Commit c2c5d45d authored Dec 31, 2009 by Frederic Weisbecker Committed by Ingo Molnar Jan 13, 2010

perf: Stop stack frame walking off kernel addresses boundaries



While processing kernel perf callchains, an bad entry can be
considered as a valid stack pointer but not as a kernel address.

In this case, we hang in an endless loop. This can happen in an
x86-32 kernel after processing the last entry in a kernel
stacktrace.

Just stop the stack frame walking after we encounter an invalid
kernel address.

This fixes a hard lockup in x86-32.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1262227945-27014-1-git-send-regression-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent 7284ce6c

arch/x86/kernel/dumpstack.c

+8 −6

Original line number	Diff line number	Diff line
		@@ -123,13 +123,15 @@ print_context_stack_bp(struct thread_info *tinfo,
		while (valid_stack_ptr(tinfo, ret_addr, sizeof(*ret_addr), end)) {
		unsigned long addr = *ret_addr;

		if (__kernel_text_address(addr)) {
		if (!__kernel_text_address(addr))
		break;

		ops->address(data, addr, 1);
		frame = frame->next_frame;
		ret_addr = &frame->return_address;
		print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
		}
		}

		return (unsigned long)frame;
		}
		EXPORT_SYMBOL_GPL(print_context_stack_bp);