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authorChuck Ebbert <76306.1226@compuserve.com>2006-09-25 23:32:19 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-09-26 08:48:55 -0700
commit99325326a57b6a56595bb097655bee9fd27d77b0 (patch)
treec86702f5fdcd8a75ed35c448980d50ae43cd804a /arch/i386
parent1447c27d38faf8fb03d4599e8082e507453ea3cf (diff)
[PATCH] i386: show_registers(): try harder to print failing code
show_registers() tries to dump failing code starting 43 bytes before the offending instruction, but this address can be bad, for example in a device driver where the failing instruction is less than 43 bytes from the start of the driver's code. When that happens, try to dump code starting at the failing instruction instead of printing no code at all. Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> Cc: Andi Kleen <ak@muc.de> Cc: Keith Owens <kaos@ocs.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/i386')
-rw-r--r--arch/i386/kernel/traps.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
index 7e9edafffd8..4fcc6690be9 100644
--- a/arch/i386/kernel/traps.c
+++ b/arch/i386/kernel/traps.c
@@ -313,6 +313,8 @@ void show_registers(struct pt_regs *regs)
*/
if (in_kernel) {
u8 __user *eip;
+ int code_bytes = 64;
+ unsigned char c;
printk("\n" KERN_EMERG "Stack: ");
show_stack_log_lvl(NULL, regs, (unsigned long *)esp, KERN_EMERG);
@@ -320,9 +322,12 @@ void show_registers(struct pt_regs *regs)
printk(KERN_EMERG "Code: ");
eip = (u8 __user *)regs->eip - 43;
- for (i = 0; i < 64; i++, eip++) {
- unsigned char c;
-
+ if (eip < (u8 __user *)PAGE_OFFSET || __get_user(c, eip)) {
+ /* try starting at EIP */
+ eip = (u8 __user *)regs->eip;
+ code_bytes = 32;
+ }
+ for (i = 0; i < code_bytes; i++, eip++) {
if (eip < (u8 __user *)PAGE_OFFSET || __get_user(c, eip)) {
printk(" Bad EIP value.");
break;