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=-7.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,T_DKIMWL_WL_HIGH,USER_AGENT_MUTT 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 157B4C4321A for ; Tue, 11 Jun 2019 09:01:24 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E00C220657 for ; Tue, 11 Jun 2019 09:01:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="GH88/+a1"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="cDL76hPF" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E00C220657 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ffwll.ch Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Cc:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=7s5XwnZyvaGhYtZLZXsuy3+ii8fhiMEFqoA+XImCCAk=; b=GH88/+a1VBZj8f Wctaj0dKF17Y62APiOUckFEFUycNdOWzm/yC+LqW+uxjoOIHT1eWE4NmpvpbS8oB5CrW47c0G5lNh aCFxv0XUm6slWQztQkFbNf33a5UWoz+505dAf1pZ88NqaubAo6gxJtvmP05jdyZNBeGohSbbw0m30 DQXs3RImuq6C9M0z86N3JPrFsrhORJi9hPvqhS7W7NcRkJUFoM2g7vI8I1MxVjxnkwjGiRSkItle2 Bs/0cofI+o89atdrr7Sfu2hfOfNJ2G1NPVBX5B9QA4lB0VXMyHWEPeGb+D96l1ZUFQsvNSfcZelLr eNM0Zt0ZbUxT6zO7j5SA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1haceg-0006Sy-Tq; Tue, 11 Jun 2019 09:01:23 +0000 Received: from mail-ed1-x541.google.com ([2a00:1450:4864:20::541]) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1hacec-0006Ri-2i for linux-arm-kernel@lists.infradead.org; Tue, 11 Jun 2019 09:01:20 +0000 Received: by mail-ed1-x541.google.com with SMTP id a14so17022566edv.12 for ; Tue, 11 Jun 2019 02:01:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=sender:date:from:to:subject:message-id:mail-followup-to:references :mime-version:content-disposition:in-reply-to:user-agent; bh=GgEHcwpFv/NSxB4nhb8sGjpQD1wZwWQuCULhK2h4yOs=; b=cDL76hPFo48JwMplskS84bSNvgL97E7I7IHIAV6EnKwW0ST0eyJj45wq/IKb/QFdui FRj3NwSHFucvkvROyxH49N4dxfndyy+6oD0eeSiDXHHFCvzG2rFCwjTApsE06XM0wLH1 8mK7xFxkELVMJ0ejg1B73BDTj2uzBbZ53dDug= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:subject:message-id :mail-followup-to:references:mime-version:content-disposition :in-reply-to:user-agent; bh=GgEHcwpFv/NSxB4nhb8sGjpQD1wZwWQuCULhK2h4yOs=; b=pC1VBlIZvZ+Ar17QMiHH7uRcf9wtbuLEDk5vATtgxsTQguNRXnjfpq8LtKv7EQh/gd 3noyUAjyYzXxzaRdnLmA8fn2Z9Hu2dLGaO3Dc0WvGdw93PUWVPDRAguD+pc90u3cWyRQ J8nEW8RNNcXFcF4VykPBq+s8Rbjen0HnKi5bV/S81khUlYHzmbygXw21IZ8ZsWf/qJqX lD6QnkCtk8SGMt1phcjeV5pTLFXU2Segouywz4Yy+y1IpJXASaURW8eEo/1Gn75Lq+LH LAP/DaxzfFbMkuiy/hBs1isrD5Gt7OZNz2i5mzYve1N1l0hPOiOxvwnDCZIje3WVirZn Z24Q== X-Gm-Message-State: APjAAAUIqT9ZvOrR/yhnYziKmQQrfIQr0dD4NS1y3an7NLCKjz2AI6Y4 O8V/Eu5eStVvgtziRunSwhThxg== X-Google-Smtp-Source: APXvYqyXcj5UdsqzqojLSWbj0IZz3C5Eifs54JPrPx/Zay91g0pCgveR+6PscizV8JsXUwLUpIqVng== X-Received: by 2002:a17:907:20db:: with SMTP id qq27mr44209049ejb.30.1560243673593; Tue, 11 Jun 2019 02:01:13 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:569e:0:3106:d637:d723:e855]) by smtp.gmail.com with ESMTPSA id h26sm206855ejc.71.2019.06.11.02.01.11 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Tue, 11 Jun 2019 02:01:12 -0700 (PDT) Date: Tue, 11 Jun 2019 11:01:10 +0200 From: Daniel Vetter To: Dmitry Vyukov , syzbot , David Airlie , Alexei Starovoitov , bpf , Daniel Borkmann , David Miller , DRI , hawk@kernel.org, Jakub Kicinski , John Fastabend , Martin KaFai Lau , Linux ARM , LKML , maxime.ripard@bootlin.com, netdev , paul.kocialkowski@bootlin.com, Song