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From:   Ze Gao <zegao2021@gmail.com>
To:     Masami Hiramatsu <mhiramat@kernel.org>
Cc:     Steven Rostedt <rostedt@goodmis.org>, Ze Gao <zegao2021@gmail.com>,
        linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
        Ze Gao <zegao@tencent.com>, Yafang <laoar.shao@gmail.com>
Subject: [PATCH v2] fprobe: add unlock to match a succeeded ftrace_test_recursion_trylock
Date:   Mon,  3 Jul 2023 17:23:36 +0800
Message-Id: <20230703092336.268371-1-zegao@tencent.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Unlock ftrace recursion lock when fprobe_kprobe_handler() is failed
because of some running kprobe.

Fixes: 3cc4e2c5fbae ("fprobe: make fprobe_kprobe_handler recursion free")
Reported-by: Yafang <laoar.shao@gmail.com>
Closes: https://lore.kernel.org/linux-trace-kernel/CALOAHbC6UpfFOOibdDiC7xFc5YFUgZnk3MZ=3Ny6we=AcrNbew@mail.gmail.com/
Signed-off-by: Ze Gao <zegao@tencent.com>
---
 kernel/trace/fprobe.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index 18d36842faf5..93b3e361bb97 100644
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@ -102,12 +102,14 @@ static void fprobe_kprobe_handler(unsigned long ip, unsigned long parent_ip,
 
 	if (unlikely(kprobe_running())) {
 		fp->nmissed++;
-		return;
+		goto recursion_unlock;
 	}
 
 	kprobe_busy_begin();
 	__fprobe_handler(ip, parent_ip, ops, fregs);
 	kprobe_busy_end();
+
+recursion_unlock:
 	ftrace_test_recursion_unlock(bit);
 }
 
-- 
2.40.1