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bpf: Fix bpf_prog_pack for multi-node setup

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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: ef078600ee ("bpf: Select proper size for bpf_prog_pack")
Reported-by: syzbot+c946805b5ce6ab87df0b@syzkaller.appspotmail.com
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220321180009.1944482-2-song@kernel.org
This commit is contained in:
Song Liu 2022-03-21 11:00:08 -07:00 committed by Alexei Starovoitov
parent d56c9fe6a0
commit 96805674e5
1 changed files with 7 additions and 2 deletions
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9
kernel/bpf/core.c
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@ -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) {