Re: [PATCH v6] soc: aspeed: lpc-snoop: Fix usercopy overflow in snoop_file_read
From: Andrew Jeffery
Date: Wed Jul 22 2026 - 08:56:18 EST
On Fri, 12 Jun 2026 19:07:43 +0000, Karthikeyan KS wrote:
> put_fifo_with_discard() acts as both producer and consumer on the kfifo:
> it calls kfifo_skip() (advances out) and kfifo_put() (advances in) from
> the IRQ handler without synchronizing with snoop_file_read(), which also
> consumes via kfifo_to_user(). On SMP systems this concurrent access can
> leave (in - out) larger than the ring buffer, so __kfifo_to_user()'s clamp
> to (in - out) is ineffective and kfifo_copy_to_user() can attempt a
> copy_to_user() past the kmalloc-2k backing store:
>
> [...]
Thanks, I've applied this to the BMC tree.
--
Andrew Jeffery <andrew@xxxxxxxxxxxxxxxxxxxx>