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Thu, 25 Dec 2025 06:40:02 -0500 X-MC-Unique: gYy8oxAZPXKg1LD7aSlunw-1 X-Mimecast-MFC-AGG-ID: gYy8oxAZPXKg1LD7aSlunw_1766662801 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 5BBC01956088; Thu, 25 Dec 2025 11:40:01 +0000 (UTC) Received: from fedora (unknown [10.72.116.23]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 9A66319560A7; Thu, 25 Dec 2025 11:39:57 +0000 (UTC) Date: Thu, 25 Dec 2025 19:39:52 +0800 From: Ming Lei To: syzbot Cc: axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [block?] WARNING in wbt_init_enable_default Message-ID: References: <694ce8fd.050a0220.35954c.0035.GAE@google.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <694ce8fd.050a0220.35954c.0035.GAE@google.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 On Wed, Dec 24, 2025 at 11:34:21PM -0800, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: b927546677c8 Merge tag 'dma-mapping-6.19-2025-12-22' of gi.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=11dc8b92580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=a94030c847137a18 > dashboard link: https://syzkaller.appspot.com/bug?extid=71fcf20f7c1e5043d78c > compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10515f1a580000 > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/b27369f4b013/disk-b9275466.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/3b2d81c4be86/vmlinux-b9275466.xz > kernel image: https://storage.googleapis.com/syzbot-assets/89c2ad4f36b6/bzImage-b9275466.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+71fcf20f7c1e5043d78c@syzkaller.appspotmail.com > > ------------[ cut here ]------------ > WARNING: block/blk-wbt.c:741 at wbt_init_enable_default+0x4e/0x60 block/blk-wbt.c:741, CPU#0: syz.1.439/7602 > Modules linked in: > CPU: 0 UID: 0 PID: 7602 Comm: syz.1.439 Not tainted syzkaller #0 PREEMPT(full) > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 > RIP: 0010:wbt_init_enable_default+0x4e/0x60 block/blk-wbt.c:741 Looks like 'echo > /sys/block/loop0/queue/queue_wb_lat' creates wbt first, then -EBUSY is triggered. Seems -EBUSY should be filtered for warn here. Thanks, Ming