Messages in this thread | | | Subject | Re: [PATCH] NFC: llcp: fix nfc_llcp_send_ui_frame() lockup | From | Eric Dumazet <> | Date | Mon, 25 Jun 2018 23:44:22 -0700 |
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On 06/25/2018 10:12 PM, Sergey Senozhatsky wrote: > On (06/26/18 07:07), Dmitry Vyukov wrote: > [..] >>> #include <net/nfc/nfc.h> >>> @@ -755,7 +756,8 @@ int nfc_llcp_send_ui_frame(struct nfc_llcp_sock *sock, u8 ssap, u8 dsap, >>> pdu = nfc_alloc_send_skb(sock->dev, &sock->sk, MSG_DONTWAIT, >>> frag_len + LLCP_HEADER_SIZE, &err); >>> if (pdu == NULL) { >>> - pr_err("Could not allocate PDU\n"); >>> + pr_err_ratelimited("Could not allocate PDU\n"); >>> + cond_resched(); >>> continue; >>> } >> >> >> But this thread is still in an infinite (unkillable?) loop? If yes, we >> are waiting for the next syzbot report ;) > > The loop is still infinite, correct, but we have a preemption point now. > Sure, net people can come with a much better solution, I'll be happy to > scratch my patch. >
This can not be the right solution, think about current thread being real time, cond_resched() might be a nop.
We should probably not loop at all, or not use MSG_DONTWAIT.
(And remove this useless "Could not allocate PDU" message)
NFC maintainers should really take a look at this.
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