From 96805674e5624b3c79780a2b41c7a3d6bc38dc76 Mon Sep 17 00:00:00 2001 From: Song Liu Date: Mon, 21 Mar 2022 11:00:08 -0700 Subject: [PATCH] bpf: Fix bpf_prog_pack for multi-node setup module_alloc requires num_online_nodes * PMD_SIZE to allocate huge pages. bpf_prog_pack uses pack of size num_online_nodes * PMD_SIZE. OTOH, module_alloc returns addresses that are PMD_SIZE aligned (instead of num_online_nodes * PMD_SIZE aligned). Therefore, PMD_MASK should be used to calculate pack_ptr in bpf_prog_pack_free(). Fixes: ef078600eec2 ("bpf: Select proper size for bpf_prog_pack") Reported-by: syzbot+c946805b5ce6ab87df0b@syzkaller.appspotmail.com Signed-off-by: Song Liu Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20220321180009.1944482-2-song@kernel.org --- kernel/bpf/core.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 9d661e07e77c..f6b20fcbeb24 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -829,6 +829,7 @@ struct bpf_prog_pack { #define BPF_PROG_SIZE_TO_NBITS(size) (round_up(size, BPF_PROG_CHUNK_SIZE) / BPF_PROG_CHUNK_SIZE) static size_t bpf_prog_pack_size = -1; +static size_t bpf_prog_pack_mask = -1; static int bpf_prog_chunk_count(void) { @@ -850,8 +851,12 @@ static size_t select_bpf_prog_pack_size(void) /* Test whether we can get huge pages. If not just use PAGE_SIZE * packs. */ - if (!ptr || !is_vm_area_hugepages(ptr)) + if (!ptr || !is_vm_area_hugepages(ptr)) { size = PAGE_SIZE; + bpf_prog_pack_mask = PAGE_MASK; + } else { + bpf_prog_pack_mask = PMD_MASK; + } vfree(ptr); return size; @@ -935,7 +940,7 @@ static void bpf_prog_pack_free(struct bpf_binary_header *hdr) goto out; } - pack_ptr = (void *)((unsigned long)hdr & ~(bpf_prog_pack_size - 1)); + pack_ptr = (void *)((unsigned long)hdr & bpf_prog_pack_mask); list_for_each_entry(tmp, &pack_list, list) { if (tmp->ptr == pack_ptr) { -- 2.34.1