When stressed by a load of clients starting at once: Failed to get PRIME fd from gbm bo

[Alan Griffiths]

I initially found this with miral-shell, but found similar behaviour with mir_demo_shell_minimal.

Start a shell, then start all the mir_demo_client_XXX apps. (For convenience see attached script.)

Then start closing apps one by one: At some point the server dies with a segfault.

With a bit of debugging I managed to catch the following error just before the segfault:

ERROR: /home/alan/display_server/mir/src/platforms/mesa/server/buffer_allocator.cpp(150): Throw in function virtual void {anonymous}::DMABufTextureBinder::ensure_egl_image()
Dynamic exception type: boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<std::system_error> >
std::exception::what: Failed to get PRIME fd from gbm bo: No such file or directory

[Alan Griffiths (alan-griffiths)]

A bit more investigation suggests this is only happening with mir-on-X11. Maybe something there is a bit racy.

[Daniel van Vugt (vanvugt)]

A crash under stress isn't low at least. Because once a number of people are using this code on a daily basis, even the most unlikely things will occur very regularly :)

[Alan Griffiths (alan-griffiths)]

OK, but I didn't consider a crash that only (so far) happens on Mir-on-X "Medium" as that isn't a setup likely in production.

[Mir CI Bot (mir-ci-bot)]

Fix committed into lp:mir at revision None, scheduled for release in mir, milestone 0.25.0

[Launchpad Janitor (janitor)]

This bug was fixed in the package mir - 0.25.0+17.04.20161203-0ubuntu1

---------------
mir (0.25.0+17.04.20161203-0ubuntu1) zesty; urgency=medium

  * New upstream release 0.25.0 (https://launchpad.net/mir/+milestone/0.25.0)
    - ABI summary:
      . mirclient ABI unchanged at 9
      . mirserver ABI bumped to 42
      . mircommon ABI bumped to 7
      . mirplatform ABI bumped to 14
      . mirprotobuf ABI unchanged at 3
      . mirplatformgraphics ABI bumped to 11
      . mirclientplatform ABI unchanged at 5
      . mirinputplatform ABI bumped to 6
      . mircore ABI added, at version 1
    - Enhancements:
      . Added pointer confinement support
      . Identify Raspberry Pi output types correctly
      . Added dead key and compose key support
      . Added gamma support for KMS hardware
      . Added yakkety and zesty gcc-6 support
      . Added surface passthrough support for fullscreen clients of nested
        servers
      . Introduced a new library `libmircore'
      . Began migrating from Protobuf to Cap'n Proto starting with events
      . Began support for VirtualBox (servers now start instead of crashing
        but full support for GL clients is still missing)
      . Began support for high precision frame timing, implemented for the
        KMS, Android and X11 backends so far
      . Added --display-report support for the X11 backend
      . Improved reliability of `mirvanity' latency test tool
      . Moved to using the CSS cursor naming scheme internally, although
        the old symbolic indentifiers remain unchanged and still work
      . Added refresh rate to MirSurfaceOutputEvent
      . Many improvements to automated test quality and coverage
      . Smoother desktop zoom using mir_proving_server (Super + two fingers)
    - Bugs fixed:
      . FTBFS On Zesty: invalid use of
        'struct native_handle' (LP: #1638774)
      . libmirclient-debug-extension-dev install debug/surface.h
        twice (LP: #1639153)
      . Mir crashes on virtual box drmModeCrtcSetGamma
        Function not implemented (LP: #1638220)
      . Flickering in mir_demo_client_multistream (LP: #1635273)
      . Camera apps (camera & vanity) never exit (LP: #1635010)
      . Clients cannot connect when MIR_SOCKET="" (LP: #1634508)
      . mirtest-dev packaging fails to sepcify boost depends (LP: #1633537)
      . cursor.h is unclear about mir_diagonal_resize_* (LP: #1626924)
      . Inconsistent underscores in cursor names (LP: #1632617)
      . [regression] Accidental libmircommon.so.6 break (LP: #1617865)
      . [regression] mir demo server fails to start with mx4 (LP: #1615703)
      . [regression] Trust prompt now shown when starting camera (LP: #1612256)
      . [regression] make abi-check fails to build (LP: #1626866)
      . Nested servers prevent overlays or fullscreen bypass (LP: #1262116)
      . Failed to get PRIME fd from gbm bo (LP: #1607812)
      . Mir-on-X is difficult to use on 1366x768 laptop (LP: #1590959)
      . Remove useless message 'Surface 0 DPI' in demos (LP: #1559831)
      . Mir fails to cross-build with newer sbuild (LP: #1628507)
      . Infinite loop in AbstractShell::focus_next_session (LP: #1625401)
      . Dest...