From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f73.google.com (mail-wm1-f73.google.com [209.85.128.73]) (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 EA68739A7FB for ; Tue, 24 Mar 2026 11:01:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774350117; cv=none; b=k531A9vKyZ5r7E0Ncp5RgIx5+xVqMR+d/TDb1DgSSTVNSFr7dZLR4qL7ILl2w5R0ZUATSVjcVglYRuIJfjOt4Z4eb1sFiDoFS42A3c4w/sBG7VmR0hJDpG6b7A2AH0quXp8pPfTBF6Ubem218R8I6YLOXmUVIiHMulcJZop57oQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774350117; c=relaxed/simple; bh=kv8inrTiCzjbcGmjafC4cdz6oVzuBZB/yNZxHeJx50A=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=V47NiWaDvjGD4HBwHLUFwee2S+kR5wpG7Xdr1bdBTx6zgtoXuLj4v/MJ6PkMnNAW+cx1pmvH39RNR8Ldif1jwoV4j9VaMo5DVDXQf2F+mk6AMGPiu2X0+0hcLTDki/H8YnrjpyqV85Qt0zpjwuwm9JhBIf2BKcluqLRlImZiiIQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--aliceryhl.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=qhAQSGA8; arc=none smtp.client-ip=209.85.128.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--aliceryhl.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="qhAQSGA8" Received: by mail-wm1-f73.google.com with SMTP id 5b1f17b1804b1-4853466655dso12471075e9.3 for ; Tue, 24 Mar 2026 04:01:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1774350114; x=1774954914; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=abr86o86MPJz2Br8J+2IIJwCu13i3DMn7PEURQveLEk=; b=qhAQSGA8tYKA9snfodadmUCwsKbx6ADFijl4P+12/YpxRNFKMjL/yj4X8QZl7rAUh7 RgFY/VPB8JC63IkPuVqjE8sWOEVjs5BBbgZ00bLIiR0y66B5TsxoEvwrPolJ1UXIDrF+ uHrD9pwdxLfHVCgEMB4e3Kn3eno29Pzi7D+W3WFyfwgY6ZkNuZIxfsoVwnuEV+nj5vU8 u0xwi2Wz28kIAsWSR0Z7ZQyO944eGLXNwclpAqnSaODTi1bmQVrvWsKuYByJr/GT+LPi iYl9GhVKdTCWbYXUQ0PH5XBHm2Ij+4lLNn/Hmh6GA+D5xjkKXaTCiGI3Rn/HpDy+FFCM u/Cg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774350114; x=1774954914; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=abr86o86MPJz2Br8J+2IIJwCu13i3DMn7PEURQveLEk=; b=n+VUhMRZjVPFYd2vclmw1Wy6NiMF5sT1uxgPCtiVG5ZI4kRILSaYmBTpo4gaRq4f0O b5Wpixy3FQ9NPeqq/6gDwNhJZHmohVqr2PAtpI9Vot/Vx45FV1ivxzaND+jdnmPL8Nk6 0nAPXOMiM6aBU1zArP85AKhaRdWSP7FQ9B5qWSdnkaospkGa/0sUmrGSvumoUrfO9m1c E6nrRQfI4syM5ysSpYRlGevvNd61fSZu0V2/ls7hOt2wSIf+/t8t09/q1g+exCudwY5V znpHhn2inBOqioE0o51iHZ8uq5q5vyP7HKCIS+5ZMEMbfnnycmnboZd99ttMxDsnNfcV 2jGg== X-Forwarded-Encrypted: i=1; AJvYcCWuvRDJ3vI9+rk1w0Ph+VukErkCqEGCSD7ytUuMgFRKv23XT/pMD+yGLMmIYogA48dhokMRuE+oApMGzGQ=@vger.kernel.org X-Gm-Message-State: AOJu0YzYrj1YbulPqsjuayC0swyv7KQ4nSRCRkxoyhc0iSweVfNWwxCC se+QOIsYMSXlvcNRG1LDsknfHhtoIVPGwrUqBW1P1OSIMm3R+HcwPvBL2ZopHS+v92eRw7wSgNQ gLCqmDlDysn8zV9mQUw== X-Received: from wmsk23-n2.prod.google.com ([2002:a05:600d:8497:20b0:487:f69:2be4]) (user=aliceryhl job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:4705:b0:46e:4e6d:79f4 with SMTP id 5b1f17b1804b1-486fee0e2ecmr212740435e9.15.1774350114065; Tue, 24 Mar 2026 04:01:54 -0700 (PDT) Date: Tue, 24 Mar 2026 11:01:53 +0000 In-Reply-To: <20260324-vmalloc-shrink-v7-2-c0e62b8e5d83@zohomail.in> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260324-vmalloc-shrink-v7-0-c0e62b8e5d83@zohomail.in> <20260324-vmalloc-shrink-v7-2-c0e62b8e5d83@zohomail.in> Message-ID: Subject: Re: [PATCH v7 2/6] mm/vmalloc: fix vrealloc() grow-in-place check From: Alice Ryhl To: shivamkalra98@zohomail.in Cc: Andrew Morton , Uladzislau Rezki , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Danilo Krummrich Content-Type: text/plain; charset="utf-8" On Tue, Mar 24, 2026 at 03:30:27PM +0530, Shivam Kalra via B4 Relay wrote: > From: Shivam Kalra > > Fix 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()). > > The virtual reservation size (get_vm_area_size()) does not decrease when > pages are freed during a shrink operation. Consequently, without this fix, > a subsequent grow-in-place operation after a shrink would incorrectly > succeed and attempt to access freed pages. Correcting this check is a > prerequisite for the upcoming vrealloc() shrink functionality. > > Signed-off-by: Shivam Kalra This commit is titled 'fix', but is it actually a fix for a bug that exists today? Or is it just a refactor to support the follow-up shrinking logic? Alice