On Mon, 2023-03-06 at 15:33 -0600, Nathan Lynch via B4 Relay wrote:
> From: Nathan Lynch <nath...@linux.ibm.com>
>
> Using memcpy() isn't safe when buf is identical to rtas_err_buf,
> which
> can happen during boot before slab is up. Full context which may not
> be obvious from the diff:
>
> if (altbuf) {
> buf = altbuf;
> } else {
> buf = rtas_err_buf;
> if (slab_is_available())
> buf = kmalloc(RTAS_ERROR_LOG_MAX,
> GFP_ATOMIC);
> }
> if (buf)
> memcpy(buf, rtas_err_buf, RTAS_ERROR_LOG_MAX);
>
> This was found by inspection and I'm not aware of it causing problems
> in practice. It appears to have been introduced by commit
> 033ef338b6e0 ("powerpc: Merge rtas.c into arch/powerpc/kernel"); the
> old ppc64 version of this code did not have this problem.
>
> Use memmove() instead.
>
> Fixes: 033ef338b6e0 ("powerpc: Merge rtas.c into
> arch/powerpc/kernel")
> Signed-off-by: Nathan Lynch <nath...@linux.ibm.com>
Reviewed-by: Andrew Donnellan <a...@linux.ibm.com>
--
Andrew Donnellan OzLabs, ADL Canberra
a...@linux.ibm.com IBM Australia Limited
