----- Original Message ----- > From: "Wanlong Gao" <gaowanl...@cn.fujitsu.com> > To: "Jan Stancek" <jstan...@redhat.com>, "Xiaoguang Wang" > <wangxg.f...@cn.fujitsu.com> > Cc: ltp-list@lists.sourceforge.net, "Artem Savkov" <asav...@redhat.com> > Sent: Monday, 21 July, 2014 11:09:47 AM > Subject: Re: [LTP] [PATCH 2/2] syscalls/getcwd04.c: regression test for > getcwd(2) > > On 07/21/2014 05:04 PM, Jan Stancek wrote: > > > > > > ----- Original Message ----- > >> > From: "Xiaoguang Wang" <wangxg.f...@cn.fujitsu.com> > >> > To: ltp-list@lists.sourceforge.net > >> > Sent: Tuesday, 15 July, 2014 12:13:49 PM > >> > Subject: [LTP] [PATCH 2/2] syscalls/getcwd04.c: regression test for > >> > getcwd(2) > >> > > >> > Note: this test has already been in xfstests generic/028 test case, > >> > I just port it to LTP. > >> > > >> > Kernel commit '232d2d60aa5469bb097f55728f65146bd49c1d25' introduced a > >> > race > >> > condition that causes getcwd(2) to return "/" instead of correct path. > >> > 232d2d6 dcache: Translating dentry into pathname without > >> > taking rename_lock > >> > > >> > And these two kernel commits have fixed this bug: > >> > ede4cebce16f5643c61aedd6d88d9070a1d23a68 > >> > prepend_path() needs to reinitialize dentry/vfsmount/mnt on > >> > restarts > >> > f6500801522c61782d4990fa1ad96154cb397cd4 > >> > f650080 __dentry_path() fixes > >> > > >> > This test is to check whether this bug exists in the running kernel, > >> > or whether this bug has been fixed. > >> > > >> > Signed-off-by: Xiaoguang Wang <wangxg.f...@cn.fujitsu.com> > > Hi, > > > > looks good to me. > > > >> > I have run this test case in RHEL7.0GA, Fedora19, v3.11-7758-g232d2d6 > >> > and 3.16.0-rc4+. > >> > RHEL7.0GA has this kernel bug, so this test case fails. > > I can confirm this, with note that I've seen it happen only on systems with > > 2+ CPUs. > > If this note is truth, we should judge the nr_cpus in this case to make sure > it always > gives the right result.
My observation is that it's at least easier to reproduce on 2+ CPUs: # time taskset -c 0 ./getcwd04 getcwd04 1 TPASS : Bug is not reproduced! real 0m5.002s user 0m0.506s sys 0m4.494s # time taskset -c 0,1 ./getcwd04 getcwd04 1 TFAIL : initial current work directory is /tmp/getg6foNN/testdir, now is /. Bug is reproduced! real 0m0.002s user 0m0.000s sys 0m0.002s I'm not sure what you are suggesting we do, other than to make note somewhere. It's a test for race condition, so if it tried its best to reproduce and ended with "Bug is not reproduced!", that looks like right result to me. Regards, Jan > > Thanks, > Wanlong Gao > > > ------------------------------------------------------------------------------ Want fast and easy access to all the code in your enterprise? Index and search up to 200,000 lines of code with a free copy of Black Duck Code Sight - the same software that powers the world's largest code search on Ohloh, the Black Duck Open Hub! Try it now. http://p.sf.net/sfu/bds _______________________________________________ Ltp-list mailing list Ltp-list@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/ltp-list
