diff options
| -rw-r--r-- | kernel/trace/bpf_trace.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 195f78db9bda..5465e7eba238 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -823,6 +823,7 @@ const struct bpf_func_proto bpf_task_pt_regs_proto = { struct send_signal_irq_work { struct irq_work irq_work; + /* The claim: NULL marks the slot free for the next caller. */ struct task_struct *task; u32 sig; enum pid_type type; @@ -842,6 +843,8 @@ static void do_bpf_send_signal(struct irq_work *entry) group_send_sig_info(work->sig, siginfo, work->task, work->type); put_task_struct(work->task); + /* Release once the fields are consumed. */ + smp_store_release(&work->task, NULL); } static int bpf_send_signal_common(u32 sig, enum pid_type type, struct task_struct *task, u64 value) @@ -885,14 +888,14 @@ static int bpf_send_signal_common(u32 sig, enum pid_type type, struct task_struc return -EINVAL; work = this_cpu_ptr(&send_signal_work); - if (irq_work_is_busy(&work->irq_work)) + if (cmpxchg(&work->task, NULL, task)) return -EBUSY; /* Add the current task, which is the target of sending signal, * to the irq_work. The current task may change when queued * irq works get executed. */ - work->task = get_task_struct(task); + get_task_struct(task); work->has_siginfo = siginfo == &info; if (work->has_siginfo) copy_siginfo(&work->info, &info); |