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From: Christoph Hellwig <hch@infradead.org>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Arnd Bergmann <arnd@kernel.org>,
	linux-arch@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
	Christoph Hellwig <hch@infradead.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Andrew Morton <akpm@linux-foundation.org>,
	Borislav Petkov <bp@alien8.de>, Brian Gerst <brgerst@gmail.com>,
	Ingo Molnar <mingo@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	linux-kernel@vger.kernel.org, Linux-MM <linux-mm@kvack.org>,
	kexec@lists.infradead.org
Subject: Re: [PATCH v3 1/4] kexec: simplify compat_sys_kexec_load
Date: Tue, 18 May 2021 07:40:29 +0100	[thread overview]
Message-ID: <YKNhXQ883lRbqQGA@infradead.org> (raw)
In-Reply-To: <m1y2cc3d97.fsf@fess.ebiederm.org>

On Mon, May 17, 2021 at 10:57:24PM -0500, Eric W. Biederman wrote:
> We open ourselves up to bugs whenever we lie to the type system.
> 
> Skimming through the code it looks like it should be possible
> to not need the in_compat_syscall and the casts to the wrong
> type by changing the order of the code a little bit.

What kind of bug do you expect?  We must only copy from user addresses
once anyway.  I've never seen bugs due the use of in_compat_syscall,
but plenty due to cruft code trying to avoid it.

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  reply	other threads:[~2021-05-18  6:42 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-17 20:33 [PATCH v3 0/4] compat: remove compat_alloc_user_space callers Arnd Bergmann
2021-05-17 20:33 ` [PATCH v3 1/4] kexec: simplify compat_sys_kexec_load Arnd Bergmann
2021-05-18  3:57   ` Eric W. Biederman
2021-05-18  6:40     ` Christoph Hellwig [this message]
2021-05-18  7:44       ` Arnd Bergmann
2021-05-18  6:38   ` Christoph Hellwig
2021-05-18  7:47     ` Arnd Bergmann
2021-05-18 13:41   ` Eric W. Biederman
2021-05-18 14:05     ` Arnd Bergmann
2021-05-18 14:17       ` Arnd Bergmann
2021-05-18 16:01         ` Eric W. Biederman
2021-05-18 22:45         ` Eric W. Biederman
2021-05-19  9:55           ` Arnd Bergmann
2021-05-18 20:47   ` David Laight
2021-05-17 20:33 ` [PATCH v3 2/4] mm: simplify compat_sys_move_pages Arnd Bergmann
2021-05-18  6:42   ` Christoph Hellwig
2021-05-18 20:49   ` David Laight
2021-05-19 13:41     ` Arnd Bergmann
2021-05-17 20:33 ` [PATCH v3 3/4] mm: simplify compat numa syscalls Arnd Bergmann
2021-05-18  6:52   ` Christoph Hellwig
2021-05-17 20:33 ` [PATCH v3 4/4] compat: remove some compat entry points Arnd Bergmann
2021-05-18  6:55   ` Christoph Hellwig
2021-05-19 20:33   ` Thomas Gleixner
2021-05-19 21:00     ` Arnd Bergmann
2021-05-20  9:21       ` Arnd Bergmann

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