bpf: Let bpf_prog_pack_free handle any pointer

Currently, bpf_prog_pack_free only can only free pointer to struct
bpf_binary_header, which is not flexible. Add a size argument to
bpf_prog_pack_free so that it can handle any pointer.

Signed-off-by: Song Liu <song@kernel.org>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>  # on s390x
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20231206224054.492250-2-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/include/linux/filter.h b/include/linux/filter.h
index 1435460..12d907f 100644 (file)
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -1067,7 +1067,7 @@ struct bpf_binary_header *
 bpf_jit_binary_pack_hdr(const struct bpf_prog *fp);
 
 void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns);
-void bpf_prog_pack_free(struct bpf_binary_header *hdr);
+void bpf_prog_pack_free(void *ptr, u32 size);
 
 static inline bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp)
 {

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index ced511f..c34513d 100644 (file)
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -928,20 +928,20 @@ out:
        return ptr;
 }
 
-void bpf_prog_pack_free(struct bpf_binary_header *hdr)
+void bpf_prog_pack_free(void *ptr, u32 size)
 {
        struct bpf_prog_pack *pack = NULL, *tmp;
        unsigned int nbits;
        unsigned long pos;
 
        mutex_lock(&pack_mutex);
-       if (hdr->size > BPF_PROG_PACK_SIZE) {
-               bpf_jit_free_exec(hdr);
+       if (size > BPF_PROG_PACK_SIZE) {
+               bpf_jit_free_exec(ptr);
                goto out;
        }
 
        list_for_each_entry(tmp, &pack_list, list) {
-               if ((void *)hdr >= tmp->ptr && (tmp->ptr + BPF_PROG_PACK_SIZE) > (void *)hdr) {
+               if (ptr >= tmp->ptr && (tmp->ptr + BPF_PROG_PACK_SIZE) > ptr) {
                        pack = tmp;
                        break;
                }
@@ -950,10 +950,10 @@ void bpf_prog_pack_free(struct bpf_binary_header *hdr)
        if (WARN_ONCE(!pack, "bpf_prog_pack bug\n"))
                goto out;
 
-       nbits = BPF_PROG_SIZE_TO_NBITS(hdr->size);
-       pos = ((unsigned long)hdr - (unsigned long)pack->ptr) >> BPF_PROG_CHUNK_SHIFT;
+       nbits = BPF_PROG_SIZE_TO_NBITS(size);
+       pos = ((unsigned long)ptr - (unsigned long)pack->ptr) >> BPF_PROG_CHUNK_SHIFT;
 
-       WARN_ONCE(bpf_arch_text_invalidate(hdr, hdr->size),
+       WARN_ONCE(bpf_arch_text_invalidate(ptr, size),
                  "bpf_prog_pack bug: missing bpf_arch_text_invalidate?\n");
 
        bitmap_clear(pack->bitmap, pos, nbits);
@@ -1100,8 +1100,7 @@ bpf_jit_binary_pack_alloc(unsigned int proglen, u8 **image_ptr,
 
        *rw_header = kvmalloc(size, GFP_KERNEL);
        if (!*rw_header) {
-               bpf_arch_text_copy(&ro_header->size, &size, sizeof(size));
-               bpf_prog_pack_free(ro_header);
+               bpf_prog_pack_free(ro_header, size);
                bpf_jit_uncharge_modmem(size);
                return NULL;
        }
@@ -1132,7 +1131,7 @@ int bpf_jit_binary_pack_finalize(struct bpf_prog *prog,
        kvfree(rw_header);
 
        if (IS_ERR(ptr)) {
-               bpf_prog_pack_free(ro_header);
+               bpf_prog_pack_free(ro_header, ro_header->size);
                return PTR_ERR(ptr);
        }
        return 0;
@@ -1153,7 +1152,7 @@ void bpf_jit_binary_pack_free(struct bpf_binary_header *ro_header,
 {
        u32 size = ro_header->size;
 
-       bpf_prog_pack_free(ro_header);
+       bpf_prog_pack_free(ro_header, size);
        kvfree(rw_header);
        bpf_jit_uncharge_modmem(size);
 }

diff --git a/kernel/bpf/dispatcher.c b/kernel/bpf/dispatcher.c
index fa3e922..56760fc 100644 (file)
--- a/kernel/bpf/dispatcher.c
+++ b/kernel/bpf/dispatcher.c
@@ -150,10 +150,7 @@ void bpf_dispatcher_change_prog(struct bpf_dispatcher *d, struct bpf_prog *from,
                        goto out;
                d->rw_image = bpf_jit_alloc_exec(PAGE_SIZE);
                if (!d->rw_image) {
-                       u32 size = PAGE_SIZE;
-
-                       bpf_arch_text_copy(d->image, &size, sizeof(size));
-                       bpf_prog_pack_free((struct bpf_binary_header *)d->image);
+                       bpf_prog_pack_free(d->image, PAGE_SIZE);
                        d->image = NULL;
                        goto out;
                }