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Diffstat (limited to 'include/linux/bpf.h')
-rw-r--r--include/linux/bpf.h41
1 files changed, 36 insertions, 5 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 49b1a70e12c8..6015a4daf118 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -859,7 +859,7 @@ struct bpf_prog_array_item {
struct bpf_prog_array {
struct rcu_head rcu;
- struct bpf_prog_array_item items[0];
+ struct bpf_prog_array_item items[];
};
struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags);
@@ -885,7 +885,7 @@ int bpf_prog_array_copy(struct bpf_prog_array *old_array,
struct bpf_prog *_prog; \
struct bpf_prog_array *_array; \
u32 _ret = 1; \
- preempt_disable(); \
+ migrate_disable(); \
rcu_read_lock(); \
_array = rcu_dereference(array); \
if (unlikely(check_non_null && !_array))\
@@ -898,7 +898,7 @@ int bpf_prog_array_copy(struct bpf_prog_array *old_array,
} \
_out: \
rcu_read_unlock(); \
- preempt_enable(); \
+ migrate_enable(); \
_ret; \
})
@@ -932,7 +932,7 @@ _out: \
u32 ret; \
u32 _ret = 1; \
u32 _cn = 0; \
- preempt_disable(); \
+ migrate_disable(); \
rcu_read_lock(); \
_array = rcu_dereference(array); \
_item = &_array->items[0]; \
@@ -944,7 +944,7 @@ _out: \
_item++; \
} \
rcu_read_unlock(); \
- preempt_enable(); \
+ migrate_enable(); \
if (_ret) \
_ret = (_cn ? NET_XMIT_CN : NET_XMIT_SUCCESS); \
else \
@@ -961,6 +961,36 @@ _out: \
#ifdef CONFIG_BPF_SYSCALL
DECLARE_PER_CPU(int, bpf_prog_active);
+/*
+ * Block execution of BPF programs attached to instrumentation (perf,
+ * kprobes, tracepoints) to prevent deadlocks on map operations as any of
+ * these events can happen inside a region which holds a map bucket lock
+ * and can deadlock on it.
+ *
+ * Use the preemption safe inc/dec variants on RT because migrate disable
+ * is preemptible on RT and preemption in the middle of the RMW operation
+ * might lead to inconsistent state. Use the raw variants for non RT
+ * kernels as migrate_disable() maps to preempt_disable() so the slightly
+ * more expensive save operation can be avoided.
+ */
+static inline void bpf_disable_instrumentation(void)
+{
+ migrate_disable();
+ if (IS_ENABLED(CONFIG_PREEMPT_RT))
+ this_cpu_inc(bpf_prog_active);
+ else
+ __this_cpu_inc(bpf_prog_active);
+}
+
+static inline void bpf_enable_instrumentation(void)
+{
+ if (IS_ENABLED(CONFIG_PREEMPT_RT))
+ this_cpu_dec(bpf_prog_active);
+ else
+ __this_cpu_dec(bpf_prog_active);
+ migrate_enable();
+}
+
extern const struct file_operations bpf_map_fops;
extern const struct file_operations bpf_prog_fops;
@@ -993,6 +1023,7 @@ void __bpf_free_used_maps(struct bpf_prog_aux *aux,
void bpf_prog_free_id(struct bpf_prog *prog, bool do_idr_lock);
void bpf_map_free_id(struct bpf_map *map, bool do_idr_lock);
+struct bpf_map *bpf_map_get(u32 ufd);
struct bpf_map *bpf_map_get_with_uref(u32 ufd);
struct bpf_map *__bpf_map_get(struct fd f);
void bpf_map_inc(struct bpf_map *map);