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 E23081AAE08; Wed, 20 Nov 2024 13:00:22 +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=1732107623; cv=none; b=Wr2I8peMh0ihScbTkAjRjeT/SJZDett4oALCMaJyuDs3RcjivtbImEzO8SXLq8ZGof3zzMFQ4PLzeIaTuqe0YLEpur8m07IQtkM1GsQKE6li3TQWn/+VJayM4q6wIQwpBHkMFpDePXRF02cUP58+qh9AOhQ6i0js7bMtuCH5QYo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732107623; c=relaxed/simple; bh=ZXDnJ8nkPKCcRjAyC5h022ywf4OCaAQrUFfrsKBqWt0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=cnGMSkUnzwpJ9Z9w6Lk1ZwgQNGvAm59UEYeSrN0wDK8Hh/uHRY+XAbP6TrlnFfhfran20PfxOwrlSM2+lQvPJ2w8vuf1dHuu7hJoOQ1z53fGxJRupbijx1e9y4xQjSPdbck4YTdycU3P+1jlX5rz2XSdf8uQOCcLryENbJqHUjc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=nQSXjnAW; 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="nQSXjnAW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5A050C4CECD; Wed, 20 Nov 2024 13:00:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1732107622; bh=ZXDnJ8nkPKCcRjAyC5h022ywf4OCaAQrUFfrsKBqWt0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nQSXjnAWZfYo1bQqtzbd35RiNYMpljc4q57Ibr2CEyMLRcatEJIfKUJAfZWSqu/Kd AVzTG5y1EPhGCkTRhIvSs5oFI917VJItwKpFd4W5/YYYZz8vMZpW0KjSopm+/20TG3 juVw9Knu4w3/JGYPQcNqhj/tAsF/HoZqY4KLkxss= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Lorenzo Stoakes , Jann Horn , Vlastimil Babka , "Liam R. Howlett" , Andreas Larsson , Catalin Marinas , "David S. Miller" , Helge Deller , "James E.J. Bottomley" , Linus Torvalds , Mark Brown , Peter Xu , Will Deacon , Andrew Morton Subject: [PATCH 6.6 76/82] mm: unconditionally close VMAs on error Date: Wed, 20 Nov 2024 13:57:26 +0100 Message-ID: <20241120125631.329604062@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241120125629.623666563@linuxfoundation.org> References: <20241120125629.623666563@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Lorenzo Stoakes [ Upstream commit 4080ef1579b2413435413988d14ac8c68e4d42c8 ] Incorrect invocation of VMA callbacks when the VMA is no longer in a consistent state is bug prone and risky to perform. With regards to the important vm_ops->close() callback We have gone to great lengths to try to track whether or not we ought to close VMAs. Rather than doing so and risking making a mistake somewhere, instead unconditionally close and reset vma->vm_ops to an empty dummy operations set with a NULL .close operator. We introduce a new function to do so - vma_close() - and simplify existing vms logic which tracked whether we needed to close or not. This simplifies the logic, avoids incorrect double-calling of the .close() callback and allows us to update error paths to simply call vma_close() unconditionally - making VMA closure idempotent. Link: https://lkml.kernel.org/r/28e89dda96f68c505cb6f8e9fc9b57c3e9f74b42.1730224667.git.lorenzo.stoakes@oracle.com Fixes: deb0f6562884 ("mm/mmap: undo ->mmap() when arch_validate_flags() fails") Signed-off-by: Lorenzo Stoakes Reported-by: Jann Horn Reviewed-by: Vlastimil Babka Reviewed-by: Liam R. Howlett Reviewed-by: Jann Horn Cc: Andreas Larsson Cc: Catalin Marinas Cc: David S. Miller Cc: Helge Deller Cc: James E.J. Bottomley Cc: Linus Torvalds Cc: Mark Brown Cc: Peter Xu Cc: Will Deacon Cc: Signed-off-by: Andrew Morton Signed-off-by: Lorenzo Stoakes Signed-off-by: Greg Kroah-Hartman --- mm/internal.h | 18 ++++++++++++++++++ mm/mmap.c | 9 +++------ mm/nommu.c | 3 +-- 3 files changed, 22 insertions(+), 8 deletions(-) --- a/mm/internal.h +++ b/mm/internal.h @@ -110,6 +110,24 @@ static inline int mmap_file(struct file return err; } +/* + * If the VMA has a close hook then close it, and since closing it might leave + * it in an inconsistent state which makes the use of any hooks suspect, clear + * them down by installing dummy empty hooks. + */ +static inline void vma_close(struct vm_area_struct *vma) +{ + if (vma->vm_ops && vma->vm_ops->close) { + vma->vm_ops->close(vma); + + /* + * The mapping is in an inconsistent state, and no further hooks + * may be invoked upon it. + */ + vma->vm_ops = &vma_dummy_vm_ops; + } +} + void __acct_reclaim_writeback(pg_data_t *pgdat, struct folio *folio, int nr_throttled); static inline void acct_reclaim_writeback(struct folio *folio) --- a/mm/mmap.c +++ b/mm/mmap.c @@ -137,8 +137,7 @@ void unlink_file_vma(struct vm_area_stru static void remove_vma(struct vm_area_struct *vma, bool unreachable) { might_sleep(); - if (vma->vm_ops && vma->vm_ops->close) - vma->vm_ops->close(vma); + vma_close(vma); if (vma->vm_file) fput(vma->vm_file); mpol_put(vma_policy(vma)); @@ -2899,8 +2898,7 @@ expanded: return addr; close_and_free_vma: - if (file && vma->vm_ops && vma->vm_ops->close) - vma->vm_ops->close(vma); + vma_close(vma); if (file || vma->vm_file) { unmap_and_free_vma: @@ -3392,8 +3390,7 @@ struct vm_area_struct *copy_vma(struct v return new_vma; out_vma_link: - if (new_vma->vm_ops && new_vma->vm_ops->close) - new_vma->vm_ops->close(new_vma); + vma_close(new_vma); if (new_vma->vm_file) fput(new_vma->vm_file); --- a/mm/nommu.c +++ b/mm/nommu.c @@ -600,8 +600,7 @@ static int delete_vma_from_mm(struct vm_ */ static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma) { - if (vma->vm_ops && vma->vm_ops->close) - vma->vm_ops->close(vma); + vma_close(vma); if (vma->vm_file) fput(vma->vm_file); put_nommu_region(vma->vm_region);