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R. Silva" , Tejun Heo , Zefan Li , Johannes Weiner Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, Kees Cook References: <726aae97-755d-9806-11d4-2fb21aa93428@arm.com> From: "Gustavo A. R. Silva" In-Reply-To: <726aae97-755d-9806-11d4-2fb21aa93428@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 187.162.21.192 X-Source-L: No X-Exim-ID: 1qCKyr-000Aa9-Dy X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: 187-162-21-192.static.axtel.net ([192.168.15.8]) [187.162.21.192]:43202 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 3 X-Org: HG=hgshared;ORG=hostgator; X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes X-CMAE-Envelope: MS4xfIcQkW0jDi8w2+NbJ+Trh4cndyQ5RMF8ipreME1Q353xRFrGYN2Hs2utbqNb6AhO+pOrrS8GhP1/QOcNS/1D5Eq+nBjbDOE3J4R5/RDmylz7RF/HmJyl XsJxTLft4sOiVzLae0onBpNK/5OxbXEa5963N54MEI9w8QX6dtHTdZ66vSQoRhzyzPyG3XZ86J4jvwIhow3SKeZbQS1OxynHvi4Bj3rxTujAKf/jM8MT6HA8 X-Spam-Status: No, score=-2.9 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,NICE_REPLY_A,RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H4,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_PASS, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi! On 6/22/23 04:11, Steven Price wrote: > On 15/06/2023 02:18, Gustavo A. R. Silva wrote: >> Address the following -Wstringop-overflow warnings seen when >> built with ARM architecture and aspeed_g4_defconfig configuration >> (notice that under this configuration CGROUP_SUBSYS_COUNT == 0): >> kernel/cgroup/cgroup.c:1208:16: warning: 'find_existing_css_set' accessing 4 bytes in a region of size 0 [-Wstringop-overflow=] >> kernel/cgroup/cgroup.c:1258:15: warning: 'css_set_hash' accessing 4 bytes in a region of size 0 [-Wstringop-overflow=] >> kernel/cgroup/cgroup.c:6089:18: warning: 'css_set_hash' accessing 4 bytes in a region of size 0 [-Wstringop-overflow=] >> kernel/cgroup/cgroup.c:6153:18: warning: 'css_set_hash' accessing 4 bytes in a region of size 0 [-Wstringop-overflow=] >> >> These changes are based on commit d20d30ebb199 ("cgroup: Avoid compiler >> warnings with no subsystems"). >> >> Signed-off-by: Gustavo A. R. Silva >> --- >> kernel/cgroup/cgroup.c | 6 ++++++ >> 1 file changed, 6 insertions(+) >> >> diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c >> index cd497b90e11a..1ee76e62eb98 100644 >> --- a/kernel/cgroup/cgroup.c >> +++ b/kernel/cgroup/cgroup.c >> @@ -1200,6 +1200,9 @@ static struct css_set *find_css_set(struct css_set *old_cset, >> unsigned long key; >> int ssid; >> >> + if (!CGROUP_HAS_SUBSYS_CONFIG) >> + return NULL; >> + >> lockdep_assert_held(&cgroup_mutex); >> >> /* First see if we already have a cgroup group that matches >> @@ -6045,6 +6048,9 @@ int __init cgroup_init(void) >> struct cgroup_subsys *ss; >> int ssid; >> >> + if (!CGROUP_HAS_SUBSYS_CONFIG) >> + return -EINVAL; >> + >> BUILD_BUG_ON(CGROUP_SUBSYS_COUNT > 16); >> BUG_ON(cgroup_init_cftypes(NULL, cgroup_base_files)); >> BUG_ON(cgroup_init_cftypes(NULL, cgroup_psi_files)); > > This change (which landed in linux-next) causes a boot failure on my > (arm32) board because the cgroup filesystem isn't created which upsets > systemd: > > [ 11.474767] systemd[1]: Failed to mount tmpfs at /sys/fs/cgroup: No such file or directory > [ 11.489933] systemd[1]: Failed to mount cgroup at /sys/fs/cgroup/systemd: No such file or directory > [!!!!!!] Failed to mount API filesystems. > > Reverting this commit on the head of linux-next gets the board working > again. Thanks for reporting this issue. I'll take a look. -- Gustavo