From: Chuck Ebbert <76306.1226@compuserve.com> 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 --- arch/i386/kernel/traps.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff -puN arch/i386/kernel/traps.c~i386-show_registers-try-harder-to-print-failing arch/i386/kernel/traps.c --- a/arch/i386/kernel/traps.c~i386-show_registers-try-harder-to-print-failing +++ a/arch/i386/kernel/traps.c @@ -318,6 +318,8 @@ 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); @@ -325,9 +327,12 @@ 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; _