From 99325326a57b6a56595bb097655bee9fd27d77b0 Mon Sep 17 00:00:00 2001 From: Chuck Ebbert <76306.1226@compuserve.com> Date: Mon, 25 Sep 2006 23:32:19 -0700 Subject: [PATCH] [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 Cc: Keith Owens Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/i386/kernel/traps.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c index 7e9edafffd8a..4fcc6690be99 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;