From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E7C41152DF7 for ; Mon, 13 May 2024 13:30:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715607007; cv=none; b=t8NkjG9Z0QODFV3X081dAz+qEHoxCvNsw2gkxt3LT/ZOf2eevYoDkF64rJ5/KgyKHB2GzmMszwBeXUEuvFSi4YZhV0m3QJ93IkhiNtADXBNfLXul04f1bpn7RwM2AyY9vyt00c+p3OphG04qFqu2sxABzCpiK8TAE4yJ5LZEUDY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715607007; c=relaxed/simple; bh=fdQj5tpm1DVEdbOjzBNuiDD2iIHzRTPcRVUBvlbI/Ic=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=krZTJEAMhtQs8wgdyucrfV7hX7Knoxs6qn0ROGVe7JmGFCotovNUPpBIhIgU+cYAENbeMzOecc/wlE5aacrGvYtB7hs4P2OyESoo5pA2TRBGLL/W42DJqQq3lfQ0ZhaYAhtWkTRzf8FZe1VGxgCQy/fqtrwJ0zrIzA/JPxZPPF0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=wwZwD5dq; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="wwZwD5dq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6886BC113CC; Mon, 13 May 2024 13:30:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1715607006; bh=fdQj5tpm1DVEdbOjzBNuiDD2iIHzRTPcRVUBvlbI/Ic=; h=Subject:To:Cc:From:Date:From; b=wwZwD5dqreraQvSMAS+xElk/udAFDNzbng/Ul4IZdcpwYK1oRf0nEbH9yU4RrZeKg ueqdu6n487uE21QP4i+pl9bYv8NgVHxMpqnr7Dfl5iDqEkdMfzrinzCDtBO9bOWJ9M oRf5SjhmARJzvQkyxIRlpM3OVvwyVC2fTLNxWXa8= Subject: FAILED: patch "[PATCH] maple_tree: fix mas_empty_area_rev() null pointer dereference" failed to apply to 6.12-stable tree To: Liam.Howlett@oracle.com,akpm@linux-foundation.org,fleischermarius@gmail.com,sidhartha.kumar@oracle.com,stable@vger.kernel.org Cc: From: Date: Mon, 13 May 2024 15:29:45 +0200 Message-ID: <2024051344-squeamish-runaround-c445@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x 955a923d2809803980ff574270f81510112be9cf # git commit -s git send-email --to '' --in-reply-to '2024051344-squeamish-runaround-c445@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 955a923d2809803980ff574270f81510112be9cf Mon Sep 17 00:00:00 2001 From: "Liam R. Howlett" Date: Mon, 22 Apr 2024 16:33:49 -0400 Subject: [PATCH] maple_tree: fix mas_empty_area_rev() null pointer dereference Currently the code calls mas_start() followed by mas_data_end() if the maple state is MA_START, but mas_start() may return with the maple state node == NULL. This will lead to a null pointer dereference when checking information in the NULL node, which is done in mas_data_end(). Avoid setting the offset if there is no node by waiting until after the maple state is checked for an empty or single entry state. A user could trigger the events to cause a kernel oops by unmapping all vmas to produce an empty maple tree, then mapping a vma that would cause the scenario described above. Link: https://lkml.kernel.org/r/20240422203349.2418465-1-Liam.Howlett@oracle.com Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Liam R. Howlett Reported-by: Marius Fleischer Closes: https://lore.kernel.org/lkml/CAJg=8jyuSxDL6XvqEXY_66M20psRK2J53oBTP+fjV5xpW2-R6w@mail.gmail.com/ Link: https://lore.kernel.org/lkml/CAJg=8jyuSxDL6XvqEXY_66M20psRK2J53oBTP+fjV5xpW2-R6w@mail.gmail.com/ Tested-by: Marius Fleischer Tested-by: Sidhartha Kumar Cc: Signed-off-by: Andrew Morton diff --git a/lib/maple_tree.c b/lib/maple_tree.c index 55e1b35bf877..2d7d27e6ae3c 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -5109,18 +5109,18 @@ int mas_empty_area_rev(struct ma_state *mas, unsigned long min, if (size == 0 || max - min < size - 1) return -EINVAL; - if (mas_is_start(mas)) { + if (mas_is_start(mas)) mas_start(mas); - mas->offset = mas_data_end(mas); - } else if (mas->offset >= 2) { - mas->offset -= 2; - } else if (!mas_rewind_node(mas)) { + else if ((mas->offset < 2) && (!mas_rewind_node(mas))) return -EBUSY; - } - /* Empty set. */ - if (mas_is_none(mas) || mas_is_ptr(mas)) + if (unlikely(mas_is_none(mas) || mas_is_ptr(mas))) return mas_sparse_area(mas, min, max, size, false); + else if (mas->offset >= 2) + mas->offset -= 2; + else + mas->offset = mas_data_end(mas); + /* The start of the window can only be within these values. */ mas->index = min;