From: Thomas Gleixner <tglx@kernel.org>
To: syzbot <syzbot+417a6b7c02d5d03f9aa6@syzkaller.appspotmail.com>,
andrealmeid@igalia.com, dave@stgolabs.net, dvhart@infradead.org,
linux-kernel@vger.kernel.org, mingo@redhat.com,
peterz@infradead.org, syzkaller-bugs@googlegroups.com
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>
Subject: Re: [syzbot] [kernel?] Internal error in futex_wake_op
Date: Fri, 04 Sep 2026 07:40:42 +0200 [thread overview]
Message-ID: <877bl1a811.ffs@fw13> (raw)
In-Reply-To: <6a908778.1d9ded08.62e62.00dc.GAE@google.com>
On Thu, Aug 27 2026 at 11:52, syzbot wrote:
CC+: ARM64 people...
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 68f892e99df9 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=13dc7415580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=d1128bc53f2ef7f3
> dashboard link: https://syzkaller.appspot.com/bug?extid=417a6b7c02d5d03f9aa6
> compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
> userspace arch: arm64
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1512d625580000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13e2859e580000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/f98dd20a7b98/disk-68f892e9.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/441f1ad32549/vmlinux-68f892e9.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/8da5227b7dc8/Image-68f892e9.gz.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+417a6b7c02d5d03f9aa6@syzkaller.appspotmail.com
>
> futex_wake_op: syz.0.17 tries to shift op by 144; fix this program
> Internal error: synchronous external abort: 0000000096000010 [#1] SMP
> Modules linked in:
> CPU: 0 UID: 0 PID: 4917 Comm: syz.0.17 Tainted: G M syzkaller #0 PREEMPT
> Tainted: [M]=MACHINE_CHECK
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/07/2026
> pstate: 83000005 (Nzcv daif -PAN -UAO +TCO +DIT -SSBS BTYPE=--)
> pc : __llsc_futex_atomic_or arch/arm64/include/asm/futex.h:51 [inline]
> pc : __futex_atomic_or arch/arm64/include/asm/futex.h:239 [inline]
> pc : arch_futex_atomic_op_inuser arch/arm64/include/asm/futex.h:269 [inline]
> pc : futex_atomic_op_inuser kernel/futex/waitwake.c:251 [inline]
> pc : futex_wake_op+0x450/0xfe8 kernel/futex/waitwake.c:302
> lr : mte_enable_tco arch/arm64/include/asm/mte-kasan.h:62 [inline]
> lr : uaccess_enable_privileged arch/arm64/include/asm/uaccess.h:147 [inline]
> lr : __llsc_futex_atomic_or arch/arm64/include/asm/futex.h:51 [inline]
> lr : __futex_atomic_or arch/arm64/include/asm/futex.h:239 [inline]
> lr : arch_futex_atomic_op_inuser arch/arm64/include/asm/futex.h:269 [inline]
> lr : futex_atomic_op_inuser kernel/futex/waitwake.c:251 [inline]
> lr : futex_wake_op+0x43c/0xfe8 kernel/futex/waitwake.c:302
> sp : ffff800093197980
> x29: ffff800093197b40 x28: 0000000000010000 x27: 0000000000000000
> x26: 1fffe00018d2a3ad x25: dfff800000000000 x24: ffff0000c6951d40
> x23: ffff0000c6951d6c x22: 0000000000000002 x21: 1fffe00018d2a685
> x20: ffff0000c1df3780 x19: ffff0000c695342c x18: 0000000000000000
> x17: 72676f7270207369 x16: 687420786966203b x15: 3434312079622070
> x14: 6f20746669687320 x13: 0000000000000001 x12: 0000000000000000
> x11: 0000000000000000 x10: 00000000fffffff5 x9 : 0000000000000000
> x8 : 0000000000000080 x7 : ffff80008048c60c x6 : 0000000000000000
> x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff8000805b0678
> x2 : 0000000000000002 x1 : ffff0000c6951d40 x0 : 0000000000000000
> Call trace:
> __llsc_futex_atomic_or arch/arm64/include/asm/futex.h:51 [inline] (P)
> __futex_atomic_or arch/arm64/include/asm/futex.h:239 [inline] (P)
> arch_futex_atomic_op_inuser arch/arm64/include/asm/futex.h:269 [inline] (P)
> futex_atomic_op_inuser kernel/futex/waitwake.c:251 [inline] (P)
> futex_wake_op+0x450/0xfe8 kernel/futex/waitwake.c:302 (P)
> do_futex+0x200/0x378 kernel/futex/syscalls.c:144
> __do_sys_futex kernel/futex/syscalls.c:210 [inline]
> __se_sys_futex kernel/futex/syscalls.c:191 [inline]
> __arm64_sys_futex+0x2e4/0x418 kernel/futex/syscalls.c:191
> __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
> invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
> el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
> do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
> el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:758
> el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:777
> el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590
> Code: d500409f 1280014a f94057eb f9800171 (885f7d76)
> ---[ end trace 0000000000000000 ]---
> ----------------
> Code disassembly (best guess):
> 0: d500409f msr pan, #0x0
> 4: 1280014a mov w10, #0xfffffff5 // #-11
> 8: f94057eb ldr x11, [sp, #168]
> c: f9800171 prfm pstl1strm, [x11]
> * 10: 885f7d76 ldxr w22, [x11] <-- trapping instruction
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
>
> If the report is already addressed, let syzbot know by replying with:
> #syz fix: exact-commit-title
>
> If you want syzbot to run the reproducer, reply with:
> #syz test: git://repo/address.git branch-or-commit-hash
> If you attach or paste a git patch, syzbot will apply it before testing.
>
> If you want to overwrite report's subsystems, reply with:
> #syz set subsystems: new-subsystem
> (See the list of subsystem names on the web dashboard)
>
> If the report is a duplicate of another one, reply with:
> #syz dup: exact-subject-of-another-report
>
> If you want to undo deduplication, reply with:
> #syz undup
next prev parent reply other threads:[~2026-09-04 5:40 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-27 18:52 syzbot
2026-09-04 5:40 ` Thomas Gleixner [this message]
2026-09-04 18:04 ` Will Deacon
2026-09-05 10:31 ` Thomas Gleixner
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