From: Yuntao Wang ytcoode@gmail.com
stable inclusion from stable-v5.10.121 commit 6c0a8c771a71b13b998327e1cff52526634ce47a category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5L6CQ
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ Upstream commit b45043192b3e481304062938a6561da2ceea46a6 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Acked-by: Xie XiuQi xiexiuqi@huawei.com --- kernel/bpf/stackmap.c | 1 - 1 file changed, 1 deletion(-)
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index 22ef49037579..dac3d3db419e 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -121,7 +121,6 @@ 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)); err = bpf_map_charge_init(&mem, cost); if (err) return ERR_PTR(err);