linux-kernel - Re: [PATCH] get_signal: simplify/cleanup the the usage of ksig->info

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Message-ID: <20240223144458.GD8267@redhat.com>
Date: Fri, 23 Feb 2024 15:44:59 +0100
From: Oleg Nesterov <oleg@...hat.com>
To: Wen Yang <wenyang.linux@...mail.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Christian Brauner <brauner@...nel.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] get_signal: simplify/cleanup the the usage of ksig->info

On 02/23, Oleg Nesterov wrote:
>
> On 02/23, Oleg Nesterov wrote:
> >
> > On 02/23, Wen Yang wrote:
> > >
> > >
> > > On 2024/2/23 18:50, Oleg Nesterov wrote:
> > > >+			/*
> > > >+			 * implies do_group_exit(), no need to initialize
> > > >+			 * ksig->info
> > > >+			 */
> > > >  			goto fatal;
> > >
> > > There is little question:
> > > If the this conditions is met:
> > >    current->flags & PF_USER_WORKER
> > > It may execute “goto out“ instead of do_group_exit().
> >
> > Yes, but vhost/io workers do not use ksig at all.
>
> Ah, wait...
>
> I forgot about the ->sa_flags check before hide_si_addr_tag_bits().
>
> OK, thanks... I'll send V2.

Tomorrow.

I'll recheck, but I think we need the patch below as 1/2 regadless of
this change

Oleg.
---

--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2897,13 +2897,13 @@ bool get_signal(struct ksignal *ksig)
 		/* NOTREACHED */
 	}
 	spin_unlock_irq(&sighand->siglock);
-out:
+
 	ksig->sig = signr;
 
 	if (!(ksig->ka.sa.sa_flags & SA_EXPOSE_TAGBITS))
 		hide_si_addr_tag_bits(ksig);
-
-	return ksig->sig > 0;
+out:
+	return signr > 0;
 }
 
 /**