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| author | Yuntao Wang <ytcoode@gmail.com> | 2022-04-07 21:04:23 +0800 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2022-04-09 00:28:21 +0200 |
| commit | b45043192b3e481304062938a6561da2ceea46a6 (patch) | |
| tree | eae4d0e258db5d566fafb7aed8e6cee5bfa27b57 | |
| parent | 658d87687cd5a6c8762d1de8abee1e6792d8d71e (diff) | |
| download | linux-b45043192b3e481304062938a6561da2ceea46a6.tar.bz2 | |
bpf: Fix excessive memory allocation in stack_map_alloc()
The 'n_buckets * (value_size + sizeof(struct stack_map_bucket))' part of the
allocated memory for 'smap' is never used after the memlock accounting was
removed, thus get rid of it.
[ Note, Daniel:
Commit b936ca643ade ("bpf: rework memlock-based memory accounting for maps")
moved `cost += n_buckets * (value_size + sizeof(struct stack_map_bucket))`
up and therefore before the bpf_map_area_alloc() allocation, sigh. In a later
step commit c85d69135a91 ("bpf: move memory size checks to bpf_map_charge_init()"),
and the overflow checks of `cost >= U32_MAX - PAGE_SIZE` moved into
bpf_map_charge_init(). And then 370868107bf6 ("bpf: Eliminate rlimit-based
memory accounting for stackmap maps") finally removed the bpf_map_charge_init().
Anyway, the original code did the allocation same way as /after/ this fix. ]
Fixes: b936ca643ade ("bpf: rework memlock-based memory accounting for maps")
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220407130423.798386-1-ytcoode@gmail.com
| -rw-r--r-- | kernel/bpf/stackmap.c | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index 6131b4a19572..1dd5266fbebb 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -100,7 +100,6 @@ 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); - cost += n_buckets * (value_size + sizeof(struct stack_map_bucket)); smap = bpf_map_area_alloc(cost, bpf_map_attr_numa_node(attr)); if (!smap) return ERR_PTR(-ENOMEM); |