From 4cb0e11b15d2badad455fcd538af0cccf05dc012 Mon Sep 17 00:00:00 2001
From: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Date: Tue, 6 Jan 2009 14:42:47 -0800
Subject: [PATCH] coredump_filter: permit changing of the default filter
Introduce a new kernel parameter `coredump_filter'. Setting a value to
this parameter causes the default bitmask of coredump_filter to be
changed.
It is useful for users to change coredump_filter settings for the whole
system at boot time. Without this parameter, users have to change
coredump_filter settings for each /proc/<pid>/ in an initializing script.
Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
Documentation/kernel-parameters.txt | 5 +++++
kernel/fork.c | 15 +++++++++++++--
2 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 3ccf1bc5affe..0b3f6711d2f1 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -551,6 +551,11 @@ and is between 256 and 4096 characters. It is defined in the file
not work reliably with all consoles, but is known
to work with serial and VGA consoles.
+ coredump_filter=
+ [KNL] Change the default value for
+ /proc/<pid>/coredump_filter.
+ See also Documentation/filesystems/proc.txt.
+
cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
Format:
<first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
diff --git a/kernel/fork.c b/kernel/fork.c
index 23b912116675..7b8f2a78be3d 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -400,6 +400,18 @@ __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock);
#define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL))
#define free_mm(mm) (kmem_cache_free(mm_cachep, (mm)))
+static unsigned long default_dump_filter = MMF_DUMP_FILTER_DEFAULT;
+
+static int __init coredump_filter_setup(char *s)
+{
+ default_dump_filter =
+ (simple_strtoul(s, NULL, 0) << MMF_DUMP_FILTER_SHIFT) &
+ MMF_DUMP_FILTER_MASK;
+ return 1;
+}
+
+__setup("coredump_filter=", coredump_filter_setup);
+
#include <linux/init_task.h>
static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p)
@@ -408,8 +420,7 @@ static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p)
atomic_set(&mm->mm_count, 1);
init_rwsem(&mm->mmap_sem);
INIT_LIST_HEAD(&mm->mmlist);
- mm->flags = (current->mm) ? current->mm->flags
- : MMF_DUMP_FILTER_DEFAULT;
+ mm->flags = (current->mm) ? current->mm->flags : default_dump_filter;
mm->core_state = NULL;
mm->nr_ptes = 0;
set_mm_counter(mm, file_rss, 0);
--
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