I've also been getting random tab crashes since a few days ago=
, mesa git (and I
upgraded to the latest git master HEAD at around the time the issues started
happening), but my backtrace is difference.

(gdb) bt
#0  0x00007f7d1f0c8087 in drm_get_pci_id_for_fd (fd=3Dfd@entry=3D36,
vendor_id=3Dvendor_id@entry=3D0x7ffd32efaaa0, chip_id=3Dchip_id@ent=
ry=3D0x7ffd32efaaa4)
at ../mesa-9999/src/loader/loader.c:281
#1  0x00007f7d1f0c86e9 in loader_get_pci_id_for_fd (fd=3Dfd@entry=3D36,
vendor_id=3Dvendor_id@entry=3D0x7ffd32efaaa0, chip_id=3Dchip_id@ent=
ry=3D0x7ffd32efaaa4)
at ../mesa-9999/src/loader/loader.c:306
#2  0x00007f7d1f0c7e35 in pipe_loader_drm_probe_fd
(dev=3Ddev@entry=3D0x7ffd32efaad0, fd=3Dfd@entry=3D36) at
../mesa-9999/src/gallium/auxiliary/pipe-loader/pipe_loader_drm.c:180
#3  0x00007f7d1f0c7f5f in pipe_loader_drm_probe (devs=3Ddevs@entry=3D0x=
0,
ndev=3Dndev@entry=3D0) at
../mesa-9999/src/gallium/auxiliary/pipe-loader/pipe_loader_drm.c:237
#4  0x00007f7d1f0c750f in pipe_loader_probe (devs=3Ddevs@entry=3D0x0,
ndev=3Dndev@entry=3D0) at
../mesa-9999/src/gallium/auxiliary/pipe-loader/pipe_loader.c:65
#5  0x00007f7d1f0c19f8 in clover::platform::platform() () at
../mesa-9999/src/gallium/state_trackers/clover/core/platform.cpp:28
#6  0x00007f7d1f096d66 in __static_initialization_and_destruction_0
(__initialize_p=3D1, __priority=3D65535) at
../mesa-9999/src/gallium/state_trackers/clover/api/platform.cpp:145
#7  _GLOBAL__sub_I_platform.cpp(void) () at
../mesa-9999/src/gallium/state_trackers/clover/api/platform.cpp:145
#8  0x00007f7d5496954a in call_init (l=3D<optimized out>, argc=3Dargc=
@entry=3D17,
argv=3Dargv@entry=3D0x7ffd32efcbd8, env=3Denv@entry=3D0x7f7d52f1540=
0) at dl-init.c:72
#9  0x00007f7d54969654 in call_init (env=3D0x7f7d52f15400, argv=3D0x7ffd32e=
fcbd8,
argc=3D17, l=3D<optimized out>) at dl-init.c:30
#10 _dl_init (main_map=3Dmain_map@entry=3D0x7f7d37925000, argc=3D17,
argv=3D0x7ffd32efcbd8, env=3D0x7f7d52f15400) at dl-init.c:119
#11 0x00007f7d5496d8f3 in dl_open_worker (a=3Da@entry=3D0x7ffd32efb0d0)=
 at
dl-open.c:511
#12 0x00007f7d53a6694f in __GI__dl_catch_exception
(exception=3Dexception@entry=3D0x7ffd32efb0b0, operate=3Doperate@en=
try=3D0x7f7d5496d550
<dl_open_worker>, args=3Dargs@entry=3D0x7ffd32efb0d0) at dl-error=
-skeleton.c:196
#13 0x00007f7d5496d187 in _dl_open (file=3D0x7f7d47ca6e89 "libavcodec.=
so.58",
mode=3D-2147483646, caller_dlopen=3D0x7f7d536ecc73 <PR_LoadLibraryWithFl=
ags+275>,
nsid=3D<optimized out>, argc=3D17, argv=3D0x7ffd32efcbd8,=20
    env=3D0x7f7d52f15400) at dl-open.c:594
#14 0x00007f7d54311fba in dlopen_doit (a=3Da@entry=3D0x7ffd32efb320) at=
 dlopen.c:66
#15 0x00007f7d53a6694f in __GI__dl_catch_exception
(exception=3Dexception@entry=3D0x7ffd32efb2b0, operate=3Doperate@en=
try=3D0x7f7d54311f50
<dlopen_doit>, args=3Dargs@entry=3D0x7ffd32efb320) at dl-error-sk=
eleton.c:196
#16 0x00007f7d53a669ef in __GI__dl_catch_error
(objname=3Dobjname@entry=3D0x7f7d52f140b0,
errstring=3Derrstring@entry=3D0x7f7d52f140b8,
mallocedp=3Dmallocedp@entry=3D0x7f7d52f140a8,=20
    operate=3Doperate@entry=3D0x7f7d54311f50 <dlopen_doit>,
args=3Dargs@entry=3D0x7ffd32efb320) at dl-error-skeleton.c:215
#17 0x00007f7d5431283d in _dlerror_run (operate=3Doperate@entry=3D0x7f7=
d54311f50
<dlopen_doit>, args=3Dargs@entry=3D0x7ffd32efb320) at dlerror.c:1=
62
#18 0x00007f7d54312066 in __dlopen (file=3Dfile@entry=3D0x7f7d47ca6e89
"libavcodec.so.58", mode=3D<optimized out>) at dlopen.c:87
#19 0x00007f7d536ecc73 in pr_LoadLibraryByPathname (flags=3D10,
name=3D0x7f7d47ca6e89 "libavcodec.so.58") at
/usr/src/debug/dev-libs/nspr-4.19/nspr-4.19/nspr/pr/src/linking/prlink.c:803
#20 PR_LoadLibraryWithFlags (libSpec=3D..., flags=3Dflags@entry=3D10) at
/usr/src/debug/dev-libs/nspr-4.19/nspr-4.19/nspr/pr/src/linking/prlink.c:418
#21 0x00007f7d45c2d746 in mozilla::FFmpegRuntimeLinker::Init () at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/dom/media/platforms/=
ffmpeg/FFmpegRuntimeLinker.cpp:64
#22 0x00007f7d45c2d9df in mozilla::FFmpegRuntimeLinker::Init () at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/dom/media/platforms/=
ffmpeg/FFmpegRuntimeLinker.cpp:51
#23 0x00007f7d45c037b7 in mozilla::PDMFactoryImpl::PDMFactoryImpl
(this=3D0x7f7d2dab89f8) at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/dom/media/platforms/=
PDMFactory.cpp:76
#24 mozilla::PDMFactory::EnsureInit (this=3D<optimized out>) at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/dom/media/platforms/=
PDMFactory.cpp:188
#25 0x00007f7d45c04510 in mozilla::PDMFactory::PDMFactory (this=3D0x7f7d2db=
e7c70)
at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/dom/media/platforms/=
PDMFactory.cpp:168
#26 0x00007f7d45cebc91 in
mozilla::MP4Decoder::IsSupportedType(mozilla::MediaContainerType const&,
mozilla::DecoderDoctorDiagnostics*) [clone .part.299] ()
    at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/ff/dist/include/mozi=
lla/mozalloc.h:156
#27 0x00007f7d45a47b48 in mozilla::DecoderTraits::IsSupportedType (aType=3D=
...)
