From: Oleg Nesterov <oleg@redhat.com>
To: Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Puranjay Mohan <puranjay@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Mark Brown <broonie@kernel.org>,
Kalesh Singh <kaleshsingh@google.com>,
chenqiwu <qiwuchen55@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: arm64: stacktrace: WARN_ON(state->common.pc == orig_pc) in kunwind_recover_return_address()
Date: Mon, 16 Sep 2024 12:27:41 +0200 [thread overview]
Message-ID: <20240916102741.GA13899@redhat.com> (raw)
I don't know the details but people report that
kunwind_recover_return_address() hits this warning.
I know absolutely nothing about arm64 or kernel/trace/fgraph.c, but at
first glance this code looks broken:
kunwind_recover_return_address:
...
orig_pc = ftrace_graph_ret_addr(state->task, NULL,
state->common.pc,
(void *)state->common.fp);
if (WARN_ON_ONCE(state->common.pc == orig_pc))
ftrace_graph_ret_addr:
...
if (!idx)
return ret;
given that kunwind_recover_return_address() passes idx == NULL to
ftrace_graph_ret_addr(), it should always return ret == state->common.pc ?
Perhaps this connects to 29c1c24a27 ("function_graph: Fix up ftrace_graph_ret_addr()")
and I have no idea if something like the patch below makes any sense.
Oleg.
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -106,7 +106,8 @@ kunwind_recover_return_address(struct kunwind_state *state)
if (state->task->ret_stack &&
(state->common.pc == (unsigned long)return_to_handler)) {
unsigned long orig_pc;
- orig_pc = ftrace_graph_ret_addr(state->task, NULL,
+ orig_pc = ftrace_graph_ret_addr(state->task,
+ &state->task->curr_ret_stack,
state->common.pc,
(void *)state->common.fp);
if (WARN_ON_ONCE(state->common.pc == orig_pc))
next reply other threads:[~2024-09-16 10:29 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-16 10:27 Oleg Nesterov [this message]
2024-09-16 10:37 ` arm64: stacktrace: WARN_ON(state->common.pc == orig_pc) in kunwind_recover_return_address() Puranjay Mohan
2024-09-16 14:18 ` Oleg Nesterov
2024-09-16 10:38 ` Oleg Nesterov
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