diff mbox series

[bpf-next,1/2] bpf: fix bpf_prog_pack for multi-node setup

Message ID 20220321180009.1944482-2-song@kernel.org (mailing list archive)
State Accepted
Commit 96805674e5624b3c79780a2b41c7a3d6bc38dc76
Delegated to: BPF
Headers show
Series fixes for bpf_prog_pack | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for bpf-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 9 this patch: 9
netdev/cc_maintainers fail 1 blamed authors not CCed: songliubraving@fb.com; 5 maintainers not CCed: songliubraving@fb.com yhs@fb.com john.fastabend@gmail.com kafai@fb.com kpsingh@kernel.org
netdev/build_clang success Errors and warnings before: 18 this patch: 18
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 14 this patch: 14
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 28 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-next-PR success PR summary

Commit Message

Song Liu March 21, 2022, 6 p.m. UTC 
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 <song@kernel.org>
---
 kernel/bpf/core.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)
diff mbox series

Patch

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) {