From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oa2-f9.google.com (mail-oa2-f9.google.com [74.125.231.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C840C38B7A6 for ; Mon, 14 Sep 2026 21:26:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.231.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789421189; cv=none; b=Xczy1r4aXLij9Sdr6Ra8NIEZ5Id7nuHtn7uP1i/lPjy+cc0lZiHULdlEzD4cYMzJ4LnmGhXkp3YRjCQezXZgy1CxG5MgxI4sc9wQxcJuN5N2ASsuJhpFf6PENxIXnAGvVX/jQV/G+iVowuATijvYaDDMd++tJaxKYst8+hQMVQY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789421189; c=relaxed/simple; bh=dWWNsdjuysMJ/2085tK0NW4f9jW++Y+Re2ydq5/YTrs=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=pjjHYxaNgdAfGg5XX3CF+OC/8F1Rp2SlrlEi0ZIAUCXXXDIAReR2znjDDCdSfQ/+ABfdMWPunSC2onIJqJUjR3NEsOaprHAyaj4QtToi3ECoX+9zThowvEdE/TGbZvV2YAO8Fli5Qv7o/6h2VnBmzNPvekmV+oxj0bR8LlJ1v8g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=74.125.231.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oa2-f9.google.com with SMTP id 586e51a60fabf-47bd4bcc3e2so1420027fac.1 for ; Mon, 14 Sep 2026 14:26:27 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1789421186; x=1790025986; h=content-type:to:from:subject:message-id:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=vvjwSBjsoRZGABnGVp2dTMSYiqE1jQGUEtvi1+gEewA=; b=aALGloN4ygHE4SBOqY0wux3hsfASliF83jPi3D8vDO9C5ujW3aQWQhF6eIzgS0Sm9h wCIJFQOkmVMTbWXl8Pm8BGbMrEbaGYUUoRy0pXQTreR/Qjs1si761JxaH0fj9c1p72ip FSd/gB+/W2PIZXGYn1FtH093bSlj+luey+Dah3pURGqdXJug4X3RwjffwlgVWAnrURl1 TOjOB3uVMSv9nWZ/3Hu5m3EHaetzRV3wJBr5rkmcTg4ItsxCwKuUOq/v6ahGtbWiR2u0 UCPuBdogrZ1FcF2KTjBcsYkQwqEM4EC0MnBZH3c3sroFa55XKDApkrKpmta9NbqEuG7m U3dQ== X-Forwarded-Encrypted: i=1; AKwUvBxv97mvYg9q9kIDcQ87wyMbYPYY778ugVhTINgK5oCTrQZ2cUlUBm7uWVm5pJQ0B/jU6OFhcSLUT+Ar9Yg=@vger.kernel.org X-Gm-Message-State: AFuF++kzHy2ZFVjHO65KxgScaSiCFg52KKO0YzYPuGfFp36/1REC2qaR eV3Jtzt652ZQ6POBB02SVoQ2Ry4dSvKX6Humphc6Vt7mCEQSc9e0XjaCbfD92R3dTmsrkZBITED hNFvd7ZXXVwzKYuSwwaH30+Ut7KUYMQZt5zRThLzc2WY3y05gJY3AzT79llY= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:3084:b0:6b7:83d6:292d with SMTP id 006d021491bc7-6c542831440mr2450704eaf.48.1789421186537; Mon, 14 Sep 2026 14:26:26 -0700 (PDT) Date: Mon, 14 Sep 2026 14:26:26 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6aa86682.f81106d8.2ab401.0056.GAE@google.com> Subject: [syzbot] [block?] WARNING: suspicious RCU usage in mas_start (2) From: syzbot To: axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, tom.leiming@gmail.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 704340f1cd0d Merge tag 'x86_urgent_for_7.3-rc4' of git://g.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16091925580000 kernel config: https://syzkaller.appspot.com/x/.config?x=8c5c3949d762a91f dashboard link: https://syzkaller.appspot.com/bug?extid=b48868c46e62c1c4cb2c compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=120f305e580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=117fb5f9580000 Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-704340f1.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/e02afc1c5927/vmlinux-704340f1.xz kernel image: https://storage.googleapis.com/syzbot-assets/09cb4a8b3309/bzImage-704340f1.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+b48868c46e62c1c4cb2c@syzkaller.appspotmail.com ============================= WARNING: suspicious RCU usage syzkaller #0 Not tainted ----------------------------- lib/maple_tree.c:720 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 locks held by syz.0.17/5926: 1, last CPU#0: #0: ffff888034a420a0 (&ctx->uring_lock){+.+.}-{4:4}, at: tctx_task_work_run+0x1cd/0xbf0 io_uring/tw.c:92 stack backtrace: CPU: 0 UID: 0 PID: 5926 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 lockdep_rcu_suspicious.cold+0x4f/0xb2 kernel/locking/lockdep.c:6972 mas_root lib/maple_tree.c:720 [inline] mas_start+0x621/0x7c0 lib/maple_tree.c:1250 mas_state_walk lib/maple_tree.c:3006 [inline] mas_walk+0x82/0x310 lib/maple_tree.c:4458 ublk_try_buf_match+0x469/0x7e0 drivers/block/ublk_drv.c:5639 ublk_init_iod+0x4a4/0x5b0 drivers/block/ublk_drv.c:521 ublk_setup_iod+0x145/0x2f0 drivers/block/ublk_drv.c:1536 ublk_dispatch_req+0x4e/0xb00 drivers/block/ublk_drv.c:1776 ublk_cmd_tw_cb+0xbe/0x110 drivers/block/ublk_drv.c:2067 tctx_task_work_run+0xabe/0xbf0 io_uring/tw.c:96 tctx_task_work+0x7a/0xa0 io_uring/tw.c:133 task_work_run+0x150/0x240 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x951/0x2ae0 kernel/exit.c:1011 do_group_exit+0xd5/0x2a0 kernel/exit.c:1154 __do_sys_exit_group kernel/exit.c:1165 [inline] __se_sys_exit_group kernel/exit.c:1163 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1163 x64_sys_call+0x1567/0x1570 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f35df99e159 Code: Unable to access opcode bytes at 0x7f35df99e12f. RSP: 002b:00007ffcaa2c82b8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f35df99e159 RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000003 R08: 0000000000000000 R09: 00007f35dfbec3e0 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f35dfbec3e0 R14: 0000000000000003 R15: 00007ffcaa2c8370 I/O error, dev ublkb0, sector 0 op 0x0:(READ) flags 0x800000 phys_seg 1 prio class 2 Buffer I/O error on dev ublkb0, logical block 0, async page read --- 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