linux-kernel - Re: [PATCH v2 2/9] ARM: traps: use get_kernel_nofault instead of set

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Message-ID: <20200919052746.GG30063@infradead.org>
Date:   Sat, 19 Sep 2020 06:27:46 +0100
From:   Christoph Hellwig <hch@...radead.org>
To:     Arnd Bergmann <arnd@...db.de>
Cc:     Christoph Hellwig <hch@...radead.org>,
        Russell King <linux@...linux.org.uk>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-arch@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH v2 2/9] ARM: traps: use get_kernel_nofault instead of
 set_fs()

On Fri, Sep 18, 2020 at 02:46:17PM +0200, Arnd Bergmann wrote:
> ARM uses set_fs() and __get_user() to allow the stack dumping code to
> access possibly invalid pointers carefully. These can be changed to the
> simpler get_kernel_nofault(), and allow the eventual removal of set_fs().
> 
> dump_instr() will print either kernel or user space pointers,
> depending on how it was called. For dump_mem(), I assume we are only
> interested in kernel pointers, and the only time that this is called
> with user_mode(regs)==true is when the regs themselves are unreliable
> as a result of the condition that caused the trap.
> 
> Signed-off-by: Arnd Bergmann <arnd@...db.de>

Looks good,

Reviewed-by: Christoph Hellwig <hch@....de>