From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id AD47F246768; Mon, 27 Apr 2026 03:39:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777261160; cv=none; b=heAU3kHp6dKFdWYb31cbjaGesjBDEi4oXpH0Y4fUUUoCDx57PLCahMyKJzpqF/8UUCwxX5EhfvCRmuLY/nqG5+3/MmUIjScJB/uPO79ssBEKDi/Mh156R7zdUoIYuwzmAKZS/FoQ+vjNVTlw9RuNJiZiocLXR2e/WpUqLUzMaB4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777261160; c=relaxed/simple; bh=LCn0RaEC1G+RSX7YHBiuKpju1CY4aw/B8Hwl6UvdVVs=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Hw8KCTANbncFNyghUKBGfgEji1mZrOJeyCnsnNrclnKvamkfz9x/ePUJrjKfAW9vY5nDvTSJwCpzjWrfE9luMrdoeO1AQjsib+Px/6NFkXwIeRcf/TWD71sIyZSFrwIwUY4KuoDlGhQtgQTaYMHZC+H5mbv5to+hI7KR6hyA8T0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=a7iLWY4Q; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="a7iLWY4Q" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 18B641684; Sun, 26 Apr 2026 20:39:12 -0700 (PDT) Received: from [10.164.148.37] (MacBook-Pro.blr.arm.com [10.164.148.37]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 956BF3F763; Sun, 26 Apr 2026 20:39:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1777261157; bh=LCn0RaEC1G+RSX7YHBiuKpju1CY4aw/B8Hwl6UvdVVs=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=a7iLWY4QB8QkFuzmIeDOuDWqi+s4PDrdRofCrcgpwk7g0s79ucMCB53kHVem1hj2T pSQCImk33dpBgQBRs2a5GPjNO98tgnqSqiwrUjeWuJ5Tt9BG/N4hCvQsUw154sQYGh pPozkR//I3ob+wI5OyOxh8kYU1kfwlNXCDM5b8RY= Message-ID: <440a7ae5-7070-46d2-8644-3fc2fa6a707f@arm.com> Date: Mon, 27 Apr 2026 09:08:53 +0530 Precedence: bulk X-Mailing-List: linux-arch@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 1/3] vmalloc: add __GFP_SKIP_KASAN support To: Catalin Marinas Cc: arnd@arndb.de, kees@kernel.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, akpm@linux-foundation.org, david@kernel.org, urezki@gmail.com, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, ljs@kernel.org, Liam.Howlett@oracle.com, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, tglx@kernel.org, usama.anjum@arm.com, mathieu.desnoyers@efficios.com, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Ryan Roberts References: <20260424130157.3163009-1-dev.jain@arm.com> <20260424130157.3163009-2-dev.jain@arm.com> Content-Language: en-US From: Dev Jain In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 25/04/26 2:44 pm, Catalin Marinas wrote: > On Fri, Apr 24, 2026 at 06:31:55PM +0530, Dev Jain wrote: >> diff --git a/mm/vmalloc.c b/mm/vmalloc.c >> index b31b208f6ecb3..c94fcb2725b6b 100644 >> --- a/mm/vmalloc.c >> +++ b/mm/vmalloc.c >> @@ -3939,7 +3939,7 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, >> __GFP_NOFAIL | __GFP_ZERO |\ >> __GFP_NORETRY | __GFP_RETRY_MAYFAIL |\ >> GFP_NOFS | GFP_NOIO | GFP_KERNEL_ACCOUNT |\ >> - GFP_USER | __GFP_NOLOCKDEP) >> + GFP_USER | __GFP_NOLOCKDEP | __GFP_SKIP_KASAN) >> >> static gfp_t vmalloc_fix_flags(gfp_t flags) >> { >> @@ -3980,6 +3980,9 @@ static gfp_t vmalloc_fix_flags(gfp_t flags) >> * >> * %__GFP_NOWARN can be used to suppress failure messages. >> * >> + * %__GFP_SKIP_KASAN can be used to skip unpoisoning of mapped pages >> + * (when prot=%PAGE_KERNEL). > > I just realised, if we go with this flag for vmalloc(), there's also a > comment in gfp_types.h implying that pages are unpoisoned by > kasan_unpoison_vmalloc() instead. This is no longer the case with this > patch. > > A VM_SKIP_KASAN flag may have been nicer but we already have > THREADINFO_GFP and GFP_VMAP_STACK, so all those call sites would have to > be moved to call the lower-level __vmalloc_node_range(). Yep we were discussing this only on v2, and realized the wider cleanup is not trivial and should be made separately. But I should change the documentation of GFP_SKIP_KASAN to say that if it passed on to vmalloc then it will also skip unpoisoning. >