Re: [PATCH][v2] proc: use vmalloc for our kernel buffer

From: Josef Bacik
Date: Thu Aug 13 2020 - 13:36:18 EST

On 8/13/20 1:31 PM, Al Viro wrote:
On Thu, Aug 13, 2020 at 01:19:18PM -0400, Josef Bacik wrote:

in sunrpc proc_dodebug() turns into
left -= snprintf(buffer, left, "0x%04x\n",
left + 1, that is.

*(unsigned int *) table->data);
and that's not the only example.

We wouldn't even need the extra +1 part, since we're only copying in how
much the user wants anyway, we could just go ahead and convert this to

left -= snprintf(buffer, left, "0x%04x\n", *(unsigned int *) table->data);

and be fine, right? Or am I misunderstanding what you're looking for? Thanks,

snprintf() always produces a NUL-terminated string. And if you are passing 7 as
len, you want 0xf0ad\n to be copied to user. For that you need 8 passed to
snprintf, and 8-byte buffer given to it.

Right, gotcha. I'll rig that up and see how it looks. I'd recommend looking through what I do with a fine tooth comb, I'm obviously not batting 1000 today. Thanks,