Commit fa332154 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Borislav Petkov
Browse files

x86/dumpstack: Fix off-by-one errors in stack identification 



The get_stack_info() function is off-by-one when checking whether an
address is on a IRQ stack or a IST stack. This prevents an overflowed
IRQ or IST stack from being dumped properly.

[ tglx: Do the same for 32-bit ]

Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Reviewed-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190414160143.785651055@linutronix.de
parent 7dbcf2b0

arch/x86/kernel/dumpstack_32.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -41,7 +41,7 @@ static bool in_hardirq_stack(unsigned long *stack, struct stack_info *info) 
	 * This is a software stack, so 'end' can be a valid stack pointer.

	 * This is a software stack, so 'end' can be a valid stack pointer.

	 * It just means the stack is empty.

	 * It just means the stack is empty.

	 */

	 */

	if (stack <= begin || stack > end)

	if (stack < begin || stack > end)

		return false;

		return false;





	info->type	= STACK_TYPE_IRQ;

	info->type	= STACK_TYPE_IRQ;
@@ -66,7 +66,7 @@ static bool in_softirq_stack(unsigned long *stack, struct stack_info *info) 
	 * This is a software stack, so 'end' can be a valid stack pointer.

	 * This is a software stack, so 'end' can be a valid stack pointer.

	 * It just means the stack is empty.

	 * It just means the stack is empty.

	 */

	 */

	if (stack <= begin || stack > end)

	if (stack < begin || stack > end)

		return false;

		return false;





	info->type	= STACK_TYPE_SOFTIRQ;

	info->type	= STACK_TYPE_SOFTIRQ;

arch/x86/kernel/dumpstack_64.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -65,7 +65,7 @@ static bool in_exception_stack(unsigned long *stack, struct stack_info *info) 
		begin = end - (exception_stack_sizes[k] / sizeof(long));

		begin = end - (exception_stack_sizes[k] / sizeof(long));

		regs  = (struct pt_regs *)end - 1;

		regs  = (struct pt_regs *)end - 1;





		if (stack <= begin || stack >= end)

		if (stack < begin || stack >= end)

			continue;

			continue;





		info->type	= STACK_TYPE_EXCEPTION + k;

		info->type	= STACK_TYPE_EXCEPTION + k;
@@ -88,7 +88,7 @@ static bool in_irq_stack(unsigned long *stack, struct stack_info *info) 
	 * This is a software stack, so 'end' can be a valid stack pointer.

	 * This is a software stack, so 'end' can be a valid stack pointer.

	 * It just means the stack is empty.

	 * It just means the stack is empty.

	 */

	 */

	if (stack <= begin || stack > end)

	if (stack < begin || stack >= end)

		return false;

		return false;





	info->type	= STACK_TYPE_IRQ;

	info->type	= STACK_TYPE_IRQ;

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