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Tsirkin" , Jason Wang , Xuan Zhuo , Eugenio =?iso-8859-1?Q?P=E9rez?= , Vivek Goyal , Dave Young , Thomas Huth , Cornelia Huck , Janosch Frank , Claudio Imbrenda , Eric Farman , Andrew Morton Subject: Re: [PATCH v1 03/11] fs/proc/vmcore: disallow vmcore modifications after the vmcore was opened Message-ID: References: <20241025151134.1275575-1-david@redhat.com> <20241025151134.1275575-4-david@redhat.com> Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241025151134.1275575-4-david@redhat.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 On 10/25/24 at 05:11pm, David Hildenbrand wrote: ......snip... > @@ -1482,6 +1470,10 @@ int vmcore_add_device_dump(struct vmcoredd_data *data) > return -EINVAL; > } > > + /* We'll recheck under lock later. */ > + if (data_race(vmcore_opened)) > + return -EBUSY; As I commented to patch 7, if vmcore is opened and closed after checking, do we need to give up any chance to add device dumping as below? fd = open(/proc/vmcore); ...do checking; close(fd); quit any device dump adding; run makedumpfile on s390; ->fd = open(/proc/vmcore); -> try to dump; ->close(fd); > + > if (!data || !strlen(data->dump_name) || > !data->vmcoredd_callback || !data->size) > return -EINVAL; > @@ -1515,12 +1507,16 @@ int vmcore_add_device_dump(struct vmcoredd_data *data) > dump->buf = buf; > dump->size = data_size; > > - /* Add the dump to driver sysfs list */ > + /* Add the dump to driver sysfs list and update the elfcore hdr */ > mutex_lock(&vmcore_mutex); > - list_add_tail(&dump->list, &vmcoredd_list); > - mutex_unlock(&vmcore_mutex); > + if (vmcore_opened) { > + ret = -EBUSY; > + goto out_err; > + } > > + list_add_tail(&dump->list, &vmcoredd_list); > vmcoredd_update_size(data_size); > + mutex_unlock(&vmcore_mutex); > return 0; > > out_err: > -- > 2.46.1 >