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Tsirkin" Cc: Eric Dumazet , syzbot , davem@davemloft.net, herbert@gondor.apana.org.au, jiri@nvidia.com, kuba@kernel.org, leonro@nvidia.com, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, mpm@selenic.com, netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com References: <000000000000a4cd2105cf441e76@google.com> <6c7e48b9-5204-352f-18e7-26b13d70f966@redhat.com> <20211027031847-mutt-send-email-mst@kernel.org> From: Laurent Vivier In-Reply-To: <20211027031847-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 27/10/2021 09:20, Michael S. Tsirkin wrote: > On Wed, Oct 27, 2021 at 09:08:04AM +0200, Laurent Vivier wrote: >> On 27/10/2021 00:34, Eric Dumazet wrote: >>> >>> >>> On 10/26/21 9:39 AM, syzbot wrote: >>>> Hello, >>>> >>>> syzbot found the following issue on: >>>> >>>> HEAD commit: 9ae1fbdeabd3 Add linux-next specific files for 20211025 >>>> git tree: linux-next >>>> console output: https://syzkaller.appspot.com/x/log.txt?x=1331363cb00000 >>>> kernel config: https://syzkaller.appspot.com/x/.config?x=aeb17e42bc109064 >>>> dashboard link: https://syzkaller.appspot.com/bug?extid=b86736b5935e0d25b446 >>>> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 >>>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=116ce954b00000 >>>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=132fcf62b00000 >>>> >>>> The issue was bisected to: >>>> >>>> commit 22849b5ea5952d853547cc5e0651f34a246b2a4f >>>> Author: Leon Romanovsky >>>> Date: Thu Oct 21 14:16:14 2021 +0000 >>>> >>>> devlink: Remove not-executed trap policer notifications >>> >>> More likely this came with >>> >>> caaf2874ba27b92bca6f0298bf88bad94067ec37 hwrng: virtio - don't waste entropy >>> >> >> I'm going to have a look. >> >> Thanks, >> Laurent > > How bad is it if we just drop this and waste some bytes of entropy? > I don't think it's bad at all. In most of the cases we should use the full buffer. So, you can drop, I will re-submit them later with a fix. Thanks, Laurent