From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id ECD74158A27 for ; Tue, 9 Apr 2024 23:46:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712706389; cv=none; b=IkIoThaqAB7fXapZ/GDIiuVKxWe3VqYzO0yg3JWOmTTD11SfLE8YlTx09J87FBiGQxlbpGGdqhOGeb/BHhQqqjwJeMOKbpwIlZoht5IXun5yOX7Z6T/j+f5rdNIhTQ0o0XksElkdyrRW06JKPcv4pRRaT1f/Xgbq2HLtK+sfNrc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712706389; c=relaxed/simple; bh=HBJVVaWz8JX97xuVuvJd+mzwWz9q/Je1QwskHu9FxZw=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=Rb/mNsFU2i20u5UwZYFcLafX1yW04ukYPplQuhJyJjwuvGLGoYIw14Qdldc2whelQV01oU8iluGwrv+6CNeUBrQDSFJW6tMyxsFeUDMsx2GL6P5QEZzTpWRQUd0h6n2zxkfFDZOsEegn553eLiAwSDU4BhiFgXpuVPiM4kkLcJw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=TLuqmX/p; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="TLuqmX/p" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5D00EC433C7; Tue, 9 Apr 2024 23:46:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1712706388; bh=HBJVVaWz8JX97xuVuvJd+mzwWz9q/Je1QwskHu9FxZw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=TLuqmX/pqFQ4BD7UUGrq4wDvvLzOgy+cEoJ1yiiSvfqGO/NRpbcCm5bPJzc/6ibuz wrEXi+kG3GfkyAzGC7N3ioZ+s9N0TslW9GMX6tcIkIn0GymjFJrdMNjvakRgyXcery 5g4sYF/iRu9uAfRr9DldP9smuzYaKUPp48SDBj3M= Date: Tue, 9 Apr 2024 16:46:27 -0700 From: Andrew Morton To: syzbot Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [mm?] general protection fault in hpage_collapse_scan_file Message-Id: <20240409164627.b4803e09c81c01ccb6f55601@linux-foundation.org> In-Reply-To: <0000000000009db84e0615a73698@google.com> References: <0000000000009db84e0615a73698@google.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Tue, 09 Apr 2024 03:16:20 -0700 syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 8568bb2ccc27 Add linux-next specific files for 20240405 > git tree: linux-next > console+strace: https://syzkaller.appspot.com/x/log.txt?x=152f4805180000 > kernel config: https://syzkaller.appspot.com/x/.config?x=48ca5acf8d2eb3bc > dashboard link: https://syzkaller.appspot.com/bug?extid=57adb2a4b9d206521bc2 > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1268258d180000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1256598d180000 Help. From a quick look this seems to be claiming that collapse_file() got to VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); with folio==NULL, but the code look solid regarding this. Given that we have a reproducer, can we expect the bot to perform a bisection for us?