diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 50aba113ef9d..1b32b9f2491f 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -948,8 +948,8 @@ static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_ins void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns, bool was_classic) { unsigned int nbits = BPF_PROG_SIZE_TO_NBITS(size); - struct bpf_prog_pack *pack; - unsigned long pos; + struct bpf_prog_pack *pack, *fallback_pack = NULL; + unsigned long pos, fallback_pos = 0; void *ptr = NULL; mutex_lock(&pack_mutex); @@ -981,8 +981,29 @@ void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns, bool list_for_each_entry(pack, &pack_list, list) { pos = bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0, nbits, 0); - if (pos < BPF_PROG_CHUNK_COUNT) + if (pos >= BPF_PROG_CHUNK_COUNT) + continue; + /* Flush not enabled, use any pack */ + if (!static_branch_unlikely(&bpf_pred_flush_enabled)) goto found_free_area; + /* + * cBPF reuse of a dirty pack triggers a flush, so prefer a + * clean pack for cBPF. eBPF never flushes, so pick the first + * free pack, dirty or clean. + */ + if (!was_classic || !pack->arch_flush_needed) + goto found_free_area; + if (!fallback_pack) { + fallback_pack = pack; + fallback_pos = pos; + } + } + + /* No preferred pack found */ + if (fallback_pack) { + pack = fallback_pack; + pos = fallback_pos; + goto found_free_area; } pack = alloc_new_pack(bpf_fill_ill_insns);