From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-lf1-f47.google.com (mail-lf1-f47.google.com [209.85.167.47]) (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 C8E873043BE for ; Wed, 6 May 2026 18:47:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.47 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778093249; cv=none; b=cxBpSN5H0LiPfLZmLgSoekTjED0GCH74N5xQPcm7NREppkoQ6J5yZ9w8B8jIcfuvuIUYiEvcxSrLrPHst5rQM9gFsGsV+kpXzYoxa8QL3Kqi1bKAsXk5QCLbDKlEZxCSpppU4vzBdvop0PkZdZscapbRKu9ZVw4qC0kDXojNRE8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778093249; c=relaxed/simple; bh=BO/0/WnfruM///+oF84S1w3cAw6thxlNQOaKYGGA1mY=; h=From:Date:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=crfB2YNAv0pSuQ2QI7Xs2mNgiigD7oE1gikQ0JjuwkTHfV3+S6HEPSUM8MRB6qJeqcyho7ZEIsjXdPEm4cJRNncl+mKZrrjCYsUYz57ah34taHDQfmJ9KGWRTrBHcItiMbP5p+5YsO6naYwv/xF0khzDU/zcHFEmtbVMcRE7+3M= 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=HUdczeff; arc=none smtp.client-ip=209.85.167.47 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="HUdczeff" Received: by mail-lf1-f47.google.com with SMTP id 2adb3069b0e04-5a4113ab355so6574904e87.1 for ; Wed, 06 May 2026 11:47:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1778093246; x=1778698046; 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=iffeP1fxOOkYpaGIpDPtCsG757023DZRgT4MFhCh+5k=; b=HUdczeffT0qqsdwdRdk07CKplR0TXAImt/aNCwyUybw2cVrfVlnfAw4c4xzIm7XBSR T6VFURse235uXVi2XT3TWmQB57C0RmSmZKgKTNJWiyXystFcUeXqqkaCXYDvQDs4DJ5p sfihDvduaBOXkEpsWxzBbDFAqLAfOf6K71Yb/7Am6OIUKsPKPgVpCv0rm68jqWUQuOTj XAeC1wGU0awHPuDdS9tBvsBfFurx529ALHOtttCqzdD/YatQrdL19cDZ5dwgCNlt5PcJ tcM1ZIomYD5dhv8gxoFs5skIma6Hx+YTPPm47e21JRYSjOtUhg4ryL8PipB7LxDAJRs/ VewA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1778093246; x=1778698046; 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=iffeP1fxOOkYpaGIpDPtCsG757023DZRgT4MFhCh+5k=; b=UYCm3C31I5gspxPEsqSAao9GHAeZavr9t8SlOEIQ/beXiDkiH6C/NLaraSGFA3CaiM LvIZ7OUDKtBCaHPDkxSH2IfJlhV+lFcz4ILGX2Xp8EDNae2ibR6gKTIaane0V7emvu6S AIKloaDbzBqsF4YpHIM8qaszOdo4tlwOaIuk3yyIg7/UKUpPZPmE9XSLuiIwLkDlURHY QPOh7qxbBbEYMAjc4+U8+YBVqhJbnaq4sx8EZ+iimYeLHuVCf8kKUHoizpQ09WOH44yH TPTZEa7I7Dld+C1stOARq0tRSdqJiaDHr5riOosJwg4iQqgbCafQ/BEl98TN86Cbb8Pj dG8A== X-Forwarded-Encrypted: i=1; AFNElJ/EoOOmGOQ1XTe+DNxKXGM7xeLg9/CHVVhx+P2lbqMkOeX4X5rSl5U/udwgL6Vf6W1MrdGd7S50TiB8+jU=@vger.kernel.org X-Gm-Message-State: AOJu0YyxIhSD8CW/6GZqFBpuT1ubDDu8j8GBWfJu9SahocQVmrozCylp xmM4jsIpMxvxEvcTxE8LCsFH0gPrkaq3LOH4rdXgK+NOiUW7xwnEC/9EgjHZXu0i X-Gm-Gg: AeBDievdeXZmcBlCrwWgdlmmn4gBTpBrJd6Il+S6o6wOVNAztnZYZH90FPsEHnZzaR0 GI4cESdl8+wcoDLbOvlDlub3r0VTJhRkEA7xmYq7q5doDCofLll9sy+0nNN5LUowRGsehsMmCzZ 6Iz1w/Dy4AyNPiMUurxmtbXMFJwfQepWABTnZb5RP/xhgYLAJvlF5JrGR/uA70la9Xf9Ghn8ow+ qsBeHVhkjHlL66Yspsbcmko37A6/MLRnH4/9WKQ9dbLS+bTO+AHIk6E5IFZKIhwx2sPNlQeO+TB 4pVdMzdXWBIpUzqTIkoM8iQdD2MmWhSD0Q31+l2BFeOM7aG3ddz431NRDdWZMP/MYasKvgsfZfV t/6q0ALiemwFKa+SAcplj4uE1PDZKs+3SvjBAectN7jT8TNZ7tlL9Osm/t2id5gKvgD1KACmEb1 zlQ69DUqHGk3LKTH464k1DzyNyu/jGQg== X-Received: by 2002:ac2:53a4:0:b0:5a8:896c:8989 with SMTP id 2adb3069b0e04-5a8896c8bffmr1165595e87.30.1778093245844; Wed, 06 May 2026 11:47:25 -0700 (PDT) Received: from pc636 ([2001:9b1:d5a0:a500:de96:9acf:5dca:ede4]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-5a865c8bed6sm4299484e87.31.2026.05.06.11.47.