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x86/dumpstack: Add support for unwinding empty IRQ stacks

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When an interrupt happens in entry code while running on a software IRQ
stack, and the IRQ stack was empty, regs->sp will contain the stack end
address (e.g., irq_stack_ptr).  If the regs are passed to dump_trace(),
get_stack_info() will report STACK_TYPE_UNKNOWN, causing dump_trace() to
return prematurely without trying to go to the next stack.

Update the bounds checking for software interrupt stacks so that the
ending address is now considered part of the stack.

This means that it's now possible for the 'walk_stack' callbacks --
print_context_stack() and print_context_stack_bp() -- to be called with
an empty stack.  But that's fine; they're already prepared to deal with
that due to their on_stack() checks.

Signed-off-by: Josh Poimboeuf <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Byungchul Park <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Nilay Vaish <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/5a5e5de92dcf11e8dc6b6e8e50ad7639d067830b.1473905218.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <[email protected]>
This commit is contained in:
Josh Poimboeuf authored and Ingo Molnar committed 2016-09-15 08:13:15 +02:00
1 parent cb76c93982
commit 5fe599e02e
2 files changed
+15 -3
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arch/x86/kernel/dumpstack_32.c
+10 -2
View File
@@ -35,7 +35,11 @@ static bool in_hardirq_stack(unsigned long *stack, struct stack_info *info)
unsigned long *begin = (unsigned long *)this_cpu_read(hardirq_stack);
unsigned long *end = begin + (THREAD_SIZE / sizeof(long));
if (stack < begin || stack >= end)
/*
* 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)
return false;
info->type = STACK_TYPE_IRQ;
@@ -56,7 +60,11 @@ static bool in_softirq_stack(unsigned long *stack, struct stack_info *info)
unsigned long *begin = (unsigned long *)this_cpu_read(softirq_stack);
unsigned long *end = begin + (THREAD_SIZE / sizeof(long));
if (stack < begin || stack >= end)
/*
* 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)
return false;
info->type = STACK_TYPE_SOFTIRQ;
arch/x86/kernel/dumpstack_64.c
+5 -1
View File
@@ -90,7 +90,11 @@ static bool in_irq_stack(unsigned long *stack, struct stack_info *info)
unsigned long *end = (unsigned long *)this_cpu_read(irq_stack_ptr);
unsigned long *begin = end - (IRQ_STACK_SIZE / sizeof(long));
if (stack < begin || stack >= end)
/*
* 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)
return false;
info->type = STACK_TYPE_IRQ;