linux-kernel - [PATCH] rethook: use preempt_{disable, enable}_notrace in rethook_trampoline

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Date:   Sat, 13 May 2023 16:23:46 +0800
From:   Ze Gao <zegao2021@...il.com>
To:     Steven Rostedt <rostedt@...dmis.org>,
        Masami Hiramatsu <mhiramat@...nel.org>
Cc:     Ze Gao <zegao@...cent.com>, linux-kernel@...r.kernel.org,
        linux-trace-kernel@...r.kernel.org
Subject: [PATCH] rethook: use preempt_{disable, enable}_notrace in rethook_trampoline_handler

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@...cent.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