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Thu, 03 Nov 2022 11:18:21 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id A140930012F; Thu, 3 Nov 2022 12:18:14 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 89B1320424903; Thu, 3 Nov 2022 12:18:14 +0100 (CET) Date: Thu, 3 Nov 2022 12:18:14 +0100 From: Peter Zijlstra To: Alexander Potapenko Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Borislav Petkov , Dave Hansen , Ingo Molnar , Thomas Gleixner , x86@kernel.org Subject: Re: [PATCH 5/5] x86/traps: avoid KMSAN bugs originating from handle_bug() Message-ID: References: <20221102110611.1085175-1-glider@google.com> <20221102110611.1085175-5-glider@google.com> MIME-Version: 1.0 Content-Type: text/plain; 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t=1667474305; a=rsa-sha256; cv=none; b=ocDJDMBDNR39gfoLzgBtjVkTQvfaq8J7SP6ca499escKtIzA6ONflUHheswieWtdwtVpwM FiwSFZrHiZCT8m8pBSH2ADlEmJ7sZJrkEd7rypZxUo+30k8vnYdJxM4MM3VxrDK/gxaInD UprcNY4wn6R1/O2RRq/ytIN1iwS1SnU= X-Stat-Signature: r3hxm63s9h5s33zq1fe47aq8a5s3r8nh X-Rspamd-Queue-Id: E6BA7180008 X-Rspamd-Server: rspam06 X-Rspam-User: Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=EPeqifQD; spf=none (imf24.hostedemail.com: domain of peterz@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=peterz@infradead.org; dmarc=none X-HE-Tag: 1667474303-399989 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: On Wed, Nov 02, 2022 at 12:06:11PM +0100, Alexander Potapenko wrote: > diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c > index 178015a820f08..d3fdec706f1d2 100644 > --- a/arch/x86/kernel/traps.c > +++ b/arch/x86/kernel/traps.c > @@ -15,6 +15,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -301,6 +302,12 @@ static noinstr bool handle_bug(struct pt_regs *regs) > { > bool handled = false; > > + /* > + * Normally @regs are unpoisoned by irqentry_enter(), but handle_bug() > + * is a rare case that uses @regs without passing them to > + * irqentry_enter(). > + */ > + kmsan_unpoison_entry_regs(regs); > if (!is_valid_bugaddr(regs->ip)) > return handled; > Should we place this kmsan_unpoison_entry_regs() after the instrumentation_begin() ?