[PATCH bpf-next 0/2] fixes for bpf_prog_pack

[PATCH bpf-next 0/2] fixes for bpf_prog_pack

[Song Liu]

Two fixes for issues reported by syzbot and kernel test robot.

Song Liu (2):
  bpf: fix bpf_prog_pack for multi-node setup
  bpf: fix bpf_prog_pack when PMU_SIZE is not defined

 kernel/bpf/core.c | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

--
2.30.2

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

[Song Liu]

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 --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) {
-- 
2.30.2

[PATCH bpf-next 2/2] bpf: fix bpf_prog_pack when PMU_SIZE is not defined

[Song Liu]

PMD_SIZE is not available in some special config, e.g. ARCH=arm with
CONFIG_MMU=n. Use bpf_prog_pack of PAGE_SIZE in these cases.

Fixes: ef078600eec2 ("bpf: Select proper size for bpf_prog_pack")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Song Liu <song@kernel.org>
---
 kernel/bpf/core.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index f6b20fcbeb24..13e9dbeeedf3 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -840,12 +840,23 @@ static int bpf_prog_chunk_count(void)
 static DEFINE_MUTEX(pack_mutex);
 static LIST_HEAD(pack_list);
 
+/* PMD_SIZE is not available in some special config, e.g. ARCH=arm with
+ * CONFIG_MMU=n. Use PAGE_SIZE in these cases.
+ */
+#ifdef PMD_SIZE
+#define BPF_HPAGE_SIZE PMD_SIZE
+#define BPF_HPAGE_MASK PMD_MASK
+#else
+#define BPF_HPAGE_SIZE PAGE_SIZE
+#define BPF_HPAGE_MASK PAGE_MASK
+#endif
+
 static size_t select_bpf_prog_pack_size(void)
 {
 	size_t size;
 	void *ptr;
 
-	size = PMD_SIZE * num_online_nodes();
+	size = BPF_HPAGE_SIZE * num_online_nodes();
 	ptr = module_alloc(size);
 
 	/* Test whether we can get huge pages. If not just use PAGE_SIZE
@@ -855,7 +866,7 @@ static size_t select_bpf_prog_pack_size(void)
 		size = PAGE_SIZE;
 		bpf_prog_pack_mask = PAGE_MASK;
 	} else {
-		bpf_prog_pack_mask = PMD_MASK;
+		bpf_prog_pack_mask = BPF_HPAGE_MASK;
 	}
 
 	vfree(ptr);
-- 
2.30.2

Re: [PATCH bpf-next 0/2] fixes for bpf_prog_pack

[patchwork-bot+netdevbpf]

Hello:

This series was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <ast@kernel.org>:

On Mon, 21 Mar 2022 11:00:07 -0700 you wrote:
> Two fixes for issues reported by syzbot and kernel test robot.
> 
> Song Liu (2):
>   bpf: fix bpf_prog_pack for multi-node setup
>   bpf: fix bpf_prog_pack when PMU_SIZE is not defined
> 
>  kernel/bpf/core.c | 22 +++++++++++++++++++---
>  1 file changed, 19 insertions(+), 3 deletions(-)
> 
> [...]

Here is the summary with links:
  - [bpf-next,1/2] bpf: fix bpf_prog_pack for multi-node setup
    https://git.kernel.org/bpf/bpf-next/c/96805674e562
  - [bpf-next,2/2] bpf: fix bpf_prog_pack when PMU_SIZE is not defined
    https://git.kernel.org/bpf/bpf-next/c/e581094167be

You are awesome, thank you!
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