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From: syzbot <syzbot+6cdbd5e494b199d820c3@syzkaller.appspotmail.com>
To: akpm@linux-foundation.org, bp@alien8.de,
	dave.hansen@linux.intel.com,  hpa@zytor.com,
	linux-kernel@vger.kernel.org, mingo@redhat.com,
	 senozhatsky@chromium.org, syzkaller-bugs@googlegroups.com,
	tglx@kernel.org,  tglx@linutronix.de, x86@kernel.org
Subject: [syzbot] [kernel?] WARNING in do_clear_cpu_cap
Date: Fri, 31 Jul 2026 10:13:34 -0700	[thread overview]
Message-ID: <6a6cd7be.1aa927e4.17d4bf.0005.GAE@google.com> (raw)

Hello,

syzbot found the following issue on:

HEAD commit:    11028ab62899 Merge tag 'probes-fixes-v7.2-rc5' of git://gi..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=14e3d9b9580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=cb17729fb04b1e3a
dashboard link: https://syzkaller.appspot.com/bug?extid=6cdbd5e494b199d820c3
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13b271b9580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=118a97b1580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/bc967be819a3/disk-11028ab6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6e9f003c9cc8/vmlinux-11028ab6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5c292926486f/bzImage-11028ab6.xz

The issue was bisected to:

commit 684826f8271ad97580b138b9ffd462005e470b99
Author: Sergey Senozhatsky <senozhatsky@chromium.org>
Date:   Wed Sep 11 02:54:56 2024 +0000

    zram: free secondary algorithms names

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=175175b9580000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=14d175b9580000
console output: https://syzkaller.appspot.com/x/log.txt?x=10d175b9580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6cdbd5e494b199d820c3@syzkaller.appspotmail.com
Fixes: 684826f8271a ("zram: free secondary algorithms names")

Disabled fast string operations
------------[ cut here ]------------
alternatives_patched
WARNING: arch/x86/kernel/cpu/cpuid-deps.c:127 at do_clear_cpu_cap+0x416/0x450 arch/x86/kernel/cpu/cpuid-deps.c:127, CPU#1: swapper/1/0
Modules linked in:
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G S                  syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [S]=CPU_OUT_OF_SPEC
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:do_clear_cpu_cap+0x416/0x450 arch/x86/kernel/cpu/cpuid-deps.c:127
Code: 00 00 00 75 2d 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d e9 4c 42 d8 09 cc e8 d6 8c 56 00 90 0f 0b 90 eb 94 e8 cb 8c 56 00 90 <0f> 0b 90 e9 06 fd ff ff e8 dd 75 d4 09 48 c7 c1 58 83 af 8f 80 e1
RSP: 0000:ffffc900001d7ba0 EFLAGS: 00010093
RAX: ffffffff816f4e25 RBX: dffffc0000000001 RCX: ffff88801cec8000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900001d7cd8 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed10170e4903 R12: 0000000000000070
R13: dffffc0000000000 R14: 0000000000000001 R15: 0000000000000070
FS:  0000000000000000(0000) GS:ffff888125d41000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000000dfb0000 CR4: 00000000003506b0
Call Trace:
 <TASK>
 early_init_intel+0xb3d/0xea0 arch/x86/kernel/cpu/intel.c:309
 init_intel+0x28/0x780 arch/x86/kernel/cpu/intel.c:528
 identify_cpu+0xc7a/0x3660 arch/x86/kernel/cpu/common.c:2053
 identify_secondary_cpu+0xaa/0x160 arch/x86/kernel/cpu/common.c:2177
 ap_starting+0x9c/0x150 arch/x86/kernel/smpboot.c:190
 start_secondary+0x66/0x110 arch/x86/kernel/smpboot.c:280
 common_startup_64+0x13e/0x157
 </TASK>


---
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.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection

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:
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If the report is a duplicate of another one, reply with:
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If you want to undo deduplication, reply with:
#syz undup

             reply	other threads:[~2026-07-31 17:13 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-31 17:13 syzbot [this message]
2026-07-31 17:35 ` [syzbot] [kernel?] WARNING in do_clear_cpu_cap Andrew Morton
2026-07-31 18:22   ` Borislav Petkov

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