diff options
Diffstat (limited to 'kernel/bpf')
| -rw-r--r-- | kernel/bpf/helpers.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 0517e9a8fc7c..01052f8664eb 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1427,9 +1427,23 @@ static int bpf_async_update_prog_callback(struct bpf_async_cb *cb, return 0; } +static DEFINE_PER_CPU(struct bpf_async_cb *, async_cb_running); + static int bpf_async_schedule_op(struct bpf_async_cb *cb, enum bpf_async_op op, u64 nsec, u32 timer_mode) { + /* + * Do not schedule another operation on this cpu if it's in irq_work + * callback that is processing async_cmds queue. Otherwise the following + * loop is possible: + * bpf_timer_start() -> bpf_async_schedule_op() -> irq_work_queue(). + * irqrestore -> bpf_async_irq_worker() -> tracepoint -> bpf_timer_start(). + */ + if (this_cpu_read(async_cb_running) == cb) { + bpf_async_refcount_put(cb); + return -EDEADLK; + } + struct bpf_async_cmd *cmd = kmalloc_nolock(sizeof(*cmd), 0, NUMA_NO_NODE); if (!cmd) { @@ -1628,6 +1642,7 @@ static void bpf_async_irq_worker(struct irq_work *work) return; list = llist_reverse_order(list); + this_cpu_write(async_cb_running, cb); llist_for_each_safe(pos, n, list) { struct bpf_async_cmd *cmd; @@ -1635,6 +1650,7 @@ static void bpf_async_irq_worker(struct irq_work *work) bpf_async_process_op(cb, cmd->op, cmd->nsec, cmd->mode); kfree_nolock(cmd); } + this_cpu_write(async_cb_running, NULL); } static void bpf_async_cancel_and_free(struct bpf_async_kern *async) |