Re: [PATCH] wireless: mwifiex: fix double free

[Brian Norris]

On Sun, Oct 4, 2020 at 6:19 AM <trix@xxxxxxxxxx> wrote:
>
> From: Tom Rix <trix@xxxxxxxxxx>
>
> clang static analysis reports this problem:
>
> sdio.c:2403:3: warning: Attempt to free released memory
>         kfree(card->mpa_rx.buf);
>         ^~~~~~~~~~~~~~~~~~~~~~~

That's some interesting static analysis for a compiler.

> When mwifiex_init_sdio() fails in its first call to
> mwifiex_alloc_sdio_mpa_buffer, it falls back to calling it
> again.  If the second alloc of mpa_tx.buf fails, the error
> handler will try to free the old, previously freed mpa_rx.buf.
> Reviewing the code, it looks like a second double free would
> happen with mwifiex_cleanup_sdio().
>
> So set both pointers to NULL when they are freed.
>
> Fixes: 5e6e3a92b9a4 ("wireless: mwifiex: initial commit for Marvell mwifiex driver")
> Signed-off-by: Tom Rix <trix@xxxxxxxxxx>

For whatever it's worth:

Reviewed-by: Brian Norris <briannorris@xxxxxxxxxxxx>