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Date:   Wed, 28 Apr 2021 15:03:39 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Arusekk <arek_koz@o2.pl>
Cc:     Christoph Hellwig <hch@lst.de>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        Alexey Dobriyan <adobriyan@gmail.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH] proc: Use seq_read_iter where possible
Message-ID: <20210428130339.GA30329@lst.de>
References: <20210427183414.12499-1-arek_koz@o2.pl> <20210428061259.GA5084@lst.de> <9905352.nUPlyArG6x@swift.dev.arusekk.pl>
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On Wed, Apr 28, 2021 at 03:02:13PM +0200, Arusekk wrote:
> The instructions at the entry point of the executable being inspected.
> The flow of the tool:
> - parse ELF headers of the binary to be inspected,
> - locate its entry point position in the file,
> - write short code at the location (this short code has used sendfile so far),
> - execute the patched binary,
> - parse the output and extract information about the relevant mappings.
> This can be seen as equivalent to setting LD_TRACE_LOADED_OBJECTS,
> but also works for static binaries, and is a bit safer.
> 
> The problem was reported at:
> https://github.com/Gallopsled/pwntools/issues/1871

Oh, this patches just the userspace binarz, ok.

> > Linus did object to blindly switching over all instances.
> 
> I know, I read that, but I thought that pointing a real use case, combined 
> with the new interface being used all throughout the other code, might be 
> convincing.
> I would be happy with only changing the f_ops of /proc/.../maps, even if only 
> on MMU-enabled systems, but I thought that consistence would be better.
> This is my first time contributing to Linux, so I am very sorry for any wrong 
> assumptions, and glad to learn more.

Unless Linus changed his mind just patching the file you care about for
now seems like the best idea.