diff options
Diffstat (limited to 'kernel/bpf/helpers.c')
| -rw-r--r-- | kernel/bpf/helpers.c | 39 |
1 files changed, 23 insertions, 16 deletions
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index e46ac288a108..56b0c1f678ee 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1177,13 +1177,6 @@ BPF_CALL_3(bpf_timer_init, struct bpf_timer_kern *, timer, struct bpf_map *, map ret = -EBUSY; goto out; } - if (!atomic64_read(&map->usercnt)) { - /* maps with timers must be either held by user space - * or pinned in bpffs. - */ - ret = -EPERM; - goto out; - } /* allocate hrtimer via map_kmalloc to use memcg accounting */ t = bpf_map_kmalloc_node(map, sizeof(*t), GFP_ATOMIC, map->numa_node); if (!t) { @@ -1196,7 +1189,21 @@ BPF_CALL_3(bpf_timer_init, struct bpf_timer_kern *, timer, struct bpf_map *, map rcu_assign_pointer(t->callback_fn, NULL); hrtimer_init(&t->timer, clockid, HRTIMER_MODE_REL_SOFT); t->timer.function = bpf_timer_cb; - timer->timer = t; + WRITE_ONCE(timer->timer, t); + /* Guarantee the order between timer->timer and map->usercnt. So + * when there are concurrent uref release and bpf timer init, either + * bpf_timer_cancel_and_free() called by uref release reads a no-NULL + * timer or atomic64_read() below returns a zero usercnt. + */ + smp_mb(); + if (!atomic64_read(&map->usercnt)) { + /* maps with timers must be either held by user space + * or pinned in bpffs. + */ + WRITE_ONCE(timer->timer, NULL); + kfree(t); + ret = -EPERM; + } out: __bpf_spin_unlock_irqrestore(&timer->lock); return ret; @@ -1374,7 +1381,7 @@ void bpf_timer_cancel_and_free(void *val) /* The subsequent bpf_timer_start/cancel() helpers won't be able to use * this timer, since it won't be initialized. */ - timer->timer = NULL; + WRITE_ONCE(timer->timer, NULL); out: __bpf_spin_unlock_irqrestore(&timer->lock); if (!t) @@ -1886,9 +1893,7 @@ void bpf_rb_root_free(const struct btf_field *field, void *rb_root, } } -__diag_push(); -__diag_ignore_all("-Wmissing-prototypes", - "Global functions as their definitions will be in vmlinux BTF"); +__bpf_kfunc_start_defs(); __bpf_kfunc void *bpf_obj_new_impl(u64 local_type_id__k, void *meta__ign) { @@ -2505,7 +2510,7 @@ __bpf_kfunc void bpf_throw(u64 cookie) WARN(1, "A call to BPF exception callback should never return\n"); } -__diag_pop(); +__bpf_kfunc_end_defs(); BTF_SET8_START(generic_btf_ids) #ifdef CONFIG_KEXEC_CORE @@ -2564,15 +2569,17 @@ BTF_ID_FLAGS(func, bpf_iter_num_destroy, KF_ITER_DESTROY) BTF_ID_FLAGS(func, bpf_iter_task_vma_new, KF_ITER_NEW | KF_RCU) BTF_ID_FLAGS(func, bpf_iter_task_vma_next, KF_ITER_NEXT | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_iter_task_vma_destroy, KF_ITER_DESTROY) +#ifdef CONFIG_CGROUPS BTF_ID_FLAGS(func, bpf_iter_css_task_new, KF_ITER_NEW | KF_TRUSTED_ARGS) BTF_ID_FLAGS(func, bpf_iter_css_task_next, KF_ITER_NEXT | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_iter_css_task_destroy, KF_ITER_DESTROY) -BTF_ID_FLAGS(func, bpf_iter_task_new, KF_ITER_NEW | KF_TRUSTED_ARGS | KF_RCU_PROTECTED) -BTF_ID_FLAGS(func, bpf_iter_task_next, KF_ITER_NEXT | KF_RET_NULL) -BTF_ID_FLAGS(func, bpf_iter_task_destroy, KF_ITER_DESTROY) BTF_ID_FLAGS(func, bpf_iter_css_new, KF_ITER_NEW | KF_TRUSTED_ARGS | KF_RCU_PROTECTED) BTF_ID_FLAGS(func, bpf_iter_css_next, KF_ITER_NEXT | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_iter_css_destroy, KF_ITER_DESTROY) +#endif +BTF_ID_FLAGS(func, bpf_iter_task_new, KF_ITER_NEW | KF_TRUSTED_ARGS | KF_RCU_PROTECTED) +BTF_ID_FLAGS(func, bpf_iter_task_next, KF_ITER_NEXT | KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_iter_task_destroy, KF_ITER_DESTROY) BTF_ID_FLAGS(func, bpf_dynptr_adjust) BTF_ID_FLAGS(func, bpf_dynptr_is_null) BTF_ID_FLAGS(func, bpf_dynptr_is_rdonly) |