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From:   Ze Gao <zegao2021@gmail.com>
To:     Steven Rostedt <rostedt@goodmis.org>,
        Masami Hiramatsu <mhiramat@kernel.org>
Cc:     Ze Gao <zegao@tencent.com>, linux-kernel@vger.kernel.org,
        linux-trace-kernel@vger.kernel.org
Subject: [PATCH 1/4] rethook: use preempt_{disable, enable}_notrace in rethook_trampoline_handler
Date:   Mon, 15 May 2023 11:26:38 +0800
Message-Id: <a17a14abfb81cb0eea77c2ee10d7fc98d5d5a73e.1684120990.git.zegao@tencent.com>
In-Reply-To: <cover.1684120990.git.zegao@tencent.com>
References: <cover.1684120990.git.zegao@tencent.com>
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This patch replace preempt_{disable, enable} with its corresponding
notrace version in rethook_trampoline_handler so no worries about stack
recursion or overflow introduced by preempt_count_{add, sub} under
fprobe + rethook context.

Signed-off-by: Ze Gao <zegao@tencent.com>
---
 kernel/trace/rethook.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/rethook.c b/kernel/trace/rethook.c
index 32c3dfdb4d6a..60f6cb2b486b 100644
--- a/kernel/trace/rethook.c
+++ b/kernel/trace/rethook.c
@@ -288,7 +288,7 @@ unsigned long rethook_trampoline_handler(struct pt_regs *regs,
 	 * These loops must be protected from rethook_free_rcu() because those
 	 * are accessing 'rhn->rethook'.
 	 */
-	preempt_disable();
+	preempt_disable_notrace();
 
 	/*
 	 * Run the handler on the shadow stack. Do not unlink the list here because
@@ -321,7 +321,7 @@ unsigned long rethook_trampoline_handler(struct pt_regs *regs,
 		first = first->next;
 		rethook_recycle(rhn);
 	}
-	preempt_enable();
+	preempt_enable_notrace();
 
 	return correct_ret_addr;
 }
-- 
2.40.1