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authorNeil Horman <nhorman@tuxdriver.com>2009-04-02 19:58:57 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-04-02 22:05:04 -0400
commit04d491ab2a53008a1aa98ac09561768c7f3adda3 (patch)
treeab8fff6fb8674c8061b733ce64d6d6fba9d68ff3 /kernel
parent23c36c1aec895fd52d7dd8cd3ce4bbce43c969fd (diff)
kexec: add dmesg log symbols to /proc/vmcoreinfo lists
It would be nice to be able to extract the dmesg log from a vmcore file without needing to keep the debug symbols for the running kernel handy all the time. We have a facility to do this in /proc/vmcore. This patch adds the log_buf and log_end symbols to the vmcoreinfo area so that tools (like makedumpfile) can easily extract the dmesg logs from a vmcore image. [akpm@linux-foundation.org: several fixes and cleanups] [akpm@linux-foundation.org: fix unused log_buf_kexec_setup()] [akpm@linux-foundation.org: build fix] Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Cc: Simon Horman <horms@verge.net.au> Acked-by: Vivek Goyal <vgoyal@redhat.com> Cc: Neil Horman <nhorman@tuxdriver.com> Cc: Simon Horman <horms@verge.net.au> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/kexec.c1
-rw-r--r--kernel/printk.c19
2 files changed, 20 insertions, 0 deletions
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 93eed85fe017..589832aac41f 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -1409,6 +1409,7 @@ static int __init crash_save_vmcoreinfo_init(void)
1409 VMCOREINFO_OFFSET(list_head, prev); 1409 VMCOREINFO_OFFSET(list_head, prev);
1410 VMCOREINFO_OFFSET(vm_struct, addr); 1410 VMCOREINFO_OFFSET(vm_struct, addr);
1411 VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER); 1411 VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER);
1412 log_buf_kexec_setup();
1412 VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES); 1413 VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES);
1413 VMCOREINFO_NUMBER(NR_FREE_PAGES); 1414 VMCOREINFO_NUMBER(NR_FREE_PAGES);
1414 VMCOREINFO_NUMBER(PG_lru); 1415 VMCOREINFO_NUMBER(PG_lru);
diff --git a/kernel/printk.c b/kernel/printk.c
index e3602d0755b0..a5f61a9acedb 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -32,6 +32,7 @@
32#include <linux/security.h> 32#include <linux/security.h>
33#include <linux/bootmem.h> 33#include <linux/bootmem.h>
34#include <linux/syscalls.h> 34#include <linux/syscalls.h>
35#include <linux/kexec.h>
35 36
36#include <asm/uaccess.h> 37#include <asm/uaccess.h>
37 38
@@ -135,6 +136,24 @@ static char *log_buf = __log_buf;
135static int log_buf_len = __LOG_BUF_LEN; 136static int log_buf_len = __LOG_BUF_LEN;
136static unsigned logged_chars; /* Number of chars produced since last read+clear operation */ 137static unsigned logged_chars; /* Number of chars produced since last read+clear operation */
137 138
139#ifdef CONFIG_KEXEC
140/*
141 * This appends the listed symbols to /proc/vmcoreinfo
142 *
143 * /proc/vmcoreinfo is used by various utiilties, like crash and makedumpfile to
144 * obtain access to symbols that are otherwise very difficult to locate. These
145 * symbols are specifically used so that utilities can access and extract the
146 * dmesg log from a vmcore file after a crash.
147 */
148void log_buf_kexec_setup(void)
149{
150 VMCOREINFO_SYMBOL(log_buf);
151 VMCOREINFO_SYMBOL(log_end);
152 VMCOREINFO_SYMBOL(log_buf_len);
153 VMCOREINFO_SYMBOL(logged_chars);
154}
155#endif
156
138static int __init log_buf_len_setup(char *str) 157static int __init log_buf_len_setup(char *str)
139{ 158{
140 unsigned size = memparse(str, &str); 159 unsigned size = memparse(str, &str);