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Commit a343c75d authored by H. Peter Anvin's avatar H. Peter Anvin
Browse files

x86: use kernel_stack_pointer() in dumpstack.c 



The way to obtain a kernel-mode stack pointer from a struct pt_regs in
32-bit mode is "subtle": the stack doesn't actually contain the stack
pointer, but rather the location where it would have been marks the
actual previous stack frame.  For clarity, use kernel_stack_pointer()
instead of coding this weirdness explicitly.

Furthermore, user_mode() is only valid when the process is known to
not run in V86 mode.  Use the safer user_mode_vm() instead.

Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent def3c5d0

arch/x86/kernel/dumpstack.c

+4 −3
Original line number Diff line number Diff line
@@ -268,11 +268,12 @@ int __kprobes __die(const char *str, struct pt_regs *regs, long err) 


	show_registers(regs);

#ifdef CONFIG_X86_32

	sp = (unsigned long) (&regs->sp);

	savesegment(ss, ss);

	if (user_mode(regs)) {

	if (user_mode_vm(regs)) {

		sp = regs->sp;

		ss = regs->ss & 0xffff;

	} else {

		sp = kernel_stack_pointer(regs);

		savesegment(ss, ss);

	}

	printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);

	print_symbol("%s", regs->ip);