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| author | YiFei Zhu <zhuyifei@google.com> | 2020-09-15 16:45:39 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-09-15 18:28:27 -0700 |
| commit | 984fe94f94756dacb3c8cc52904a23adf9e04da1 (patch) | |
| tree | 70c58720e1166b35434d2033abcdda63e915f6d3 /kernel/bpf/core.c | |
| parent | d317b0a8acfc4b126858e4cdadb03338d22f8ce0 (diff) | |
| download | linux-984fe94f94756dacb3c8cc52904a23adf9e04da1.tar.gz linux-984fe94f94756dacb3c8cc52904a23adf9e04da1.tar.bz2 linux-984fe94f94756dacb3c8cc52904a23adf9e04da1.zip | |
bpf: Mutex protect used_maps array and count
To support modifying the used_maps array, we use a mutex to protect
the use of the counter and the array. The mutex is initialized right
after the prog aux is allocated, and destroyed right before prog
aux is freed. This way we guarantee it's initialized for both cBPF
and eBPF.
Signed-off-by: YiFei Zhu <zhuyifei@google.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Cc: YiFei Zhu <zhuyifei1999@gmail.com>
Link: https://lore.kernel.org/bpf/20200915234543.3220146-2-sdf@google.com
Diffstat (limited to 'kernel/bpf/core.c')
| -rw-r--r-- | kernel/bpf/core.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index ed0b3578867c..2a20c2833996 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -98,6 +98,7 @@ struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flag fp->jit_requested = ebpf_jit_enabled(); INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode); + mutex_init(&fp->aux->used_maps_mutex); return fp; } @@ -253,6 +254,7 @@ struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, void __bpf_prog_free(struct bpf_prog *fp) { if (fp->aux) { + mutex_destroy(&fp->aux->used_maps_mutex); free_percpu(fp->aux->stats); kfree(fp->aux->poke_tab); kfree(fp->aux); @@ -1747,8 +1749,9 @@ bool bpf_prog_array_compatible(struct bpf_array *array, static int bpf_check_tail_call(const struct bpf_prog *fp) { struct bpf_prog_aux *aux = fp->aux; - int i; + int i, ret = 0; + mutex_lock(&aux->used_maps_mutex); for (i = 0; i < aux->used_map_cnt; i++) { struct bpf_map *map = aux->used_maps[i]; struct bpf_array *array; @@ -1757,11 +1760,15 @@ static int bpf_check_tail_call(const struct bpf_prog *fp) continue; array = container_of(map, struct bpf_array, map); - if (!bpf_prog_array_compatible(array, fp)) - return -EINVAL; + if (!bpf_prog_array_compatible(array, fp)) { + ret = -EINVAL; + goto out; + } } - return 0; +out: + mutex_unlock(&aux->used_maps_mutex); + return ret; } static void bpf_prog_select_func(struct bpf_prog *fp) |