[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20201106023547.312639435@goodmis.org>
Date: Thu, 05 Nov 2020 21:32:42 -0500
From: Steven Rostedt (VMware) <rostedt@...dmis.org>
To: linux-kernel@...r.kernel.org
Cc: Masami Hiramatsu <mhiramat@...nel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...nel.org>,
Josh Poimboeuf <jpoimboe@...hat.com>,
Jiri Kosina <jikos@...nel.org>,
Miroslav Benes <mbenes@...e.cz>,
Petr Mladek <pmladek@...e.com>,
Joe Lawrence <joe.lawrence@...hat.com>,
live-patching@...r.kernel.org
Subject: [PATCH 07/11 v3] livepatch: Trigger WARNING if livepatch function fails due to
recursion
From: "Steven Rostedt (VMware)" <rostedt@...dmis.org>
If for some reason a function is called that triggers the recursion
detection of live patching, trigger a warning. By not executing the live
patch code, it is possible that the old unpatched function will be called
placing the system into an unknown state.
Link: https://lore.kernel.org/r/20201029145709.GD16774@alley
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Jiri Kosina <jikos@...nel.org>
Cc: Joe Lawrence <joe.lawrence@...hat.com>
Cc: live-patching@...r.kernel.org
Suggested-by: Miroslav Benes <mbenes@...e.cz>
Reviewed-by: Petr Mladek <pmladek@...e.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@...dmis.org>
---
Changes since v2:
- Blame Miroslav instead of Petr ;-)
kernel/livepatch/patch.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/livepatch/patch.c b/kernel/livepatch/patch.c
index 6c0164d24bbd..15480bf3ce88 100644
--- a/kernel/livepatch/patch.c
+++ b/kernel/livepatch/patch.c
@@ -50,7 +50,7 @@ static void notrace klp_ftrace_handler(unsigned long ip,
ops = container_of(fops, struct klp_ops, fops);
bit = ftrace_test_recursion_trylock();
- if (bit < 0)
+ if (WARN_ON_ONCE(bit < 0))
return;
/*
* A variant of synchronize_rcu() is used to allow patching functions
--
2.28.0
Powered by blists - more mailing lists