[v5.15] Internal error in sys_get_robust_list

[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=120d3ea2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=9e47345638b85bd0
dashboard link: https://syzkaller.appspot.com/bug?extid=e7f4a39b04db725cb490
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+e7f4a3...@syzkaller.appspotmail.com

Internal error: Oops - BTI: 0000000036000001 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 5947 Comm: syz.1.811 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_get_robust_list kernel/futex/core.c:3623 [inline]
pc : __se_sys_get_robust_list kernel/futex/core.c:3594 [inline]
pc : __arm64_sys_get_robust_list+0x39c/0x4c8 kernel/futex/core.c:3594
lr : __do_sys_get_robust_list kernel/futex/core.c:3623 [inline]
lr : __se_sys_get_robust_list kernel/futex/core.c:3594 [inline]
lr : __arm64_sys_get_robust_list+0x374/0x4c8 kernel/futex/core.c:3594
sp : ffff800020117d20
x29: ffff800020117d20 x28: ffff0000da810000 x27: 0000000000000000
x26: 1fffe0001b502004 x25: 0000ffff98487440 x24: 0000000000000000
x23: dfff800000000000 x22: 0000000000000000 x21: 00000000fffffff2
x20: ffff0000da810024 x19: ffff0000da810000 x18: 0000000000000000
x17: 0000000000000000 x16: ffff8000083bec2c x15: 0000000000000000
x14: 0000000000000000 x13: 1ffff0000282e06b x12: 0000000000ff0100
x11: 0000000000000000 x10: 0000000000000000 x9 : 0000ffffffffffff
x8 : 0000000000000018 x7 : ffff800008750ed4 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000001
x2 : 0000000000000008 x1 : 0000000000000001 x0 : 0000000000000000
Call trace:
__do_sys_get_robust_list kernel/futex/core.c:3623 [inline]
__se_sys_get_robust_list kernel/futex/core.c:3594 [inline]
__arm64_sys_get_robust_list+0x39c/0x4c8 kernel/futex/core.c:3594
__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: 2a1f03f5 2a1f03e0 52800308 f8000948 (2a1503e1)
---[ end trace 624830973c7cc671 ]---
----------------
Code disassembly (best guess):
0: 2a1f03f5 mov w21, wzr
4: 2a1f03e0 mov w0, wzr
8: 52800308 mov w8, #0x18 // #24
c: f8000948 sttr x8, [x10]
* 10: 2a1503e1 mov w1, w21 <-- 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=12b801a2580000

kernel config: https://syzkaller.appspot.com/x/.config?x=9e47345638b85bd0
dashboard link: https://syzkaller.appspot.com/bug?extid=e7f4a39b04db725cb490
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=135c49a2580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16b801a2580000

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+e7f4a3...@syzkaller.appspotmail.com

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

CPU: 1 PID: 4245 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_get_robust_list kernel/futex/core.c:3623 [inline]
pc : __se_sys_get_robust_list kernel/futex/core.c:3594 [inline]
pc : __arm64_sys_get_robust_list+0x39c/0x4c8 kernel/futex/core.c:3594
lr : __do_sys_get_robust_list kernel/futex/core.c:3623 [inline]
lr : __se_sys_get_robust_list kernel/futex/core.c:3594 [inline]
lr : __arm64_sys_get_robust_list+0x374/0x4c8 kernel/futex/core.c:3594

sp : ffff80001fda7d20
x29: ffff80001fda7d20 x28: ffff0000d7b88000 x27: 0000000000000000
x26: 1fffe0001af71004 x25: 0000ffff9518b440 x24: 0000000000000000

x23: dfff800000000000 x22: 0000000000000000 x21: 00000000fffffff2

x20: ffff0000d7b88024 x19: ffff0000d7b88000 x18: 0000000000000000
x17: ffff800016d04000 x16: ffff8000083bec2c x15: ffff8000167e4500
x14: ffff0000d7b88a00 x13: 1ffff0000282e06b x12: 0000000000ff0100

x11: 0000000000000000 x10: 0000000000000000 x9 : 0000ffffffffffff
x8 : 0000000000000018 x7 : ffff800008750ed4 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000001
x2 : 0000000000000008 x1 : 0000000000000001 x0 : 0000000000000000
Call trace:
__do_sys_get_robust_list kernel/futex/core.c:3623 [inline]
__se_sys_get_robust_list kernel/futex/core.c:3594 [inline]
__arm64_sys_get_robust_list+0x39c/0x4c8 kernel/futex/core.c:3594
__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: 2a1f03f5 2a1f03e0 52800308 f8000948 (2a1503e1)

---[ end trace 4adcf882807b3455 ]---

----------------
Code disassembly (best guess):
0: 2a1f03f5 mov w21, wzr
4: 2a1f03e0 mov w0, wzr
8: 52800308 mov w8, #0x18 // #24
c: f8000948 sttr x8, [x10]
* 10: 2a1503e1 mov w1, w21 <-- trapping instruction


---

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