Liu , syzkaller-bugs , wens@csie.org, xdp-newbies@vger.kernel.org, Yonghong Song Subject: Re: WARNING in bpf_jit_free Message-ID: <20190611090110.GY21222@phenom.ffwll.local> Mail-Followup-To: Dmitry Vyukov , syzbot , David Airlie , Alexei Starovoitov , bpf , Daniel Borkmann , David Miller , DRI , hawk@kernel.org, Jakub Kicinski , John Fastabend , Martin KaFai Lau , Linux ARM , LKML , maxime.ripard@bootlin.com, netdev , paul.kocialkowski@bootlin.com, Song Liu , syzkaller-bugs , wens@csie.org, xdp-newbies@vger.kernel.org, Yonghong Song References: <000000000000e92d1805711f5552@google.com> <000000000000381684058ace28e5@google.com> <20190611080431.GP21222@phenom.ffwll.local> <20190611085123.GU21222@phenom.ffwll.local> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190611085123.GU21222@phenom.ffwll.local> X-Operating-System: Linux phenom 4.14.0-3-amd64 User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190611_020118_252995_EF734682 X-CRM114-Status: GOOD ( 29.11 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Jun 11, 2019 at 10:51:23AM +0200, Daniel Vetter wrote: > On Tue, Jun 11, 2019 at 10:33:21AM +0200, Dmitry Vyukov wrote: > > On Tue, Jun 11, 2019 at 10:04 AM Daniel Vetter wrote: > > > > > > On Sat, Jun 08, 2019 at 04:22:06AM -0700, syzbot wrote: > > > > syzbot has found a reproducer for the following crash on: > > > > > > > > HEAD commit: 79c3ba32 Merge tag 'drm-fixes-2019-06-07-1' of git://anong.. > > > > git tree: upstream > > > > console output: https://syzkaller.appspot.com/x/log.txt?x=1201b971a00000 > > > > kernel config: https://syzkaller.appspot.com/x/.config?x=60564cb52ab29d5b > > > > dashboard link: https://syzkaller.appspot.com/bug?extid=2ff1e7cb738fd3c41113 > > > > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14a3bf51a00000 > > > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=120d19f2a00000 > > > > > > Looking at the reproducer I don't see any calls to ioctl which could end > > > up anywhere in drm. > > > > > > > > The bug was bisected to: > > > > > > > > commit 0fff724a33917ac581b5825375d0b57affedee76 > > > > Author: Paul Kocialkowski > > > > Date: Fri Jan 18 14:51:13 2019 +0000 > > > > > > > > drm/sun4i: backend: Use explicit fourcc helpers for packed YUV422 check > > > > > > And most definitely not in drm/sun4i. You can only hit this if you have > > > sun4i and run on arm, which per your config isn't the case. > > > > > > tldr; smells like bisect gone wrong. > > > -Daniel > > > > From the bisection log it looks like the bug is too hard to trigger > > for reliable bisection. So it probably classified one bad commit as > > good. But it should got quite close to the right one. > > Well statistically it'll get close, since there's a fair chance that it's > one of the later bisect results that got mischaracterized. > > But you can be equally unlucky, and if it's one of the earliers, then it > can easily be a few thousand commits of. Looking at the log it's mostly > bad, with a few good sprinkled in, which could just be reproduction > failures. So might very well be that the very first "good" result is > wrong. And that very first "good" decision cuts away a big pile of bpf > related commits. The next "good" decision then only cuts away a pile of > drm commits, but at that point you're already off the rails most likely. > > I'd say re-test on