* David OShea ([email protected]) wrote: > Hi all, > > I have an application that works as expected when I run it from a shell, but > when I start it as a daemon from an init script, it outputs a message like > this every 4 or 5 seconds: > > libust[15229/15231]: Error: Error opening shm (in get_wait_shm() at > lttng-ust-comm.c:480) > > I did a little debugging to try and work out what was going on. I didn't > actually end up seeing get_wait_shm() being called, but I noticed that > ust_listener_thread() was entering the block of code containing: > > DBG("Info: sessiond not accepting connections to %s apps socket", > sock_info->name); > > It appeared that this was because the sock_path was empty. From looking at > sock_info, the wait_shm_path is also empty as shown below, as confirmed in > the error message above where "Error opening shm" was meant to be followed by > the path that was being opened but instead is just followed by two spaces: > > (gdb) p * (struct sock_info *) arg > $7 = {name = 0x2b2721bd8b48 "local", ust_listener = 1110300992, root_handle = > -1, constructor_sem_posted = 1, allowed = 1, global = 0, sock_path = '\000' > <repeats 4095 times>, socket = -1, wait_shm_path = '\000' <repeats 4095 > times>, wait_shm_mmap = 0x0} > > setup_local_apps() appears to not fill in the sock_path and wait_shm_path if > the HOME environment variable is not set, which is the case for my daemon. > Looking back, I can see that this message appeared during my application's > startup: > > libust[15229/15229]: Error: Error setting up to local apps (in > lttng_ust_init() at lttng-ust-comm.c:895) > > which is the indicator that setup_local_apps() failed. > > I assume that lttng-ust is attempting to connect to a per-user session > daemon, but can't since HOME is not set. In my case, the application is > running as root and connecting to the global session daemon, so I don't mind > that it can't connect to a per-user session daemon. It would be nice if I > didn't have to get all of those error messages, although I can certainly > ignore them for now and could consider working around them by just making > sure HOME is set to something :) > > I'm using lttng-ust-2.0.5 which I have patched with commit 009745db "Cache > the procname per-thread rather than per-process to take into account that > prctl() can be used to set thread names."
Thanks for reporting! Can you try with stable-2.0 branch or master branch head ? Here are the commits: stable-2.0: commit e699eda9762d3cf3b0c40329eb3b6ce0947789dc Author: Mathieu Desnoyers <[email protected]> Date: Mon Oct 29 21:39:42 2012 -0400 Cleanup: don't spawn per-user thread if HOME is not set Reported-by: David OShea <[email protected]> Signed-off-by: Mathieu Desnoyers <[email protected]> master: commit 9ec6895c5633ed93c5acdf1e5b06f075fbd709d3 Author: Mathieu Desnoyers <[email protected]> Date: Mon Oct 29 21:39:42 2012 -0400 Cleanup: don't spawn per-user thread if HOME is not set Reported-by: David OShea <[email protected]> Signed-off-by: Mathieu Desnoyers <[email protected]> Thanks, Mathieu > > Thanks in advance, > David > > ---------------------------------------------------------------------- > The information contained in this transmission may be confidential. Any > disclosure, copying, or further distribution of confidential information is > not permitted unless such privilege is explicitly granted in writing by > Quantum. Quantum reserves the right to have electronic communications, > including email and attachments, sent across its networks filtered through > anti virus and spam software programs and retain such messages in order to > comply with applicable data security and retention requirements. Quantum is > not responsible for the proper and complete transmission of the substance of > this communication or for any delay in its receipt. > > _______________________________________________ > lttng-dev mailing list > [email protected] > http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev -- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com _______________________________________________ lttng-dev mailing list [email protected] http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
