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McKenney" To: Dmitry Vyukov Cc: Andrea Parri , Mark Rutland , Dhaval Giani , Sasha Levin , shuah , Kevin Hilman , Tim Bird , LKML , Steven Rostedt , "Carpenter,Dan" , Matthew Wilcox , gustavo padovan , knut omang , Nick Desaulniers , Alan Stern Subject: Re: Linux Testing Microconference at LPC Reply-To: paulmck@linux.ibm.com References: <20190423102250.GA56999@lakrids.cambridge.arm.com> <20190512004008.GA6062@andrea> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 19052314-0052-0000-0000-000003C5FE0C X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00011149; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000286; SDB=6.01207468; UDB=6.00634135; IPR=6.00988448; MB=3.00027018; MTD=3.00000008; XFM=3.00000015; UTC=2019-05-23 14:04:00 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19052314-0053-0000-0000-00006103E0A6 Message-Id: <20190523140356.GN28207@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-05-23_12:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1905230097 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 22, 2019 at 05:52:17PM +0200, Dmitry Vyukov wrote: > On Sun, May 12, 2019 at 2:40 AM Andrea Parri > wrote: > > > > On Tue, Apr 23, 2019 at 11:22:50AM +0100, Mark Rutland wrote: > > > On Thu, Apr 11, 2019 at 10:37:51AM -0700, Dhaval Giani wrote: > > > > Hi Folks, > > > > > > > > This is a call for participation for the Linux Testing microconference > > > > at LPC this year. > > > > > > > > For those who were at LPC last year, as the closing panel mentioned, > > > > testing is probably the next big push needed to improve quality. From > > > > getting more selftests in, to regression testing to ensure we don't > > > > break realtime as more of PREEMPT_RT comes in, to more stable distros, > > > > we need more testing around the kernel. > > > > > > > > We have talked about different efforts around testing, such as fuzzing > > > > (using syzkaller and trinity), automating fuzzing with syzbot, 0day > > > > testing, test frameworks such as ktests, smatch to find bugs in the > > > > past. We want to push this discussion further this year and are > > > > interested in hearing from you what you want to talk about, and where > > > > kernel testing needs to go next. > > > > > > I'd be interested to discuss what we could do with annotations and > > > compiler instrumentation to make the kernel more amenable to static and > > > dynamic analysis (and to some extent, documenting implicit > > > requirements). > > > > > > One idea that I'd like to explore in the context of RT is to annotate > > > function signatures with their required IRQ/preempt context, such that > > > we could dynamically check whether those requirements were violated > > > (even if it didn't happen to cause a problem at that point in time), and > > > static analysis would be able to find some obviously broken usage. I had > > > some rough ideas of how to do the dynamic part atop/within ftrace. Maybe > > > there are similar problems elsewhere. > > > > > > I know that some clang folk were interested in similar stuff. IIRC Nick > > > Desaulniers was interested in whether clang's thread safety analysis > > > tooling could be applied to the kernel (e.g. based on lockdep > > > annotations). > > > > FWIW, I'd also be interested in discussing these developments. > > > > There have been several activities/projects related to such "tooling" > > (thread safety analysis) recently: I could point out the (brand new) > > Google Summer of Code "Applying Clang Thread Safety Analyser to Linux > > Kernel" project [1] and (for the "dynamic analysis" side) the efforts > > to revive the Kernel Thread sanitizer [2]. I should also mention the > > efforts to add (support for) "unmarked" accesses and to formalize the > > notion of "data race" in the memory consistency model [3]. > > > > So, again, I'd welcome a discussion on these works/ideas. > > > > Thanks, > > Andrea > > I would be interested in discussing all of this too: thread safety > annotations, ktsan, unmarked accesses. Sounds like a great discussion! Might this fit into Sasha Levin's and Dhaval Giani's proposed Testing & Fuzzing MC? Thanx, Paul