From 3f2189e4f77b7a3e979d143dc4ff586488c7e8a5 Mon Sep 17 00:00:00 2001 From: Hou Tao Date: Fri, 20 Oct 2023 21:31:59 +0800 Subject: bpf: Use pcpu_alloc_size() in bpf_mem_free{_rcu}() For bpf_global_percpu_ma, the pointer passed to bpf_mem_free_rcu() is allocated by kmalloc() and its size is fixed (16-bytes on x86-64). So no matter which cache allocates the dynamic per-cpu area, on x86-64 cache[2] will always be used to free the per-cpu area. Fix the unbalance by checking whether the bpf memory allocator is per-cpu or not and use pcpu_alloc_size() instead of ksize() to find the correct cache for per-cpu free. Signed-off-by: Hou Tao Link: https://lore.kernel.org/r/20231020133202.4043247-5-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/memalloc.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) (limited to 'kernel/bpf/memalloc.c') diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c index 776bdf5ffd80..5308e386380a 100644 --- a/kernel/bpf/memalloc.c +++ b/kernel/bpf/memalloc.c @@ -525,6 +525,7 @@ int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, bool percpu) /* room for llist_node and per-cpu pointer */ if (percpu) percpu_size = LLIST_NODE_SZ + sizeof(void *); + ma->percpu = percpu; if (size) { pc = __alloc_percpu_gfp(sizeof(*pc), 8, GFP_KERNEL); @@ -874,6 +875,17 @@ void notrace *bpf_mem_alloc(struct bpf_mem_alloc *ma, size_t size) return !ret ? NULL : ret + LLIST_NODE_SZ; } +static notrace int bpf_mem_free_idx(void *ptr, bool percpu) +{ + size_t size; + + if (percpu) + size = pcpu_alloc_size(*((void **)ptr)); + else + size = ksize(ptr - LLIST_NODE_SZ); + return bpf_mem_cache_idx(size); +} + void notrace bpf_mem_free(struct bpf_mem_alloc *ma, void *ptr) { int idx; @@ -881,7 +893,7 @@ void notrace bpf_mem_free(struct bpf_mem_alloc *ma, void *ptr) if (!ptr) return; - idx = bpf_mem_cache_idx(ksize(ptr - LLIST_NODE_SZ)); + idx = bpf_mem_free_idx(ptr, ma->percpu); if (idx < 0) return; @@ -895,7 +907,7 @@ void notrace bpf_mem_free_rcu(struct bpf_mem_alloc *ma, void *ptr) if (!ptr) return; - idx = bpf_mem_cache_idx(ksize(ptr - LLIST_NODE_SZ)); + idx = bpf_mem_free_idx(ptr, ma->percpu); if (idx < 0) return; -- cgit v1.2.3