[patch V3 03/32] x86/dumpstack: Fix off-by-one errors in stack identification

Thomas Gleixner
2019-04-14T16:02:22Z

From: Andy Lutomirski <luto@kernel.org>

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 a overflowed IRQ
or IST stack from being dumped properly.

[ tglx: Do the same for 32-bit ]

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>

---
arch/x86/kernel/dumpstack_32.c | 4 ++--
arch/x86/kernel/dumpstack_64.c | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)

--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -41,7 +41,7 @@ static bool in_hardirq_stack(unsigned lo
* This is a software stack, so 'end' can be a valid stack pointer.
* It just means the stack is empty.
*/
- if (stack <= begin || stack > end)
+ if (stack < begin || stack > end)
return false;

info->type = STACK_TYPE_IRQ;
@@ -66,7 +66,7 @@ static bool in_softirq_stack(unsigned lo
* This is a software stack, so 'end' can be a valid stack pointer.
* It just means the stack is empty.
*/
- if (stack <= begin || stack > end)
+ if (stack < begin || stack > end)
return false;

info->type = STACK_TYPE_SOFTIRQ;
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -65,7 +65,7 @@ static bool in_exception_stack(unsigned
begin = end - (exception_stack_sizes[k] / sizeof(long));
regs = (struct pt_regs *)end - 1;

- if (stack <= begin || stack >= end)
+ if (stack < begin || stack >= end)
continue;

info->type = STACK_TYPE_EXCEPTION + k;
@@ -88,7 +88,7 @@ static bool in_irq_stack(unsigned long *
* This is a software stack, so 'end' can be a valid stack pointer.
* It just means the stack is empty.
*/
- if (stack <= begin || stack > end)
+ if (stack < begin || stack >= end)
return false;

info->type = STACK_TYPE_IRQ;