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] [kernel?] Internal error in futex_wake_op syzbot
2026-09-04 5:40 ` Thomas Gleixner [this message]
2026-09-04 18:04 ` Will Deacon
2026-09-05 10:31 ` Thomas Gleixner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=877bl1a811.ffs@fw13 \
--to=tglx@kernel.org \
--cc=andrealmeid@igalia.com \
--cc=catalin.marinas@arm.com \
--cc=dave@stgolabs.net \
--cc=dvhart@infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=syzbot+417a6b7c02d5d03f9aa6@syzkaller.appspotmail.com \
--cc=syzkaller-bugs@googlegroups.com \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.