D28889: Avoid crash in KWin::DrmOutput::updateCursor

meven added a comment.


    Thread 1 has target name 'kwin_wayland'
    Thread 1 has target id 'Thread 0x7f7ef2cdc3c0 (LWP 9387)'
    Thread 2 has target name 'QDBusConnection'
    Thread 2 has target id 'Thread 0x7f7ed8408700 (LWP 9388)'
    Thread 3 has target name 'QThread'
    Thread 3 has target id 'Thread 0x7f7ed75a3700 (LWP 9389)'
    Thread 4 has target name 'libinput-connec'
    Thread 4 has target id 'Thread 0x7f7ed6da2700 (LWP 9390)'
    Thread 5 has target name 'kwin_wa:disk$0'
    Thread 5 has target id 'Thread 0x7f7ec61c3700 (LWP 9391)'
    Thread 6 has target name 'Thread (pooled)'
    Thread 6 has target id 'Thread 0x7f7ebffff700 (LWP 9393)'
    (gdb) thread apply all bt
    
    Thread 6 (Thread 0x7f7ebffff700 (LWP 9393)):
    #0  0x00007f7ef110e384 in __libc_read (fd=23, buf=0x7f7ebfffeba7, nbytes=1) at ../sysdeps/unix/sysv/linux/read.c:27
    #1  0x00007f7eefb93e55 in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
    #2  0x00007f7eefbc343e in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
    #3  0x00007f7eefb41964 in QAbstractFileEngine::readLine(char*, long long) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
    #4  0x00007f7eefb94450 in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
    #5  0x00007f7eefb5a14f in QFileDevice::readLineData(char*, long long) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
    #6  0x00007f7eefb62ecb in QIODevice::readLine(char*, long long) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
    #7  0x00007f7eefb6332d in QIODevice::readLine(long long) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
    #8  0x0000564c62b353b9 in  ()
    #9  0x0000564c62b36346 in  ()
    #10 0x00007f7eefa4af42 in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
    #11 0x00007f7eefa477ec in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
    #12 0x00007f7ef11046db in start_thread (arg=0x7f7ebffff700) at pthread_create.c:463
    #13 0x00007f7eef11488f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95
    
    Thread 5 (Thread 0x7f7ec61c3700 (LWP 9391)):
    #0  0x00007f7ef110a9f3 in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x564c64a97408) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
    #1  0x00007f7ef110a9f3 in __pthread_cond_wait_common (abstime=0x0, mutex=0x564c64a973b8, cond=0x564c64a973e0) at pthread_cond_wait.c:502
    #2  0x00007f7ef110a9f3 in __pthread_cond_wait (cond=0x564c64a973e0, mutex=0x564c64a973b8) at pthread_cond_wait.c:655
    #3  0x00007f7ec763decb in  () at /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
    #4  0x00007f7ec763dac7 in  () at /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
    #5  0x00007f7ef11046db in start_thread (arg=0x7f7ec61c3700) at pthread_create.c:463
    #6  0x00007f7eef11488f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95
    
    Thread 4 (Thread 0x7f7ed6da2700 (LWP 9390)):
    #0  0x00007f7eef107bf9 in __GI___poll (fds=0x7f7ecc0029e0, nfds=2, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
    #1  0x00007f7ee62a65c9 in  () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
    #2  0x00007f7ee62a66dc in g_main_context_iteration () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
    #3  0x00007f7eefc960db in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
    #4  0x00007f7eefc3563a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
    #5  0x00007f7eefa46317 in QThread::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
    #6  0x00007f7eefa477ec in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
    #7  0x00007f7ef11046db in start_thread (arg=0x7f7ed6da2700) at pthread_create.c:463
    #8  0x00007f7eef11488f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95
    
    Thread 3 (Thread 0x7f7ed75a3700 (LWP 9389)):
    #0  0x00007f7eef107bf9 in __GI___poll (fds=0x7f7ec8002de0, nfds=2, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
    #1  0x00007f7ee62a65c9 in  () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
    #2  0x00007f7ee62a66dc in g_main_context_iteration () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
    #3  0x00007f7eefc960bc in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
    #4  0x00007f7eefc3563a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
    #5  0x00007f7eefa46317 in QThread::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
    #6  0x00007f7eefa477ec in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
    #7  0x00007f7ef11046db in start_thread (arg=0x7f7ed75a3700) at pthread_create.c:463
    #8  0x00007f7eef11488f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95
    
    Thread 2 (Thread 0x7f7ed8408700 (LWP 9388)):
    #0  0x00007f7eef107bf9 in __GI___poll (fds=0x7f7ed00053d0, nfds=2, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
    #1  0x00007f7ee62a65c9 in  () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
    #2  0x00007f7ee62a66dc in g_main_context_iteration () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
    #3  0x00007f7eefc960bc in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
    #4  0x00007f7eefc3563a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
    #5  0x00007f7eefa46317 in QThread::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
    #6  0x00007f7ef0e83555 in  () at /usr/lib/x86_64-linux-gnu/libQt5DBus.so.5
    #7  0x00007f7eefa477ec in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
    #8  0x00007f7ef11046db in start_thread (arg=0x7f7ed8408700) at pthread_create.c:463
    #9  0x00007f7eef11488f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95
    
    Thread 1 (Thread 0x7f7ef2cdc3c0 (LWP 9387)):
    #0  0x00007f7eef107cf6 in __GI_ppoll (fds=0x564c64bc8678, nfds=6, timeout=<optimized out>, sigmask=0x0) at ../sysdeps/unix/sysv/linux/ppoll.c:39
    #1  0x00007f7eefc91df1 in qt_safe_poll(pollfd*, unsigned long, timespec const*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
    #2  0x00007f7eefc935b2 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
    #3  0x00007f7edb63dc1d in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/KWinQpaPlugin.so
    #4  0x0000564c62b34882 in  ()
    #5  0x0000564c62b34969 in  ()
    #6  0x0000564c62b21a57 in  ()
    #7  0x0000564c62b1f828 in  ()
    #8  0x00007f7eef014b97 in __libc_start_main (main=
        0x564c62b1e5a0, argc=4, argv=0x7ffdbec40ce8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffdbec40cd8) at ../csu/libc-start.c:310
    #9  0x0000564c62b2084a in _start ()

REPOSITORY
  R108 KWin

REVISION DETAIL
  https://phabricator.kde.org/D28889

To: meven, #kwin, zzag, davidedmundson
Cc: kwin, Orage, cacarry, LeGast00n, The-Feren-OS-Dev, cblack, jraleigh, zachus, fbampaloukas, mkulinski, ragreen, jackyalcine, iodelay, crozbo, bwowk, ZrenBot, ngraham, alexeymin, himcesjf, lesliezhai, ali-mohamed, hardening, romangg, jensreuterberg, abetts, sebas, apol, ahiemstra, mart