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[2001:44b8:1113:6700:7daa:d2ea:7edb:cfe8]) by smtp.gmail.com with ESMTPSA id z64sm12695976pfz.23.2019.12.05.05.10.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Dec 2019 05:10:45 -0800 (PST) From: Daniel Axtens To: Daniel Borkmann Cc: Dmitry Vyukov , syzbot , kasan-dev , Andrii Nakryiko , Alexei Starovoitov , bpf , Martin KaFai Lau , LKML , netdev , Song Liu , syzkaller-bugs , Yonghong Song , Andrey Ryabinin Subject: Re: BUG: unable to handle kernel paging request in pcpu_alloc In-Reply-To: <20191205125900.GB29780@localhost.localdomain> References: <000000000000314c120598dc69bd@google.com> <877e3be6eu.fsf@dja-thinkpad.axtens.net> <20191205125900.GB29780@localhost.localdomain> Date: Fri, 06 Dec 2019 00:10:41 +1100 Message-ID: <871rtiex4e.fsf@dja-thinkpad.axtens.net> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Daniel Borkmann writes: > On Thu, Dec 05, 2019 at 03:35:21PM +1100, Daniel Axtens wrote: >> >> HEAD commit: 1ab75b2e Add linux-next specific files for 20191203 >> >> git tree: linux-next >> >> console output: https://syzkaller.appspot.com/x/log.txt?x=10edf2eae00000 >> >> kernel config: https://syzkaller.appspot.com/x/.config?x=de1505c727f0ec20 >> >> dashboard link: https://syzkaller.appspot.com/bug?extid=82e323920b78d54aaed5 >> >> compiler: gcc (GCC) 9.0.0 20181231 (experimental) >> >> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=156ef061e00000 >> >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11641edae00000 >> >> >> >> IMPORTANT: if you fix the bug, please add the following tag to the commit: >> >> Reported-by: syzbot+82e323920b78d54aaed5@syzkaller.appspotmail.com >> > >> > +Daniel, is it the same as: >> > https://syzkaller.appspot.com/bug?id=f6450554481c55c131cc23d581fbd8ea42e63e18 >> > If so, is it possible to make KASAN detect this consistently with the >> > same crash type so that syzbot does not report duplicates? >> >> It looks like both of these occur immediately after failure injection. I >> think my assumption that I could ignore the chance of failures in the >> per-cpu allocation path will have to be revisited. That's annoying. >> >> I'll try to spin something today but Andrey feel free to pip me at the >> post again :) >> >> I'm not 100% confident to call them dups just yet, but I'm about 80% >> confident that they are. > > Ok. Double checked BPF side yesterday night, but looks sane to me and the > fault also hints into pcpu_alloc() rather than BPF code. Daniel, from your > above reply, I read that you are aware of how the bisected commit would > have caused the fault? Yes, this one is on me - I did not take into account the brutal efficiency of the fault injector when implementing my KASAN support for vmalloc areas. I have a fix, I'm just doing final tests now. Regards, Daniel > > Thanks, > Daniel > > -- > You received this message because you are subscribed to the Google Groups "kasan-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an email to kasan-dev+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/kasan-dev/20191205125900.GB29780%40localhost.localdomain.