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[156.34.48.30]) by smtp.gmail.com with ESMTPSA id x29sm10363864qtv.80.2020.08.14.10.07.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 14 Aug 2020 10:07:08 -0700 (PDT) Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1k6dAZ-006l92-QG; Fri, 14 Aug 2020 14:07:07 -0300 Date: Fri, 14 Aug 2020 14:07:07 -0300 From: Jason Gunthorpe To: Jack Leadford Cc: Joe Perches , Leon Romanovsky , Greg Kroah-Hartman , Peilin Ye , Santosh Shilimkar , "David S. Miller" , Jakub Kicinski , Dan Carpenter , Arnd Bergmann , linux-kernel-mentees@lists.linuxfoundation.org, netdev@vger.kernel.org, linux-rdma@vger.kernel.org, rds-devel@oss.oracle.com, linux-kernel@vger.kernel.org Subject: Re: [Linux-kernel-mentees] [PATCH net] rds: Prevent kernel-infoleak in rds_notify_queue_get() Message-ID: <20200814170707.GV24045@ziepe.ca> References: <20200731142148.GA1718799@kroah.com> <20200731143604.GF24045@ziepe.ca> <20200731171924.GA2014207@kroah.com> <20200801053833.GK75549@unreal> <20200802221020.GN24045@ziepe.ca> <20200802222843.GP24045@ziepe.ca> <60584f4c0303106b42463ddcfb108ec4a1f0b705.camel@perches.com> <20200803230627.GQ24045@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Sat, Aug 08, 2020 at 03:57:33PM -0700, Jack Leadford wrote: > Hello! > > Thanks to Jason for getting this conversation back on track. > > Yes: in general, {} or a partial initializer /will/ zero padding bits. > > However, there is a bug in some versions of GCC where {} will /not/ zero > padding bits; actually, Jason's test program in this mail > https://lore.kernel.org/lkml/20200731143604.GF24045@ziepe.ca/ > has the right ingredients to trigger the bug, but the GCC > versions used are outside of the bug window. :) It seems fine, at least Godbolt doesn't show a bug with that code. Can you share the test that does fail? This seems like the sort of security sensitive bug that should be addressed in gcc, not worked around in the kernel code :\ Jason