From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Gustavo A. R. Silva" Subject: Re: [PATCH][next] cgroup: Avoid -Wstringop-overflow warnings Date: Tue, 15 Aug 2023 13:04:32 -0600 Message-ID: References: Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=embeddedor.com; s=default; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=oDTpbnZtb5YY58cxQ1+wqrLvX74qH9kX1x/86gt1r6c=; b=GYqk+IEZHDNl4F1KNkrjKQ4GCv A8WuEZWAoPnmMiy5LJ5rLCvLrfBUjja3movkQMpr/X3RBuLXmLXSa2djw6dKXzKucDKJi/n0OzHsC lgCkFhGiIVfQpofwfVRHtXlcHDGmrQXJIlLN2PSiVfQxmdIM0765db6fe82HYihlPM2Wgwn0/D8eP i5nCbb2biNKRb53PVBwCZRjEqtmn5+EFTXARPbPFiG9+6QkFJxpCavWSSp4tRVGiuoVBC2TDajzeg upx233SUSeGEbPUt3NXjHVv7jeWCyXSBmlaN+7ngIYg5E/XAJLYVujq0sfutwtvAhpl2ITu/tH/74 MUNz Content-Language: en-US In-Reply-To: List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: "Gustavo A. R. Silva" , Tejun Heo , Zefan Li , Johannes Weiner Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Hi all, I wonder if you have any suggestions on how to address this issue. As it seems that my last attempt caused some boot failures[1][2]. At first, I thought that the right way to fix this was through a similar fix as this one[3]. But it seems I'm missing something else that I cannot determine yet. These -Wstringop-overflow warnings are mostly the last ones remaining before we can finally enable this compiler option, globally. Any help or advice on how to properly address this is greatly appreciated. :) Thanks! -- Gustavo [1] https://lore.kernel.org/linux-hardening/726aae97-755d-9806-11d4-2fb21aa93428@arm.com/ [2] https://lore.kernel.org/linux-hardening/361c2f87-1424-f452-912f-0e4a339f5c46@kernel.org/ [3] https://git.kernel.org/linus/d20d30ebb199 On 6/14/23 19:18, 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));