Commit e804587e authored Jun 14, 2022 by Yuntao Wang Committed by Greg Kroah-Hartman Jun 22, 2022

bpf: Fix incorrect memory charge cost calculation in stack_map_alloc()



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@vger.kernel.org> # 5.4.y
Cc: <stable@vger.kernel.org> # 5.10.y
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent f91da317

kernel/bpf/stackmap.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -117,7 +117,8 @@ static struct bpf_map stack_map_alloc(union bpf_attr attr)
		return ERR_PTR(-E2BIG);

		cost = n_buckets * sizeof(struct stack_map_bucket ) + sizeof(smap);
		err = bpf_map_charge_init(&mem, cost);
		err = bpf_map_charge_init(&mem, cost + attr->max_entries *
		(sizeof(struct stack_map_bucket) + (u64)value_size));
		if (err)
		return ERR_PTR(err);