From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Fri, 26 Jun 2020 10:00:01 +0100 From: Christoph Hellwig Subject: Re: linux-next: umh: fix processed error when UMH_WAIT_PROC is used seems to break linux bridge on s390x (bisected) Message-ID: <20200626090001.GA30103@infradead.org> References: <3118dc0d-a3af-9337-c897-2380062a8644@de.ibm.com> <20200624144311.GA5839@infradead.org> <9e767819-9bbe-2181-521e-4d8ca28ca4f7@de.ibm.com> <20200624160953.GH4332@42.do-not-panic.com> <4e27098e-ac8d-98f0-3a9a-ea25242e24ec@de.ibm.com> <4d8fbcea-a892-3453-091f-d57c03f9aa90@de.ibm.com> <1263e370-7cee-24d8-b98c-117bf7c90a83@de.ibm.com> <20200626025410.GJ4332@42.do-not-panic.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: To: Christian Borntraeger Cc: Luis Chamberlain , Christoph Hellwig , ast@kernel.org, axboe@kernel.dk, bfields@fieldses.org, bridge@lists.linux-foundation.org, chainsaw@gentoo.org, christian.brauner@ubuntu.com, chuck.lever@oracle.com, davem@davemloft.net, dhowells@redhat.com, gregkh@linuxfoundation.org, jarkko.sakkinen@linux.intel.com, jmorris@namei.org, josh@joshtriplett.org, keescook@chromium.org, keyrings@vger.kernel.org, kuba@kernel.org, lars.ellenberg@linbit.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-security-module@vger.kernel.org, nikolay@cumulusnetworks.com, philipp.reisner@linbit.com, ravenexp@gmail.com, roopa@cumulusnetworks.com, serge@hallyn.com, slyfox@gentoo.org, viro@zeniv.linux.org.uk, yangtiezhu@loongson.cn, netdev@vger.kernel.org, markward@linux.ibm.com, linux-s390 On Fri, Jun 26, 2020 at 07:22:34AM +0200, Christian Borntraeger wrote: > > > On 26.06.20 04:54, Luis Chamberlain wrote: > > On Wed, Jun 24, 2020 at 08:37:55PM +0200, Christian Borntraeger wrote: > >> > >> > >> On 24.06.20 20:32, Christian Borntraeger wrote: > >> [...]> > >>> So the translations look correct. But your change is actually a sematic change > >>> if(ret) will only trigger if there is an error > >>> if (KWIFEXITED(ret)) will always trigger when the process ends. So we will always overwrite -ECHILD > >>> and we did not do it before. > >>> > >> > >> So the right fix is > >> > >> diff --git a/kernel/umh.c b/kernel/umh.c > >> index f81e8698e36e..a3a3196e84d1 100644 > >> --- a/kernel/umh.c > >> +++ b/kernel/umh.c > >> @@ -154,7 +154,7 @@ static void call_usermodehelper_exec_sync(struct subprocess_info *sub_info) > >> * the real error code is already in sub_info->retval or > >> * sub_info->retval is 0 anyway, so don't mess with it then. > >> */ > >> - if (KWIFEXITED(ret)) > >> + if (KWEXITSTATUS(ret)) > >> sub_info->retval = KWEXITSTATUS(ret); > >> } > >> > >> I think. > > > > Nope, the right form is to check for WIFEXITED() before using WEXITSTATUS(). > > But this IS a change over the previous code, no? > I will test next week as I am travelling right now. I'm all for reverting back to the previous behavior. If someone wants a behavior change it should be a separate patch. And out of pure self interest I'd like to see that change after my addition of the kernel_wait helper to replace the kernel_wait4 abuse :)