linux-kernel - Re: [PATCH v2 1/4] selftest/vm: verify mmap addr in mremap

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Message-ID: <ff3db00d-3e18-8168-9f7d-d91a5591c7f2@linuxfoundation.org>
Date:   Thu, 21 Apr 2022 13:31:32 -0600
From:   Shuah Khan <skhan@...uxfoundation.org>
To:     Sidhartha Kumar <sidhartha.kumar@...cle.com>, shuah@...nel.org,
        akpm@...ux-foundation.org
Cc:     linux-mm@...ck.org, linux-kselftest@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Shuah Khan <skhan@...uxfoundation.org>
Subject: Re: [PATCH v2 1/4] selftest/vm: verify mmap addr in mremap_test

On 4/20/22 3:57 PM, Sidhartha Kumar wrote:
> Avoid calling mmap with requested addresses that are less than the system's
> mmap_min_addr. When run as root, mmap returns EACCES when trying to map
> addresses < mmap_min_addr. This is not one of the error codes for the
> condition to retry the mmap in the test. Rather than arbitrarily retrying
> on EACCES, don't attempt an mmap until addr > vm.mmap_min_addr.
> 
> Add a munmap call after an alignment check as the mappings are retained
> after the retry and can reach the vm.max_map_count sysctl.
> 
> Signed-off-by: Sidhartha Kumar <sidhartha.kumar@...cle.com>
> ---
> v2:
> -change comment for description of get_mmap_min_addr()
> -fix commit message formatting
> 

Thank you.

Reviewed-by: Shuah Khan <skhan@...uxfoundation.org>

Andrew, please let me know if you would like me to take this
through kselftest tree.

thanks,
-- Shuah