linux-kernel - Re: [PATCH V2 2/7] mm/gup: add gup trace points

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20151203140614.75f49aad@gandalf.local.home>
Date:	Thu, 3 Dec 2015 14:06:14 -0500
From:	Steven Rostedt <rostedt@...dmis.org>
To:	"Shi, Yang" <yang.shi@...aro.org>
Cc:	Dave Hansen <dave.hansen@...el.com>, akpm@...ux-foundation.org,
	mingo@...hat.com, linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	linaro-kernel@...ts.linaro.org
Subject: Re: [PATCH V2 2/7] mm/gup: add gup trace points

On Thu, 03 Dec 2015 10:36:18 -0800
"Shi, Yang" <yang.shi@...aro.org> wrote:

> > called directly that calls these functions internally and the tracepoint
> > can trap the return value.  
> 
> This will incur more changes in other subsystems (futex, kvm, etc), I'm 
> not sure if it is worth making such changes to get return value.

No, it wouldn't require any changes outside of this.

-long __get_user_pages(..)
+static long __get_user_pages_internal(..)
{
  [..]
}
+
+long __get_user_pages(..)
+{
+	long ret;
+	ret = __get_user_pages_internal(..);
+	trace_get_user_pages(.., ret)
+}

> 
> > I can probably make function_graph tracer give return values, although
> > it will give a return value for void functions as well. And it may give
> > long long returns for int returns that may have bogus data in the
> > higher bits.  
> 
> If the return value requirement is not limited to gup, the approach 
> sounds more reasonable.
>

Others have asked about it. Maybe I should do it.

-- Steve

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/