linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Peter Zijlstra <peterz@infradead.org>
To: "Pratik R. Sampat" <psampat@linux.ibm.com>
Cc: bristot@redhat.com, christian@brauner.io, ebiederm@xmission.com,
	lizefan.x@bytedance.com, tj@kernel.org, hannes@cmpxchg.org,
	mingo@kernel.org, juri.lelli@redhat.com,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	cgroups@vger.kernel.org, containers@lists.linux.dev,
	containers@lists.linux-foundation.org, pratik.r.sampat@gmail.com
Subject: Re: [RFC 1/5] ns: Introduce CPU Namespace
Date: Sun, 10 Oct 2021 00:37:39 +0200	[thread overview]
Message-ID: <20211009223739.GY174703@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20211009151243.8825-2-psampat@linux.ibm.com>

On Sat, Oct 09, 2021 at 08:42:39PM +0530, Pratik R. Sampat wrote:
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 2d9ff40f4661..0413175e6d73 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -27,6 +27,8 @@
>  #include "pelt.h"
>  #include "smp.h"
>  
> +#include <linux/cpu_namespace.h>
> +
>  /*
>   * Export tracepoints that act as a bare tracehook (ie: have no trace event
>   * associated with them) to allow external modules to probe them.
> @@ -7559,6 +7561,7 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
>  {
>  	cpumask_var_t cpus_allowed, new_mask;
>  	struct task_struct *p;
> +	cpumask_t temp;
>  	int retval;
>  
>  	rcu_read_lock();

You're not supposed to put a cpumask_t on stack. Those things can be
huge.

> @@ -7682,8 +7686,9 @@ SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
>  long sched_getaffinity(pid_t pid, struct cpumask *mask)
>  {
>  	struct task_struct *p;
> +	cpumask_var_t temp;
>  	unsigned long flags;
> -	int retval;
> +	int retval, cpu;
>  
>  	rcu_read_lock();
>  
> @@ -7698,6 +7703,13 @@ long sched_getaffinity(pid_t pid, struct cpumask *mask)
>  
>  	raw_spin_lock_irqsave(&p->pi_lock, flags);
>  	cpumask_and(mask, &p->cpus_mask, cpu_active_mask);
> +	cpumask_clear(temp);

There's a distinct lack of allocating temp before use. Are you sure you
actually tested this?


  reply	other threads:[~2021-10-09 22:41 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-09 15:12 [RFC 0/5] kernel: Introduce CPU Namespace Pratik R. Sampat
2021-10-09 15:12 ` [RFC 1/5] ns: " Pratik R. Sampat
2021-10-09 22:37   ` Peter Zijlstra [this message]
2021-10-09 15:12 ` [RFC 2/5] ns: Add scrambling functionality to CPU namespace Pratik R. Sampat
2021-10-09 15:12 ` [RFC 3/5] cpuset/cpuns: Make cgroup CPUset CPU namespace aware Pratik R. Sampat
2021-10-09 15:12 ` [RFC 4/5] cpu/cpuns: Make sysfs " Pratik R. Sampat
2021-10-09 15:12 ` [RFC 5/5] proc/cpuns: Make procfs load stats " Pratik R. Sampat
2021-10-09 22:41 ` [RFC 0/5] kernel: Introduce CPU Namespace Peter Zijlstra
2021-10-11 10:11 ` Christian Brauner
2021-10-11 14:17   ` Michal Koutný
2021-10-11 17:42     ` Tejun Heo
2021-10-12  8:42   ` Pratik Sampat
2021-10-14 22:14     ` Tejun Heo
2021-10-18 15:29       ` Pratik Sampat
2021-10-18 16:29         ` Tejun Heo
2021-10-20 10:44           ` Pratik Sampat
2021-10-20 16:35             ` Tejun Heo
2021-10-21  7:44               ` Pratik Sampat
2021-10-21 17:06                 ` Tejun Heo
2021-10-21 17:15             ` Eric W. Biederman

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20211009223739.GY174703@worktop.programming.kicks-ass.net \
    --to=peterz@infradead.org \
    --cc=bristot@redhat.com \
    --cc=cgroups@vger.kernel.org \
    --cc=christian@brauner.io \
    --cc=containers@lists.linux-foundation.org \
    --cc=containers@lists.linux.dev \
    --cc=ebiederm@xmission.com \
    --cc=hannes@cmpxchg.org \
    --cc=juri.lelli@redhat.com \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=lizefan.x@bytedance.com \
    --cc=mingo@kernel.org \
    --cc=pratik.r.sampat@gmail.com \
    --cc=psampat@linux.ibm.com \
    --cc=tj@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).