From: Siddh Raman Pant via Linux-kernel-mentees <linux-kernel-mentees@lists.linuxfoundation.org> To: "Ingo Molnar" <mingo@kernel.org> Cc: Dave Hansen <dave.hansen@linux.intel.com>, Peter Zijlstra <peterz@infradead.org>, x86 <x86@kernel.org>, linux-kernel <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>, Thomas Gleixner <tglx@linutronix.de>, linux-kernel-mentees <linux-kernel-mentees@lists.linuxfoundation.org> Subject: Re: [PATCH] x86/numa: Use cpumask_available instead of hardcoded NULL check Date: Tue, 02 Aug 2022 21:59:05 +0530 [thread overview] Message-ID: <1825f63b142.8968bde3116633.1242410031840350968@siddh.me> (raw) In-Reply-To: <YukFgFTaq4Aw+uht@gmail.com> On Tue, 02 Aug 2022 16:37:44 +0530 Ingo Molnar <mingo@kernel.org> wrote: > Your fix makes sense I suppose, but I'm wondering how testing didn't > trigger this warning. > > Off-stack isn't a rare config option: > > kepler:~/tip> make allmodconfig > # > # No change to .config > # > kepler:~/tip> grep CPUMASK_OFFSTACK .config > CONFIG_CPUMASK_OFFSTACK=y > kepler:~/tip> > > What am I missing? Maybe this triggers on certain config options set, or maybe due to new gcc version? (I'm using gcc-12, I also likely saw while on gcc-11.) It nevertheless is a helpful warning. I just now tried `make defconfig` (default configuration based on 'x86_64_defconfig') and compiling with `make -j13 all`, and gcc doesn't give any warning. (CONFIG_CPUMASK_OFFSTACK isn't even listed in the .config file produced, grep fails.) The config on which I can reproduce the warning can be found here: https://gist.github.com/siddhpant/0197ea2b9873e8719d5d7ef991e2cd89 (It has 8969 lines, thus uploaded as a gist.) This is a modification of a config found on syzkaller, which I was using to compile and test some bug. I had noticed the gcc warning earlier while on similar detours and usually ignored it, but now I finally took a look. I tested compiling with it 5 times (`make clean` and `make -j13 all`), and gcc gave the warning in all attempts. I also tried `make -j1 all`, which also had gcc spitting out the warning, so it cannot be any race. > > Fixes: c032ef60d1aa ("cpumask: convert node_to_cpumask_map[] to cpumask_var_t") > > Fixes: de2d9445f162 ("x86: Unify node_to_cpumask_map handling between 32 and 64bit") > > These are ancient commits from 2009 & 2011. Yes, that's where blaming the file leads me to. Thanks, Siddh _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
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From: Siddh Raman Pant <code@siddh.me> To: "Ingo Molnar" <mingo@kernel.org> Cc: "x86" <x86@kernel.org>, "Dave Hansen" <dave.hansen@linux.intel.com>, "Andy Lutomirski" <luto@kernel.org>, "Peter Zijlstra" <peterz@infradead.org>, "Thomas Gleixner" <tglx@linutronix.de>, "Ingo Molnar" <mingo@redhat.com>, "Borislav Petkov" <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>, "linux-kernel" <linux-kernel@vger.kernel.org>, "linux-kernel-mentees" <linux-kernel-mentees@lists.linuxfoundation.org> Subject: Re: [PATCH] x86/numa: Use cpumask_available instead of hardcoded NULL check Date: Tue, 02 Aug 2022 21:59:05 +0530 [thread overview] Message-ID: <1825f63b142.8968bde3116633.1242410031840350968@siddh.me> (raw) In-Reply-To: <YukFgFTaq4Aw+uht@gmail.com> On Tue, 02 Aug 2022 16:37:44 +0530 Ingo Molnar <mingo@kernel.org> wrote: > Your fix makes sense I suppose, but I'm wondering how testing didn't > trigger this warning. > > Off-stack isn't a rare config option: > > kepler:~/tip> make allmodconfig > # > # No change to .config > # > kepler:~/tip> grep CPUMASK_OFFSTACK .config > CONFIG_CPUMASK_OFFSTACK=y > kepler:~/tip> > > What am I missing? Maybe this triggers on certain config options set, or maybe due to new gcc version? (I'm using gcc-12, I also likely saw while on gcc-11.) It nevertheless is a helpful warning. I just now tried `make defconfig` (default configuration based on 'x86_64_defconfig') and compiling with `make -j13 all`, and gcc doesn't give any warning. (CONFIG_CPUMASK_OFFSTACK isn't even listed in the .config file produced, grep fails.) The config on which I can reproduce the warning can be found here: https://gist.github.com/siddhpant/0197ea2b9873e8719d5d7ef991e2cd89 (It has 8969 lines, thus uploaded as a gist.) This is a modification of a config found on syzkaller, which I was using to compile and test some bug. I had noticed the gcc warning earlier while on similar detours and usually ignored it, but now I finally took a look. I tested compiling with it 5 times (`make clean` and `make -j13 all`), and gcc gave the warning in all attempts. I also tried `make -j1 all`, which also had gcc spitting out the warning, so it cannot be any race. > > Fixes: c032ef60d1aa ("cpumask: convert node_to_cpumask_map[] to cpumask_var_t") > > Fixes: de2d9445f162 ("x86: Unify node_to_cpumask_map handling between 32 and 64bit") > > These are ancient commits from 2009 & 2011. Yes, that's where blaming the file leads me to. Thanks, Siddh
next prev parent reply other threads:[~2022-08-02 16:29 UTC|newest] Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-07-31 16:09 [PATCH] x86/numa: Use cpumask_available instead of hardcoded NULL check Siddh Raman Pant via Linux-kernel-mentees 2022-07-31 16:09 ` Siddh Raman Pant 2022-08-02 11:07 ` Ingo Molnar 2022-08-02 11:07 ` Ingo Molnar 2022-08-02 16:29 ` Siddh Raman Pant via Linux-kernel-mentees [this message] 2022-08-02 16:29 ` Siddh Raman Pant 2022-08-03 8:48 ` Ingo Molnar 2022-08-03 8:48 ` Ingo Molnar 2022-08-03 8:58 ` Siddh Raman Pant via Linux-kernel-mentees 2022-08-03 8:58 ` Siddh Raman Pant 2022-08-03 9:08 ` Ingo Molnar 2022-08-03 9:08 ` Ingo Molnar 2022-08-03 9:21 ` Siddh Raman Pant 2022-08-03 9:21 ` Siddh Raman Pant via Linux-kernel-mentees 2022-08-03 9:42 ` Ingo Molnar 2022-08-03 9:42 ` Ingo Molnar 2022-08-03 9:46 ` Siddh Raman Pant via Linux-kernel-mentees 2022-08-03 9:46 ` Siddh Raman Pant 2022-08-03 15:41 ` [tip: x86/urgent] " tip-bot2 for Siddh Raman Pant
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