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Date:   Thu, 13 Aug 2020 16:19:27 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Josef Bacik' <>, "" <>,
        "" <>,
        "" <>,
        "" <>,
        "" <>
Subject: RE: [PATCH] proc: use vmalloc for our kernel buffer

From: Josef Bacik
> Sent: 13 August 2020 15:53
>   sysctl: pass kernel pointers to ->proc_handler
> we have been pre-allocating a buffer to copy the data from the proc
> handlers into, and then copying that to userspace.  The problem is this
> just blind kmalloc()'s the buffer size passed in from the read, which in
> the case of our 'cat' binary was 64kib.  Order-4 allocations are not
> awesome, and since we can potentially allocate up to our maximum order,
> use vmalloc for these buffers.

What happens if I run 'dd bs=16M ...' ?


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