From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D5F52C4CECD for ; Tue, 17 Sep 2019 15:29:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B1FB3206C2 for ; Tue, 17 Sep 2019 15:29:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729586AbfIQP26 (ORCPT ); Tue, 17 Sep 2019 11:28:58 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:38722 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1726546AbfIQP26 (ORCPT ); Tue, 17 Sep 2019 11:28:58 -0400 Received: (qmail 4307 invoked by uid 2102); 17 Sep 2019 11:28:57 -0400 Received: from localhost (sendmail-bs@127.0.0.1) by localhost with SMTP; 17 Sep 2019 11:28:57 -0400 Date: Tue, 17 Sep 2019 11:28:57 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Andrey Konovalov cc: Dmitry Vyukov , syzbot , Alexander Potapenko , Greg Kroah-Hartman , kai heng feng , Kernel development list , USB list , syzkaller-bugs , Subject: Re: KMSAN: uninit-value in usb_autopm_put_interface In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Tue, 17 Sep 2019, Andrey Konovalov wrote: > On Tue, Sep 17, 2019 at 4:51 PM Alan Stern wrote: > > > > On Tue, 17 Sep 2019, Dmitry Vyukov wrote: > > > > > On Mon, Sep 16, 2019 at 10:31 PM Alan Stern wrote: > > > > > > > > On Mon, 16 Sep 2019, syzbot wrote: > > > > > > > > > Hello, > > > > > > > > > > syzbot found the following crash on: > > > > > > > > > > HEAD commit: 014077b5 DO-NOT-SUBMIT: usb-fuzzer: main usb gadget fuzzer.. > > > > > git tree: https://github.com/google/kmsan.git master > > > > > console output: https://syzkaller.appspot.com/x/log.txt?x=16a7dde1600000 > > > > > kernel config: https://syzkaller.appspot.com/x/.config?x=f03c659d0830ab8d > > > > > dashboard link: https://syzkaller.appspot.com/bug?extid=e1d1a6e595adbd2458f1 > > > > > compiler: clang version 9.0.0 (/home/glider/llvm/clang > > > > > 80fee25776c2fb61e74c1ecb1a523375c2500b69) > > > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=176303e1600000 > > > > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10e8f23e600000 > > > > > > This is probably the same problem that was fixed in the Logitech driver > > > > earlier. The fix still appears to be in linux-next (commit > > > > 5f9242775bb6). > > > > > > > > Shouldn't syzbot wait until after the merge window before running tests > > > > like this? > > > > > > > > > Merge window is a weak notion and may be not enough either (all trees > > > do not necessary update at that point and syzbot does not necessary > > > rebuild all of them successfully). syzbot uses another criteria: if > > > you say a bug is fixed by commit X, it will wait until commit X > > > reaches all of tested trees and will report the same crash signature > > > again only after that. This procedure was specifically designed to not > > > produce duplicate reports about the same bug. > > > So either the bug wasn't really fixed, or this is another bug, or > > > syzbot was given a wrong commit. > > > > Hmmm. Which are the "tested trees"? > > > > This bug (e1d1a6e595adbd2458f1) is marked as a duplicate of > > 3cbe5cd105d2ad56a1df. The dashboard link says that bug was fixed by > > commit "HID: logitech: Fix general protection fault caused by Logitech > > driver" -- which is correct, as far as I know. > > > > That commit is present in linux-next, as mentioned above. As of 10:44 > > EDT today, it is not present in Linus's tree, according to > > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/drivers/hid/hid-lg.c > > > > (in fact, no commits affecting drivers/hid/hid-lg.c in that tree are > > dated after 2019-07-10). > > > > Furthermore, according to > > > > https://github.com/google/kmsan/blob/master/drivers/hid/hid-lg.c?h=014077b5 > > > > the source code actually used by syzbot for this test doesn't have that > > commit either. (BTW, is there any way to get a git log out of github? > > It would be nice not to have to download the whole source file -- and > > I'm not certain that this URL really does point to the version of the > > file that syzbot used.) > > > > So what's really going on? > > Please see my response. This report is a different manifestation of > the same Logitech bug. Hmmm. Does syzbot have any conception of which drivers are exercised by a particular test script? If it doesn't, there's no way to avoid getting these duplicate reports. Still, it is a little annoying for the developers. Alan Stern