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Commit 0d2b8579 authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Ingo Molnar
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x86/dumpstack: Warn on stack recursion 



Print a warning if stack recursion is detected.

Use printk_deferred_once() because the unwinder can be called with the
console lock by lockdep via save_stack_trace().

Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/def18247aafaab480844484398e793f552b79bda.1477496147.git.jpoimboe@redhat.com


[ Unbroke the lines. ]
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent c32c47c6

arch/x86/kernel/dumpstack_32.c

+3 −1
Original line number Diff line number Diff line
@@ -109,8 +109,10 @@ int get_stack_info(unsigned long *stack, struct task_struct *task, 
	 * just break out and report an unknown stack type.

	 */

	if (visit_mask) {

		if (*visit_mask & (1UL << info->type))

		if (*visit_mask & (1UL << info->type)) {

			printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type);

			goto unknown;

		}

		*visit_mask |= 1UL << info->type;

	}

arch/x86/kernel/dumpstack_64.c

+3 −1
Original line number Diff line number Diff line
@@ -128,8 +128,10 @@ int get_stack_info(unsigned long *stack, struct task_struct *task, 
	 * just break out and report an unknown stack type.

	 */

	if (visit_mask) {

		if (*visit_mask & (1UL << info->type))

		if (*visit_mask & (1UL << info->type)) {

			printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type);

			goto unknown;

		}

		*visit_mask |= 1UL << info->type;

	}