[lttng-dev] Odd behaviour of lttng 2.0 kernel event listing

[David Goulet]

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That's very interesting.

Quick fix, let see if it works:

diff --git a/src/common/sessiond-comm/sessiond-comm.c
b/src/common/sessiond-comm/sessiond-comm.c
index 03e8931..106041f 100644
- --- a/src/common/sessiond-comm/sessiond-comm.c
+++ b/src/common/sessiond-comm/sessiond-comm.c
@@ -257,7 +257,7 @@ ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
        msg.msg_iov = iov;
        msg.msg_iovlen = 1;

- -       ret = recvmsg(sock, &msg, 0);
+       ret = recvmsg(sock, &msg, MSG_WAITALL);
        if (ret < 0) {
                perror("recvmsg");
        }

Thanks!

Getting there :)

David

On 12-01-23 05:37 PM, Thibault, Daniel wrote:
>    I've narrowed it down to lttng-ctl.ask_sessiond(): the first recv_data_sessiond() call expects 16 bytes (sizeof(llm)) and gets 16 bytes.  llm.data_size holds the payload size (in bytes), which is what the second recv_data_sessiond() call expects...But it receives only 15 984 bytes of the expected 41 208.  The problem is that ask_sessiond() then reports the asked-for size as what it returned, without checking if they match.  15 984 bytes is 19 event records and 78% of a 20th record, which is exactly what we see in the session log (events 21 onward are blank).
> 
> Daniel U. Thibault
> R & D pour la défense Canada - Valcartier (RDDC Valcartier) / Defence R&D Canada - Valcartier (DRDC Valcartier)
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> 
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