linux-kernel - Re: [PATCH] rcu: Handle failure of memory allocation functions

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <20220611163432.GM1790663@paulmck-ThinkPad-P17-Gen-1>
Date:   Sat, 11 Jun 2022 09:34:32 -0700
From:   "Paul E. McKenney" <paulmck@...nel.org>
To:     Li Qiong <liqiong@...china.com>
Cc:     Davidlohr Bueso <dave@...olabs.net>,
        Josh Triplett <josh@...htriplett.org>,
        Frederic Weisbecker <frederic@...nel.org>,
        Neeraj Upadhyay <quic_neeraju@...cinc.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        Lai Jiangshan <jiangshanlai@...il.com>,
        Joel Fernandes <joel@...lfernandes.org>,
        linux-kernel@...r.kernel.org, rcu@...r.kernel.org,
        hukun@...china.com, qixu@...china.com, yuzhe@...china.com,
        renyu@...china.com
Subject: Re: [PATCH] rcu: Handle failure of memory allocation functions

On Sat, Jun 11, 2022 at 05:30:55PM +0800, Li Qiong wrote:
> Add warning when these functions (eg:kmalloc,vmalloc) fail, handle the
> failure.
> 
> Signed-off-by: Li Qiong <liqiong@...china.com>

Good catch, thank you!  However...

> ---
>  kernel/rcu/rcutorture.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
> index 7120165a9342..97f90e304ae3 100644
> --- a/kernel/rcu/rcutorture.c
> +++ b/kernel/rcu/rcutorture.c
> @@ -1991,6 +1991,10 @@ static void rcu_torture_mem_dump_obj(void)
>  
>  	kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL);

As long as we are checking, why not also check this one?

							Thanx, Paul

>  	rhp = kmem_cache_alloc(kcp, GFP_KERNEL);
> +	if (WARN_ON_ONCE(!rhp)) {
> +		kmem_cache_destroy(kcp);
> +		return;
> +	}
>  	pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z);
>  	pr_alert("mem_dump_obj(ZERO_SIZE_PTR):");
>  	mem_dump_obj(ZERO_SIZE_PTR);
> @@ -2007,6 +2011,8 @@ static void rcu_torture_mem_dump_obj(void)
>  	kmem_cache_free(kcp, rhp);
>  	kmem_cache_destroy(kcp);
>  	rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
> +	if (WARN_ON_ONCE(!rhp))
> +		return;
>  	pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
>  	pr_alert("mem_dump_obj(kmalloc %px):", rhp);
>  	mem_dump_obj(rhp);
> @@ -2014,6 +2020,8 @@ static void rcu_torture_mem_dump_obj(void)
>  	mem_dump_obj(&rhp->func);
>  	kfree(rhp);
>  	rhp = vmalloc(4096);
> +	if (WARN_ON_ONCE(!rhp))
> +		return;
>  	pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
>  	pr_alert("mem_dump_obj(vmalloc %px):", rhp);
>  	mem_dump_obj(rhp);
> -- 
> 2.11.0
>