Messages in this thread Patch in this message | | | Date | Fri, 29 Aug 2008 15:22:15 -0400 | From | "La Monte H.P. Yarroll" <> | Subject | [PATCH] Provide control over core name even for multithreaded processes |
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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 .<tid> for multithreaded processes.
The attached patch introduces "%T" to the core_pattern language, which expands to ".<tid>" 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 <piggy@laurelnetworks.com> 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 %<OTHER> 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;
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