From mboxrd@z Thu Jan 1 00:00:00 1970 From: Cyril Hrubis Date: Wed, 17 Jul 2019 11:46:14 +0200 Subject: [LTP] Question about kernel/syscall/signal/signal06.c In-Reply-To: <56f854e2-9cc6-4725-3182-ff83e106ee23@windriver.com> References: <56f854e2-9cc6-4725-3182-ff83e106ee23@windriver.com> Message-ID: <20190717094614.GA9539@rei> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ltp@lists.linux.it Hi! > I find signal06 fails on qemux86-64 when qemu has a small number cores, > e.g. "qemu -smp 1/2/4/6". > > ERROR INFO: > > signal06?????? 0?? TINFO?? :?? loop = 23 > signal06?????? 1?? TFAIL?? :?? signal06.c:87: Bug Reproduced! > > But if boot qemu with "-smp 16", the case has great chance to pass. > > > I have two questions about this case: > > 1. I don't know why multi-core will affect the case. Have you looked into the code? The test is trying to reproduce a race condition between two threads of course the number of cores does affect the reproducibility. > 2. On failure situation, what does break the "while loop" shown in below > code. Bug in a kernel that fails to restore fpu state. -- Cyril Hrubis chrubis@suse.cz