Messages in this thread | | | Date | Thu, 26 Oct 2023 09:03:10 +0200 | From | Sascha Hauer <> | Subject | Re: [PATCH] net: Do not break out of sk_stream_wait_memory() with TIF_NOTIFY_SIGNAL |
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On Tue, Oct 24, 2023 at 03:56:17PM +0200, Paolo Abeni wrote: > On Mon, 2023-10-23 at 14:13 +0200, Sascha Hauer wrote: > > It can happen that a socket sends the remaining data at close() time. > > With io_uring and KTLS it can happen that sk_stream_wait_memory() bails > > out with -512 (-ERESTARTSYS) because TIF_NOTIFY_SIGNAL is set for the > > current task. This flag has been set in io_req_normal_work_add() by > > calling task_work_add(). > > > > It seems signal_pending() is too broad, so this patch replaces it with > > task_sigpending(), thus ignoring the TIF_NOTIFY_SIGNAL flag. > > This looks dangerous, at best. Other possible legit users setting > TIF_NOTIFY_SIGNAL will be broken. > > Can't you instead clear TIF_NOTIFY_SIGNAL in io_run_task_work() ?
I don't have an idea how io_run_task_work() comes into play here, but it seems it already clears TIF_NOTIFY_SIGNAL:
static inline int io_run_task_work(void) { /* * Always check-and-clear the task_work notification signal. With how * signaling works for task_work, we can find it set with nothing to * run. We need to clear it for that case, like get_signal() does. */ if (test_thread_flag(TIF_NOTIFY_SIGNAL)) clear_notify_signal(); ... }
Sascha
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