Commit cbf5b73d authored Jul 11, 2019 by Eiichi Tsukata Committed by Thomas Gleixner Jul 11, 2019

x86/stacktrace: Prevent infinite loop in arch_stack_walk_user()

arch_stack_walk_user() checks `if (fp == frame.next_fp)` to prevent a
infinite loop by self reference but it's not enogh for circular reference.

Once a lack of return address is found, there is no point to continue the
loop, so break out.

Fixes: 02b67518 ("tracing: add support for userspace stacktraces in tracing/iter_ctrl")
Signed-off-by: Eiichi Tsukata <devel@etsukata.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lkml.kernel.org/r/20190711023501.963-1-devel@etsukata.com

parent 7652ac92

arch/x86/kernel/stacktrace.c

+3 −5

Original line number	Diff line number	Diff line
		@@ -129,11 +129,9 @@ void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,
		break;
		if ((unsigned long)fp < regs->sp)
		break;
		if (frame.ret_addr) {
		if (!frame.ret_addr)
		break;
		if (!consume_entry(cookie, frame.ret_addr, false))
		return;
		}
		if (fp == frame.next_fp)
		break;
		fp = frame.next_fp;
		}