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[109.81.83.231]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-36b8f51eaf5sm584855f8f.29.2024.07.30.00.13.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Jul 2024 00:13:39 -0700 (PDT) Date: Tue, 30 Jul 2024 09:13:38 +0200 From: Michal Hocko To: viro@kernel.org Cc: linux-fsdevel@vger.kernel.org, amir73il@gmail.com, bpf@vger.kernel.org, brauner@kernel.org, cgroups@vger.kernel.org, kvm@vger.kernel.org, netdev@vger.kernel.org, torvalds@linux-foundation.org Subject: Re: [PATCH 01/39] memcg_write_event_control(): fix a user-triggerable oops Message-ID: References: <20240730050927.GC5334@ZenIV> <20240730051625.14349-1-viro@kernel.org> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240730051625.14349-1-viro@kernel.org> On Tue 30-07-24 01:15:47, viro@kernel.org wrote: > From: Al Viro > > we are *not* guaranteed that anything past the terminating NUL > is mapped (let alone initialized with anything sane). > > [the sucker got moved in mainline] > You could have preserved Fixes: 0dea116876ee ("cgroup: implement eventfd-based generic API for notifications") Cc: stable > Signed-off-by: Al Viro and Acked-by: Michal Hocko > --- > mm/memcontrol-v1.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c > index 2aeea4d8bf8e..417c96f2da28 100644 > --- a/mm/memcontrol-v1.c > +++ b/mm/memcontrol-v1.c > @@ -1842,9 +1842,12 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file *of, > buf = endp + 1; > > cfd = simple_strtoul(buf, &endp, 10); > - if ((*endp != ' ') && (*endp != '\0')) > + if (*endp == '\0') > + buf = endp; > + else if (*endp == ' ') > + buf = endp + 1; > + else > return -EINVAL; > - buf = endp + 1; > > event = kzalloc(sizeof(*event), GFP_KERNEL); > if (!event) > -- > 2.39.2 > -- Michal Hocko SUSE Labs