sys_prctl kernel/sys.c:2319 [inline]
__se_sys_prctl kernel/sys.c:2298 [inline]
__arm64_sys_prctl+0xbe0/0xf14 kernel/sys.c:2298
__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: 35001248 2a1f03e9 b9400288 b8000aa8 (93407d20)
---[ end trace f7f6838d4cf0e40c ]---
----------------
Code disassembly (best guess):
0: 35001248 cbnz w8, 0x248
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=15bd71a2580000

kernel config: https://syzkaller.appspot.com/x/.config?x=9e47345638b85bd0
dashboard link: https://syzkaller.appspot.com/bug?extid=6abef4479e4b890d53d8
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=124629a2580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=119ec9a2580000

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+6abef4...@syzkaller.appspotmail.com

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

CPU: 0 PID: 4250 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 : __do_sys_prctl kernel/sys.c:2319 [inline]
pc : __se_sys_prctl kernel/sys.c:2298 [inline]
pc : __arm64_sys_prctl+0xbe0/0xf14 kernel/sys.c:2298
lr : sign_extend64 include/linux/bitops.h:183 [inline]
lr : __uaccess_mask_ptr arch/arm64/include/asm/uaccess.h:244 [inline]
lr : __do_sys_prctl kernel/sys.c:2319 [inline]
lr : __se_sys_prctl kernel/sys.c:2298 [inline]
lr : __arm64_sys_prctl+0xbac/0xf14 kernel/sys.c:2298

sp : ffff800020be7cc0
x29: ffff800020be7d20 x28: ffff0000d7edb680 x27: ffff800020be7cc0
x26: 1ffff0000417cf98 x25: dfff800000000000 x24: 00000000ffffffda

x23: 0000000000000000 x22: 0000000000000000 x21: 0000000000000000

x20: ffff0000d7edbba0 x19: 0000000000000000 x18: 0000000000000000
x17: 0000000000000000 x16: ffff8000081dfaa0 x15: 000000000000003d
x14: 0000000000ff0100 x13: 1ffff0000282e06b x12: 0000000000ff0100
x11: 0000000000000000 x10: 1fffe0001afdb774 x9 : 00000000fffffff2

x8 : 0000000000000000 x7 : ffff800008750ed4 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000001
x2 : 0000000000000008 x1 : 0000000000000001 x0 : 0000000000000000
Call trace:
__do_sys_prctl kernel/sys.c:2319 [inline]
__se_sys_prctl kernel/sys.c:2298 [inline]
__arm64_sys_prctl+0xbe0/0xf14 kernel/sys.c:2298
__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: 35001248 2a1f03e9 b9400288 b8000aa8 (93407d20)

---[ end trace 23b74ef4d7a18028 ]---

----------------
Code disassembly (best guess):
0: 35001248 cbnz w8, 0x248
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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