Re: [PATCH] bpf: Fix incorrect memory charge cost calculation in stack_map_alloc()

[Greg KH]

On Tue, Jun 14, 2022 at 10:26:22PM +0800, Yuntao Wang wrote:
> commit b45043192b3e481304062938a6561da2ceea46a6 upstream.
> 
> This is a backport of the original upstream patch for 5.4/5.10.
> 
> The original upstream patch has been applied to 5.4/5.10 branches, which
> simply removed the line:
> 
>   cost += n_buckets * (value_size + sizeof(struct stack_map_bucket));
> 
> This is correct for upstream branch but incorrect for 5.4/5.10 branches,
> as the 5.4/5.10 branches do not have the commit 370868107bf6 ("bpf:
> Eliminate rlimit-based memory accounting for stackmap maps"), so the
> bpf_map_charge_init() function has not been removed.
> 
> Currently the bpf_map_charge_init() function in 5.4/5.10 branches takes a
> wrong memory charge cost, the
> 
>   attr->max_entries * (sizeof(struct stack_map_bucket) + (u64)value_size))
> 
> part is missing, let's fix it.
> 
> Cc: <stable@xxxxxxxxxxxxxxx> # 5.4.y
> Cc: <stable@xxxxxxxxxxxxxxx> # 5.10.y
> Signed-off-by: Yuntao Wang <ytcoode@xxxxxxxxx>
> ---
> Note that the original upstream patch is currently applied to
> linux-stable-rc/linux-5.4.y branch, not linux/linux-5.4.y, this patch
> depends on that patch.

Now queued up, thanks.

greg k-h