diff mbox series

[v3,26/28] kprobes: Use RCU in all users of __module_text_address().

Message ID 20250108090457.512198-27-bigeasy@linutronix.de (mailing list archive)
State New
Headers show
Series None | expand

Commit Message

Sebastian Andrzej Siewior Jan. 8, 2025, 9:04 a.m. UTC
__module_text_address() can be invoked within a RCU section, there is no
requirement to have preemption disabled.

Replace the preempt_disable() section around __module_text_address()
with RCU.

Cc: David S. Miller <davem@davemloft.net>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Naveen N Rao <naveen@kernel.org>
Cc: linux-trace-kernel@vger.kernel.org
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 kernel/kprobes.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Masami Hiramatsu (Google) Jan. 28, 2025, 5:44 a.m. UTC | #1
On Wed,  8 Jan 2025 10:04:55 +0100
Sebastian Andrzej Siewior <bigeasy@linutronix.de> wrote:

> __module_text_address() can be invoked within a RCU section, there is no
> requirement to have preemption disabled.
> 
> Replace the preempt_disable() section around __module_text_address()
> with RCU.

Hi,

Since the below cleanup has been merged, this patch needs to be updated.

https://lore.kernel.org/all/20241121-kprobes-preempt-v1-1-fd581ee7fcbb@linutronix.de/

(may need to change the guard(preempt)() -> guard(rcu)() in the new version.)

Thank you,

> 
> Cc: David S. Miller <davem@davemloft.net>
> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
> Cc: Masami Hiramatsu <mhiramat@kernel.org>
> Cc: Naveen N Rao <naveen@kernel.org>
> Cc: linux-trace-kernel@vger.kernel.org
> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> ---
>  kernel/kprobes.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index b027a4030976a..22e47a27df4aa 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -1566,7 +1566,7 @@ static int check_kprobe_address_safe(struct kprobe *p,
>  	if (ret)
>  		return ret;
>  	jump_label_lock();
> -	preempt_disable();
> +	rcu_read_lock();
>  
>  	/* Ensure the address is in a text area, and find a module if exists. */
>  	*probed_mod = NULL;
> @@ -1612,7 +1612,7 @@ static int check_kprobe_address_safe(struct kprobe *p,
>  	}
>  
>  out:
> -	preempt_enable();
> +	rcu_read_unlock();
>  	jump_label_unlock();
>  
>  	return ret;
> -- 
> 2.47.1
>
Sebastian Andrzej Siewior Jan. 28, 2025, 7:10 a.m. UTC | #2
On 2025-01-28 14:44:52 [+0900], Masami Hiramatsu wrote:
> Hi,

Hi,

> Since the below cleanup has been merged, this patch needs to be updated.
> 
> https://lore.kernel.org/all/20241121-kprobes-preempt-v1-1-fd581ee7fcbb@linutronix.de/
> 
> (may need to change the guard(preempt)() -> guard(rcu)() in the new version.)

Thanks, I'm on it.

> Thank you,

Sebastian
diff mbox series

Patch

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index b027a4030976a..22e47a27df4aa 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1566,7 +1566,7 @@  static int check_kprobe_address_safe(struct kprobe *p,
 	if (ret)
 		return ret;
 	jump_label_lock();
-	preempt_disable();
+	rcu_read_lock();
 
 	/* Ensure the address is in a text area, and find a module if exists. */
 	*probed_mod = NULL;
@@ -1612,7 +1612,7 @@  static int check_kprobe_address_safe(struct kprobe *p,
 	}
 
 out:
-	preempt_enable();
+	rcu_read_unlock();
 	jump_label_unlock();
 
 	return ret;