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 06 May 2026 11:47:25 -0700 (PDT) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Wed, 6 May 2026 20:47:24 +0200 To: shivamkalra98@zohomail.in Cc: Andrew Morton , Uladzislau Rezki , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Alice Ryhl , Danilo Krummrich Subject: Re: [PATCH v12 2/5] mm/vmalloc: use physical page count for vrealloc() grow-in-place check Message-ID: References: <20260428-vmalloc-shrink-v12-0-3c18c9172eb1@zohomail.in> <20260428-vmalloc-shrink-v12-2-3c18c9172eb1@zohomail.in> Precedence: bulk X-Mailing-List: linux-kernel@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: <20260428-vmalloc-shrink-v12-2-3c18c9172eb1@zohomail.in> On Tue, Apr 28, 2026 at 01:54:17AM +0530, Shivam Kalra via B4 Relay wrote: > From: Shivam Kalra > > Update the grow-in-place check in vrealloc() to compare the requested size > against the actual physical page count (vm->nr_pages) rather than the > virtual area size (alloced_size, derived from get_vm_area_size()). > > Currently both values are equivalent, but the upcoming vrealloc() shrink > functionality will free pages without reducing the virtual reservation > size. After such a shrink, the old alloced_size-based comparison would > incorrectly allow a grow-in-place operation to succeed and attempt to > access freed pages. Switch to vm->nr_pages now so the check remains > correct once shrink support is added. > > Signed-off-by: Shivam Kalra > --- > mm/vmalloc.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 1073abb6094e..9cb3e287a1e8 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -4338,6 +4338,12 @@ void *vrealloc_node_align_noprof(const void *p, size_t size, unsigned long align > if (unlikely(flags & __GFP_THISNODE) && nid != NUMA_NO_NODE && > nid != page_to_nid(vmalloc_to_page(p))) > goto need_realloc; > + } else { > + /* > + * If p is NULL, vrealloc behaves exactly like vmalloc. > + * Skip the shrink and in-place grow paths. > + */ > + goto need_realloc; > } > > /* > @@ -4356,7 +4362,7 @@ void *vrealloc_node_align_noprof(const void *p, size_t size, unsigned long align > /* > * We already have the bytes available in the allocation; use them. > */ > - if (size <= alloced_size) { > + if (size <= vm->nr_pages << PAGE_SHIFT) { > /* > Maybe we should consider Fujunjie approach and borrow his idea to shrink VA also? In that case, we do not need to switch to vm->nr_pages? And we do not need [PATCH v12 3/5] mm/vmalloc: use physical page count in vread_iter() ? -- Uladzislau Rezki