RE: [PATCH] proc: use vmalloc for our kernel buffer

David Laight
2020-08-13T16:19:35Z

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 ...' ?

David

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