From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D5BB1CE9D45 for ; Tue, 6 Jan 2026 15:21:03 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4B02E6B0088; Tue, 6 Jan 2026 10:21:03 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 467576B008A; Tue, 6 Jan 2026 10:21:03 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3943F6B0093; Tue, 6 Jan 2026 10:21:03 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 2629D6B0088 for ; Tue, 6 Jan 2026 10:21:03 -0500 (EST) Received: from smtpin22.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id D9A991AA01C for ; 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b=1zbT3i0wARlJBo7Qhxz0APyvULEO8DSjrHH8L3dkijYVm9INZdXthIogoCAoFJP0yPX6mj IuFFoNGzW1hpdwyeXO0CUOuvpqXR3aSmhmn5GHSe/76ApOKbAiWibOjZb1vYrilBYUvd2m mBRhVP+emvdU1+Rd6pbsP1dWfI5qN9E= Received: from omf13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 384438ABED; Tue, 6 Jan 2026 15:20:59 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf13.hostedemail.com (Postfix) with ESMTPA id ECE9C2000D; Tue, 6 Jan 2026 15:20:55 +0000 (UTC) Date: Tue, 6 Jan 2026 10:21:20 -0500 From: Steven Rostedt To: Vlastimil Babka Cc: Andrew Morton , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , Sebastian Andrzej Siewior , Clark Williams , Mel Gorman , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, stable@vger.kernel.org, kernel test robot , Matthew Wilcox Subject: Re: [PATCH mm-hotfixes] mm/page_alloc: prevent pcp corruption with SMP=n Message-ID: <20260106102120.4272260e@gandalf.local.home> In-Reply-To: <04624b16-40ea-42c6-b687-4013796e4779@suse.cz> References: <20260105-fix-pcp-up-v1-1-5579662d2071@suse.cz> <20260105164036.32a22c2e@gandalf.local.home> <04624b16-40ea-42c6-b687-4013796e4779@suse.cz> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX19Cnps0ORM9wOahzNOtx0DT319eAQmpInc= X-HE-Meta: U2FsdGVkX18qn3xbopg0HXbkKioqQiII+KS+SESHqD4DmcTs87FqtTwlrJHklBpNtixlk38wVYTWl58BF19c+TgMm92szMg+VQcnCFJNRD4AHB5RYUf1fMNVhQROcMki6PZDC0Yr/gdYibD8NrC5wWG37/dIiBSLdagQmEYQCqe4JL5jxVSUPjcFfM05fbU3ts99MchYGe3AcRK+OZCbq7ODj7gIEfL2XaQLW0BDxwqvZlqdVSGAODffh/iEG18lJF8gLB7q7qfRDRhLXeXY2dl8zEBMD79afbk00Tj1xF5+SjEf+Sp0KISnnd++GCQG X-HE-Tag-Orig: 1767712855-198917 X-Rspamd-Queue-Id: 1B552160004 X-Rspamd-Server: rspam03 X-Stat-Signature: 7ue5a44wypk99ky14qm411h7f5gs61tt X-Rspam-User: X-HE-Tag: 1767712860-490797 X-HE-Meta: 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 3xcO+jmS PMxcb X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, 6 Jan 2026 09:28:29 +0100 Vlastimil Babka wrote: > >> + */ > >> +#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT) > >> +static inline void __flags_noop(unsigned long *flags) { } > >> +#define spin_lock_maybe_irqsave(lock, flags) \ > >> +({ \ > >> + __flags_noop(&(flags)); \ > >> + spin_lock(lock); \ > >> +}) > >> +#define spin_unlock_maybe_irqrestore(lock, flags) \ > >> +({ \ > >> + spin_unlock(lock); \ > >> + __flags_noop(&(flags)); \ > >> +}) > >> +#else > >> +#define spin_lock_maybe_irqsave(lock, flags) spin_lock_irqsave(lock, flags) > >> +#define spin_unlock_maybe_irqrestore(lock, flags) spin_unlock_irqrestore(lock, flags) > >> +#endif > >> + > > > > These are very generic looking names for something specific for > > page_alloc.c. Could you add a prefix of some kind to make it easy to see > > that these are specific to the mm code? > > > > mm_spin_lock_maybe_irqsave() ? > OK, I think it's best like this: Yeah, thanks. -- Steve > > ----8<---- > >From a6da5d9e3db005a2f44f3196814d7253dce21d3e Mon Sep 17 00:00:00 2001 > From: Vlastimil Babka > Date: Tue, 6 Jan 2026 09:23:37 +0100 > Subject: [PATCH] mm/page_alloc: prevent pcp corruption with SMP=n - fix > > Add pcp_ prefix to the spin_lock_irqsave wrappers, per Steven. > With that make them also take pcp pointer and reference the lock > field themselves, to be like the existing pcp trylock wrappers. > > Signed-off-by: Vlastimil Babka > --- > mm/page_alloc.c | 30 ++++++++++++++++-------------- > 1 file changed, 16 insertions(+), 14 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index ec3551d56cde..dd72ff39da8c 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -177,19 +177,21 @@ static inline void __pcp_trylock_noop(unsigned long *flags) { } > */ > #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT) > static inline void __flags_noop(unsigned long *flags) { } > -#define spin_lock_maybe_irqsave(lock, flags) \ > +#define pcp_spin_lock_maybe_irqsave(ptr, flags) \ > ({ \ > __flags_noop(&(flags)); \ > - spin_lock(lock); \ > + spin_lock(&(ptr)->lock); \ > })