[PATCH] i386: add option to show more code in oops reports
Sometimes developers need to see more object code in an oops report,
e.g. when kernel may be corrupted at runtime.
Add the "code_bytes" option for this.
Signed-off-by: Chuck Ebbert <cebbert@redhat.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 733a736..22b1996 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -364,6 +364,11 @@
clocksource is not available, it defaults to PIT.
Format: { pit | tsc | cyclone | pmtmr }
+ code_bytes [IA32] How many bytes of object code to print in an
+ oops report.
+ Range: 0 - 8192
+ Default: 64
+
disable_8254_timer
enable_8254_timer
[IA32/X86_64] Disable/Enable interrupt 0 timer routing
diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
index 4ec2103..af0d3f7 100644
--- a/arch/i386/kernel/traps.c
+++ b/arch/i386/kernel/traps.c
@@ -94,6 +94,7 @@
asmlinkage void machine_check(void);
int kstack_depth_to_print = 24;
+static unsigned int code_bytes = 64;
ATOMIC_NOTIFIER_HEAD(i386die_chain);
int register_die_notifier(struct notifier_block *nb)
@@ -325,7 +326,8 @@
*/
if (in_kernel) {
u8 *eip;
- int code_bytes = 64;
+ unsigned int code_prologue = code_bytes * 43 / 64;
+ unsigned int code_len = code_bytes;
unsigned char c;
printk("\n" KERN_EMERG "Stack: ");
@@ -333,14 +335,14 @@
printk(KERN_EMERG "Code: ");
- eip = (u8 *)regs->eip - 43;
+ eip = (u8 *)regs->eip - code_prologue;
if (eip < (u8 *)PAGE_OFFSET ||
probe_kernel_address(eip, c)) {
/* try starting at EIP */
eip = (u8 *)regs->eip;
- code_bytes = 32;
+ code_len = code_len - code_prologue + 1;
}
- for (i = 0; i < code_bytes; i++, eip++) {
+ for (i = 0; i < code_len; i++, eip++) {
if (eip < (u8 *)PAGE_OFFSET ||
probe_kernel_address(eip, c)) {
printk(" Bad EIP value.");
@@ -1192,3 +1194,13 @@
return 1;
}
__setup("kstack=", kstack_setup);
+
+static int __init code_bytes_setup(char *s)
+{
+ code_bytes = simple_strtoul(s, NULL, 0);
+ if (code_bytes > 8192)
+ code_bytes = 8192;
+
+ return 1;
+}
+__setup("code_bytes=", code_bytes_setup);