From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-lj1-f171.google.com (mail-lj1-f171.google.com [209.85.208.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4FBA430E844 for ; Tue, 18 Nov 2025 09:34:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763458483; cv=none; b=UW+Hx1qXD3lmFVd7HDgTwVEZaCCRRpV2eGkKlfOb1QcPXfClMEceeV2kI7u6/372Tt5ngU8Oqn3QyXQ0Mksvw5WkUiYbdouInokZUtR9OovzWb53u6uzQgipYRLP4t+OGS/c4JVZrl3WbpO7mxNTPmTPe7U7C29FdK3MjIDF5kI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763458483; c=relaxed/simple; bh=yIPnM3n4I0PjAXIK5w2dmHOKPXHY68UV/yyBRwOcZow=; h=From:Date:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=hp9nYpXExLCiEKC7B0mDOwrsvkfrzNTF0rp37fgVEV3BmuFj6Utj/KLpM5AMSb+SiZEPMZ5w4tlxnRgXTAYH57TX4bb2PmjeRwq9Loe8XyVUyx9/R0apVuQvESWUhjdMNtTYnVjnJ2etlGtbid+U2JIvd4blFXOjiyX5Wxay+hw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=DDp8FMjI; arc=none smtp.client-ip=209.85.208.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="DDp8FMjI" Received: by mail-lj1-f171.google.com with SMTP id 38308e7fff4ca-37b99da107cso47320841fa.1 for ; Tue, 18 Nov 2025 01:34:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1763458479; x=1764063279; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:from:to:cc:subject:date:message-id:reply-to; bh=SqcgtmKu36yGOEI8Pko6WxzeIhQjSBh9Rhu3pqJUFvQ=; b=DDp8FMjIZ1ENtVlp1JLIiOs3XbW424Jo1oFO5bHNZGIxdUFVP/YGA/EMuCFrFwcqPv kFftuTXpHlEec3Qf3i1Up/078GiD0oGOsKrwk7m+6S624XURdUyz77R4duQwEmM8TBot dfBElJALViOLOWqd2hPo9OmEDMt+gLHIoKhk+XWv+HpsrXNFvuRQFp5sup7WeJX+tolO /V94g4kw9gavm3rYZ+T4kGQn9gYgdivCCCVtW2PTZ1TeOpZQKSkygLLnNjsPXxgYGNyp 261w0RXP6KK55446jQ8zArsjDaAMXs6SvHaeXuuOKAeYthxqbCcs4xTGGQL3f9PqPmI8 Pmxg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1763458479; x=1764063279; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=SqcgtmKu36yGOEI8Pko6WxzeIhQjSBh9Rhu3pqJUFvQ=; b=oC/LU2nAH3ATs+d29yWU3dVXJasRoBEMih7rWC2Bq6FG6xb9WEE1PZuH0QI8AbE+kd 1wGmnosHtmv/43GaAbYAbf6Ux4QRXfIP35aiocyf40a0Bp3733u2dM2DV8pkGz080QBT 1MzWQug6nAWvv222zMcdPSHxrLhcTwBJskDa0Bjlbx4KNd42nN7xObPd+nXyU+vsh2WV Sva5CUlXRQ0KqKnmuOqjLhh0x119EiiVk7Ri0KgEaWqA8SYMRpjhZxz0mN+XhWa2Sqta aQw0Z9iHj8YpxMmpBGWruTRmFS4gOO5vy+/TSRXl26ypzVP7cjl/ZaiFU/wxeK8vVEJV zp5A== X-Forwarded-Encrypted: i=1; AJvYcCVbXqDBGWuJ/+f1iecI7T4WSeNXyhWPxapmVX5GrofEkD55yophZhc+EVZa42PYRTgO1Dc=@vger.kernel.org X-Gm-Message-State: AOJu0Yz+Upf9xUck7ia04btKH3SrvTnT44XK4TzVDU4Fp7itdBhIpO5y vs5t/Pc9AcpArSC3MFgXaDZNAkbUWVQItZKtJkJh3oQXphhOK9gutCCE X-Gm-Gg: ASbGncsz52F8QXumkNl02lI80gE2EpmRQd7F30Y5JLpmNVoOKS8x/MVljQUcyFPxSAO 2SEFU/yiq5DuBdKA8IxPBUX0pm0a44evHoRcoZ3EJtPTp3HqgBIM48t9CBuKCC0ax3UzfCspPOh uc9EoSsMAqPsEWN/Aj6mjB1xOUlwgXwWQutrwsHTskoM/P2ZeYEXszPRzC0/TjtV8M/BrNgh7QT Gh7G1XmV1LoJNiDyW1gagc+b7cvdjP9PIg821LoADAGBbKz9pnitTYCnh5Qs0G6+lkLID3I6F3U dKINIAnNnYB6Rv3tdr1PWYHnWcHvYv4nJApcHJO78bteFM+/bHahdO6RwAC3WYOO6Fzuadw2s30 GqG71qj151kYjp7W9T26Wd4LrrJkmN5tYkKR07C31GIR8UEi3vRhcOFMwvLehT95X41oUYueost FvXSQbTqZ9VvHG+R3IPPPD1FWLWkB08pe6rIEGx18v X-Google-Smtp-Source: AGHT+IGkdRAnCzdans0QSjjqeWINwfYXF9anLqr0LKbujqMjX6imLeve1k1SvIKyWvJPxmfqbrqEhg== X-Received: by 2002:a05:6512:3d1e:b0:593:4a:a5d3 with SMTP id 2adb3069b0e04-595841ff545mr5445493e87.22.1763458479117; Tue, 18 Nov 2025 01:34:39 -0800 (PST) Received: from pc636 (host-90-233-212-127.mobileonline.telia.com. [90.233.212.127]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-595804004aasm3859270e87.60.2025.11.18.01.34.