From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754705AbYIBWPU (ORCPT ); Tue, 2 Sep 2008 18:15:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753381AbYIBWPI (ORCPT ); Tue, 2 Sep 2008 18:15:08 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:36336 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753189AbYIBWPG (ORCPT ); Tue, 2 Sep 2008 18:15:06 -0400 Date: Tue, 2 Sep 2008 15:14:26 -0700 From: Andrew Morton To: "La Monte H.P. Yarroll" Cc: linux-kernel@vger.kernel.org, Oleg Nesterov Subject: Re: [PATCH] Provide control over core name even for multithreaded processes Message-Id: <20080902151426.98935cd1.akpm@linux-foundation.org> In-Reply-To: <20080829152215.2cdb1438@kartuli> References: <20080829152215.2cdb1438@kartuli> X-Mailer: Sylpheed version 2.2.4 (GTK+ 2.8.20; i486-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 29 Aug 2008 15:22:15 -0400 "La Monte H.P. Yarroll" wrote: > Our system explicitly sets core_pattern to force a relatively small > limit on the number of different core dump names. > > Unfortunately, the kernel unconditionally appends . for > multithreaded processes. > > The attached patch introduces "%T" to the core_pattern language, which > expands to "." for multithreaded processes. It then changes the > default core_pattern to "core%T" replicating the current default > behavior. > > Signed-off-by: La Monte H.P. Yarroll 74-256740 > > diff -Naur linux-2.6.26.3/Documentation/sysctl/kernel.txt linux-2.6.26.3-new/Documentation/sysctl/kernel.txt > --- linux-2.6.26.3/Documentation/sysctl/kernel.txt 2008-08-20 14:11:37.000000000 -0400 > +++ linux-2.6.26.3-new/Documentation/sysctl/kernel.txt 2008-08-28 13:27:50.239325000 -0400 > @@ -88,7 +88,7 @@ > core_pattern: > > core_pattern is used to specify a core dumpfile pattern name. > -. max length 128 characters; default value is "core" > +. max length 128 characters; default value is "core%T" > . core_pattern is used as a pattern template for the output filename; > certain string patterns (beginning with '%') are substituted with > their actual values. > @@ -104,6 +104,7 @@ > %g gid > %s signal number > %t UNIX time of dump > + %T .tgid or nothing if process is not threaded > %h hostname > %e executable filename > % both are dropped > diff -Naur linux-2.6.26.3/fs/exec.c linux-2.6.26.3-new/fs/exec.c > --- linux-2.6.26.3/fs/exec.c 2008-08-20 14:11:37.000000000 -0400 > +++ linux-2.6.26.3-new/fs/exec.c 2008-08-28 13:46:57.919768000 -0400 > @@ -66,7 +66,7 @@ > #endif > > int core_uses_pid; > -char core_pattern[CORENAME_MAX_SIZE] = "core"; > +char core_pattern[CORENAME_MAX_SIZE] = "core%T"; > int suid_dumpable = 0; > > /* The maximal length of core_pattern is also specified in sysctl.c */ > @@ -1415,7 +1415,7 @@ > case 'p': > pid_in_pattern = 1; > rc = snprintf(out_ptr, out_end - out_ptr, > - "%d", task_tgid_vnr(current)); > + "%d", task_pid_vnr(current)); > if (rc > out_end - out_ptr) > goto out; > out_ptr += rc; > @@ -1455,6 +1455,17 @@ > out_ptr += rc; > break; > } > + /* Conditional tgid */ > + case 'T': { > + if (atomic_read(¤t->mm->mm_users) != 1) { > + rc = snprintf(out_ptr, out_end - out_ptr, > + ".%d", task_tgid_vnr(current)); > + if (rc > out_end - out_ptr) > + goto out; > + out_ptr += rc; > + } > + break; > + } > /* hostname */ > case 'h': > down_read(&uts_sem); > @@ -1492,10 +1503,9 @@ > * If core_pattern does not include a %p (as is the default) > * and core_uses_pid is set, then .%pid will be appended to > * the filename. Do not do this for piped commands. */ > - if (!ispipe && !pid_in_pattern > - && (core_uses_pid || atomic_read(¤t->mm->mm_users) != 1)) { > + if (!ispipe && !pid_in_pattern && core_uses_pid) { > rc = snprintf(out_ptr, out_end - out_ptr, > - ".%d", task_tgid_vnr(current)); > + ".%d", current->pid); > if (rc > out_end - out_ptr) > goto out; > out_ptr += rc; Please review Oleg's http://userweb.kernel.org/~akpm/mmotm/broken-out/coredump-format_corename-dont-append-%25pid-if-multi-threaded.patch, which I have queued for 2.6.28.