linux-kernel - Re: [PATCH] mm: memcg: fix unit conversion for K() macro in OOM log

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: <a3676b26-feca-474a-b09e-33986f53c998@suse.cz>
Date: Wed, 17 Dec 2025 10:08:42 +0100
From: Vlastimil Babka <vbabka@...e.cz>
To: Shakeel Butt <shakeel.butt@...ux.dev>,
 Andrew Morton <akpm@...ux-foundation.org>
Cc: Johannes Weiner <hannes@...xchg.org>, Michal Hocko <mhocko@...nel.org>,
 Roman Gushchin <roman.gushchin@...ux.dev>,
 Muchun Song <muchun.song@...ux.dev>, Meta kernel team
 <kernel-team@...a.com>, cgroups@...r.kernel.org, linux-mm@...ck.org,
 linux-kernel@...r.kernel.org, Chris Mason <clm@...com>
Subject: Re: [PATCH] mm: memcg: fix unit conversion for K() macro in OOM log

On 12/16/25 22:20, Shakeel Butt wrote:
> The commit bc8e51c05ad5 ("mm: memcg: dump memcg protection info on oom
> or alloc failures") added functionality to dump memcg protections on OOM
> or allocation failures. It uses K() macro to dump the information and
> passes bytes to the macro. However the macro take number of pages
> instead of bytes. It is defined as:
> 
>  #define K(x) ((x) << (PAGE_SHIFT-10))
> 
> Let's fix this.
> 
> Signed-off-by: Shakeel Butt <shakeel.butt@...ux.dev>
> Reported-by: Chris Mason <clm@...com>
> Fixes: bc8e51c05ad5 ("mm: memcg: dump memcg protection info on oom or alloc failures")

Acked-by: Vlastimil Babka <vbabka@...e.cz>

> ---
>  mm/memcontrol.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index e2e49f4ec9e0..6f000f0e76d2 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -5638,6 +5638,6 @@ void mem_cgroup_show_protected_memory(struct mem_cgroup *memcg)
>  		memcg = root_mem_cgroup;
>  
>  	pr_warn("Memory cgroup min protection %lukB -- low protection %lukB",
> -		K(atomic_long_read(&memcg->memory.children_min_usage)*PAGE_SIZE),
> -		K(atomic_long_read(&memcg->memory.children_low_usage)*PAGE_SIZE));
> +		K(atomic_long_read(&memcg->memory.children_min_usage)),
> +		K(atomic_long_read(&memcg->memory.children_low_usage)));
>  }