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 18 Nov 2025 01:34:38 -0800 (PST) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Tue, 18 Nov 2025 10:34:36 +0100 To: "Vishal Moola (Oracle)" Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, bpf@vger.kernel.org, Uladzislau Rezki , Christoph Hellwig , Andrew Morton , Christoph Hellwig Subject: Re: [PATCH v3 1/4] mm/vmalloc: warn on invalid vmalloc gfp flags Message-ID: References: <20251117173530.43293-1-vishal.moola@gmail.com> <20251117173530.43293-2-vishal.moola@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251117173530.43293-2-vishal.moola@gmail.com> On Mon, Nov 17, 2025 at 09:35:27AM -0800, Vishal Moola (Oracle) wrote: > Vmalloc explicitly supports a list of flags, but we never enforce them. > vmalloc has been trying to handle unsupported flags by clearing and > setting flags wherever necessary. This is messy and makes the code > harder to understand, when we could simply check for a supported input > immediately instead. > > Define a helper mask and function telling callers they have passed in > invalid flags, and clear those unsupported vmalloc flags. > > Suggested-by: Christoph Hellwig > Signed-off-by: Vishal Moola (Oracle) > Reviewed-by: Christoph Hellwig > --- > mm/vmalloc.c | 26 ++++++++++++++++++++++++++ > 1 file changed, 26 insertions(+) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 0832f944544c..5dc467c6cab4 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -3911,6 +3911,28 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, > return NULL; > } > > +/* > + * See __vmalloc_node_range() for a clear list of supported vmalloc flags. > + * This gfp lists all flags currently passed through vmalloc. Currently, > + * __GFP_ZERO is used by BPF and __GFP_NORETRY is used by percpu. Both drm > + * and BPF also use GFP_USER. Additionally, various users pass > + * GFP_KERNEL_ACCOUNT. > + */ > +#define GFP_VMALLOC_SUPPORTED (GFP_KERNEL | GFP_ATOMIC | GFP_NOWAIT |\ > + __GFP_NOFAIL | __GFP_ZERO | __GFP_NORETRY |\ > + GFP_NOFS | GFP_NOIO | GFP_KERNEL_ACCOUNT |\ > + GFP_USER) > + > +static gfp_t vmalloc_fix_flags(gfp_t flags) > +{ > + gfp_t invalid_mask = flags & ~GFP_VMALLOC_SUPPORTED; > + > + flags &= GFP_VMALLOC_SUPPORTED; > + WARN(1, "Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n", > + invalid_mask, &invalid_mask, flags, &flags); > + return flags; > +} > + > /** > * __vmalloc_node_range - allocate virtually contiguous memory > * @size: allocation size > @@ -4092,6 +4114,8 @@ EXPORT_SYMBOL_GPL(__vmalloc_node_noprof); > > void *__vmalloc_noprof(unsigned long size, gfp_t gfp_mask) > { > + if (unlikely(gfp_mask & ~GFP_VMALLOC_SUPPORTED)) > + gfp_mask = vmalloc_fix_flags(gfp_mask); > return __vmalloc_node_noprof(size, 1, gfp_mask, NUMA_NO_NODE, > __builtin_return_address(0)); > } > @@ -4131,6 +4155,8 @@ EXPORT_SYMBOL(vmalloc_noprof); > */ > void *vmalloc_huge_node_noprof(unsigned long size, gfp_t gfp_mask, int node) > { > + if (unlikely(gfp_mask & ~GFP_VMALLOC_SUPPORTED)) > + gfp_mask = vmalloc_fix_flags(gfp_mask); > return __vmalloc_node_range_noprof(size, 1, VMALLOC_START, VMALLOC_END, > gfp_mask, PAGE_KERNEL, VM_ALLOW_HUGE_VMAP, > node, __builtin_return_address(0)); > -- > 2.51.1 > Reviewed-by: "Uladzislau Rezki (Sony)" -- Uladzislau Rezki