f90d64483ebd394958841f67f8794ab203b319a7 a few times, > I'm willing to bet that one is actually bad. btw if this theory is right, we have a 1-in-4 chance of a spurious "good" with your test. If you get 10 repeated "good" then that should be good enough to make playing the lottery a better endeavor :-) -Daniel > > Cheers, Daniel > > > > > > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1467550f200000 > > > > final crash: https://syzkaller.appspot.com/x/report.txt?x=1667550f200000 > > > > console output: https://syzkaller.appspot.com/x/log.txt?x=1267550f200000 > > > > > > > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > > > > Reported-by: syzbot+2ff1e7cb738fd3c41113@syzkaller.appspotmail.com > > > > Fixes: 0fff724a3391 ("drm/sun4i: backend: Use explicit fourcc helpers for > > > > packed YUV422 check") > > > > > > > > WARNING: CPU: 0 PID: 8951 at kernel/bpf/core.c:851 bpf_jit_free+0x157/0x1b0 > > > > Kernel panic - not syncing: panic_on_warn set ... > > > > CPU: 0 PID: 8951 Comm: kworker/0:0 Not tainted 5.2.0-rc3+ #23 > > > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > > > > Google 01/01/2011 > > > > Workqueue: events bpf_prog_free_deferred > > > > Call Trace: > > > > __dump_stack lib/dump_stack.c:77 [inline] > > > > dump_stack+0x172/0x1f0 lib/dump_stack.c:113 > > > > panic+0x2cb/0x744 kernel/panic.c:219 > > > > __warn.cold+0x20/0x4d kernel/panic.c:576 > > > > report_bug+0x263/0x2b0 lib/bug.c:186 > > > > fixup_bug arch/x86/kernel/traps.c:179 [inline] > > > > fixup_bug arch/x86/kernel/traps.c:174 [inline] > > > > do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:272 > > > > do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:291 > > > > invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:986 > > > > RIP: 0010:bpf_jit_free+0x157/0x1b0 > > > > Code: 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 5d 48 b8 00 02 00 00 > > > > 00 00 ad de 48 39 43 70 0f 84 05 ff ff ff e8 f9 b5 f4 ff <0f> 0b e9 f9 fe ff > > > > ff e8 bd 53 2d 00 e9 d9 fe ff ff 48 89 7d e0 e8 > > > > RSP: 0018:ffff88808886fcb0 EFLAGS: 00010293 > > > > RAX: ffff88808cb6c480 RBX: ffff88809051d280 RCX: ffffffff817ae68d > > > > RDX: 00000000> > > > > > > > -- > > > Daniel Vetter > > > Software Engineer, Intel Corporation > > > http://blog.ffwll.ch > > > > > > -- > > > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > > > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com. > > > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/20190611080431.GP21222%40phenom.ffwll.local. > > > For more options, visit https://groups.google.com/d/optout.00000000 RSI: ffffffff817bf0f7 RDI: ffff88809051d2f0 > > > > RBP: ffff88808886fcd0 R08: 1ffffffff14ccaa8 R09: fffffbfff14ccaa9 > > > > R10: fffffbfff14ccaa8 R11: ffffffff8a665547 R12: ffffc90001925000 > > > > R13: ffff88809051d2e8 R14: ffff8880a0e43900 R15: ffff8880ae834840 > > > > bpf_prog_free_deferred+0x27a/0x350 kernel/bpf/core.c:1984 > > > > process_one_work+0x989/0x1790 kernel/workqueue.c:2269 > > > > worker_thread+0x98/0xe40 kernel/workqueue.c:2415 > > > > kthread+0x354/0x420 kernel/kthread.c:255 > > > > ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 > > > > Kernel Offset: disabled > > > > Rebooting in 86400 seconds.. > > -- > Daniel Vetter > Software Engineer, Intel Corporation > http://blog.ffwll.ch -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel