/me has to retract comment #13, it is indeed the app printing the message. Camera app has 2 threads printing it
sudo strace -f -e write -p `pidof camera-app` 2>&1 | grep ust [pid 14107] write(2, "libust[14085/14107]: Error: Erro"..., 114 <unfinished ...> [pid 14106] write(2, "libust[14085/14106]: Error: Erro"..., 108) = 108 and looking at the threads involved: (gdb) i thre Id Target Id Frame 20 Thread 0xb2f67410 (LWP 14097) "RPC Thread" 0xb64ca4e2 in poll () at ../sysdeps/unix/syscall-template.S:81 19 Thread 0xb23e1410 (LWP 14099) "arch_worker" 0xb46ab840 in ?? () 18 Thread 0xb2442b40 (LWP 14100) "camera-app" __libc_do_syscall () at ../sysdeps/unix/sysv/linux/arm/libc-do-syscall.S:47 17 Thread 0xb19ff410 (LWP 14101) "SWD-GPU Job" __libc_do_syscall () at ../sysdeps/unix/sysv/linux/arm/libc-do-syscall.S:46 16 Thread 0xb11ff410 (LWP 14102) "SWD-Frame" __libc_do_syscall () at ../sysdeps/unix/sysv/linux/arm/libc-do-syscall.S:46 15 Thread 0xb07bb410 (LWP 14104) "QQmlThread" 0xb64ca4e2 in poll () at ../sysdeps/unix/syscall-template.S:81 14 Thread 0xae6b2410 (LWP 14106) "QQmlThread" 0xb64ae4e2 in nanosleep () at ../sysdeps/unix/syscall-template.S:81 13 Thread 0xadeb2410 (LWP 14107) "QQmlThread" 0xb64ae4e2 in nanosleep () at ../sysdeps/unix/syscall-template.S:81 12 Thread 0xad0ff410 (LWP 14110) "gdbus" 0xb64ca4e2 in poll () at ../sysdeps/unix/syscall-template.S:81 11 Thread 0xab97a410 (LWP 14112) "camera-app" __libc_do_syscall () at ../sysdeps/unix/sysv/linux/arm/libc-do-syscall.S:46 10 Thread 0xa9faa410 (LWP 14117) "QQuickPixmapRea" 0xb64ca4e2 in poll () at ../sysdeps/unix/syscall-template.S:81 9 Thread 0xa9223410 (LWP 14118) "Input dispatch" 0xb64ca4e2 in poll () at ../sysdeps/unix/syscall-template.S:81 8 Thread 0xa83ff410 (LWP 14124) "camera-app" 0xb64d1132 in epoll_wait () at ../sysdeps/unix/syscall-template.S:81 7 Thread 0xa7bff410 (LWP 14126) "QSGRenderThread" __libc_do_syscall () at ../sysdeps/unix/sysv/linux/arm/libc-do-syscall.S:46 6 Thread 0xa73ff410 (LWP 14127) "Swap Worker" __libc_do_syscall () at ../sysdeps/unix/sysv/linux/arm/libc-do-syscall.S:46 5 Thread 0xa63ff410 (LWP 14128) "camera-app" 0xb46ac9f4 in ?? () 4 Thread 0xa5bff410 (LWP 14140) "Binder_1" 0xb46ab840 in ?? () 3 Thread 0xa53ff410 (LWP 14141) "Binder_2" 0xb46ab840 in ?? () 2 Thread 0xa4bff410 (LWP 14172) "Binder_3" 0xb46ab840 in ?? () * 1 Thread 0xb6f32000 (LWP 14085) "camera-app" __libc_do_syscall () at ../sysdeps/unix/sysv/linux/arm/libc-do-syscall.S:46 (gdb) t 14 [Switching to thread 14 (Thread 0xae6b2410 (LWP 14106))] #0 0xb64ae4e2 in nanosleep () at ../sysdeps/unix/syscall-template.S:81 81 ../sysdeps/unix/syscall-template.S: No such file or directory. (gdb) bt #0 0xffffffff in nanosleep () at ../sysdeps/unix/syscall-template.S:81 #1 0xffffffff in __sleep (seconds=0) at ../sysdeps/unix/sysv/linux/sleep.c:138 #2 0xffffffff in () at /usr/lib/arm-linux-gnueabihf/liblttng-ust.so.0 (gdb) t 13 [Switching to thread 13 (Thread 0xadeb2410 (LWP 14107))] #0 0xb64ae4e2 in nanosleep () at ../sysdeps/unix/syscall-template.S:81 81 in ../sysdeps/unix/syscall-template.S (gdb) bt #0 0xffffffff in nanosleep () at ../sysdeps/unix/syscall-template.S:81 #1 0xffffffff in __sleep (seconds=0) at ../sysdeps/unix/sysv/linux/sleep.c:138 #2 0xffffffff in () at /usr/lib/arm-linux-gnueabihf/liblttng-ust.so.0 (gdb) Still dunno what exact project is responsible -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to webbrowser-app in Ubuntu. https://bugs.launchpad.net/bugs/1404302 Title: liblttng-ust0 Error opening shm /lttng-ust-wait-5 Status in Client Developer Experience: Confirmed Status in platform-api: New Status in qtmir package in Ubuntu: Invalid Status in webbrowser-app package in Ubuntu: Confirmed Bug description: Confined apps don't have access to this and continuously produce this error message in stderr: libust[31283/31285]: Error: Error opening shm /lttng-ust-wait-5 (in get_wait_shm() at lttng-ust-comm.c:958) This is printed to the application's log about once every other second and makes it hard to read the application's own debug output. For a better app developer experience this message should be silenced. To manage notifications about this bug go to: https://bugs.launchpad.net/canonical-developer-experience/+bug/1404302/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
