From cbf5b73d162b22e044fe0b7d51dcaa33be065253 Mon Sep 17 00:00:00 2001 From: Eiichi Tsukata Date: Thu, 11 Jul 2019 11:35:01 +0900 Subject: [PATCH] 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: 02b67518e2b1 ("tracing: add support for userspace stacktraces in tracing/iter_ctrl") Signed-off-by: Eiichi Tsukata Signed-off-by: Thomas Gleixner Acked-by: Linus Torvalds Link: https://lkml.kernel.org/r/20190711023501.963-1-devel@etsukata.com --- arch/x86/kernel/stacktrace.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/stacktrace.c b/arch/x86/kernel/stacktrace.c index 2abf27d7df6b..4f36d3241faf 100644 --- a/arch/x86/kernel/stacktrace.c +++ b/arch/x86/kernel/stacktrace.c @@ -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 (!consume_entry(cookie, frame.ret_addr, false)) - return; - } - if (fp == frame.next_fp) + if (!frame.ret_addr) + break; + if (!consume_entry(cookie, frame.ret_addr, false)) break; fp = frame.next_fp; }