at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/dom/media/DecoderTra=
its.cpp:289
#28 0x00007f7d45a7e936 in mozilla::ChannelMediaDecoder::Create (aInit=3D...,
aDiagnostics=3DaDiagnostics@entry=3D0x7ffd32efb660)
    at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/dom/media/ChannelMed=
iaDecoder.cpp:213
#29 0x00007f7d459edf7b in
mozilla::dom::HTMLMediaElement::InitializeDecoderForChannel
(this=3Dthis@entry=3D0x7f7d2ed61000, aChannel=3D<optimized out>, =
aListener=3D<optimized
out>)
    at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/dom/html/HTMLMediaEl=
ement.cpp:4891
#30 0x00007f7d459ee44b in
mozilla::dom::HTMLMediaElement::MediaLoadListener::OnStartRequest
(this=3D0x7f7d377b6ce0, aRequest=3D0x7f7d37939868, aContext=3D0x0)
    at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/ff/dist/include/nsCO=
MPtr.h:795
#31 0x00007f7d444fcf23 in mozilla::net::HttpChannelChild::DoOnStartRequest
(this=3Dthis@entry=3D0x7f7d37939800, aRequest=3DaRequest@entry=3D0x=
7f7d37939868,
aContext=3D0x0)
    at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/netwerk/protocol/htt=
p/HttpChannelChild.cpp:744
#32 0x00007f7d444fd4b2 in
mozilla::net::HttpChannelChild::OnStartRequest(nsresult const&,
mozilla::net::nsHttpResponseHead const&, bool const&,
mozilla::net::nsHttpHeaderArray const&,
mozilla::net::ParentLoadInfoForwarderArgs const&, bool const&, bool=
 const&,
unsigned long const&, int const&, unsigned int const&, nsTStrin=
g<char> const&,
nsTString<char> const&, mozilla::net::NetAddr const&, mozilla=
::net::NetAddr
const&, unsigned int const&, nsTString<char> const&, long=
 const&,
mozilla::Maybe<mozilla::dom::ServiceWorkerDescriptor> const&, boo=
l const&) ()
    at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/ff/dist/include/nsCO=
MPtr.h:1109
#33 0x00007f7d444fd86d in mozilla::net::StartRequestEvent::Run
(this=3D0x7f7d37c5e3f0) at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/netwerk/protocol/htt=
p/HttpChannelChild.cpp:467
#34 0x00007f7d444fa42d in mozilla::net::ChannelEventQueue::RunOrEnqueue
(aAssertionWhenNotQueued=3Dfalse, aCallback=3D<optimized out>, this=
=3D0x7f7d2dc12a00)
    at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/ff/dist/include/mozi=
lla/UniquePtr.h:326
#35 mozilla::net::HttpChannelChild::RecvOnStartRequest(nsresult const&,
mozilla::net::nsHttpResponseHead const&, bool const&,
mozilla::net::nsHttpHeaderArray const&,
mozilla::net::ParentLoadInfoForwarderArgs const&, bool const&, bool=
 const&,
unsigned long const&, int const&, unsigned int const&, nsTStrin=
g<char> const&,
nsTString<char> const&, mozilla::net::NetAddr const&, mozilla=
::net::NetAddr
const&, short const&, unsigned int const&, nsTString<char>=
; const&, long const&,
mozilla::dom::OptionalIPCServiceWorkerDescriptor const&, bool const&=
;) ()
    at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/netwerk/protocol/htt=
p/HttpChannelChild.cpp:537
#36 0x00007f7d44728c2f in mozilla::net::PHttpChannelChild::OnMessageReceived
(this=3D0x7f7d37939800, msg__=3D...) at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/ff/ipc/ipdl/PHttpCha=
nnelChild.cpp:701
#37 0x00007f7d446c8338 in mozilla::dom::PContentChild::OnMessageReceived
(this=3D0x7f7d52f71020, msg__=3D...) at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/ff/ipc/ipdl/PContent=
Child.cpp:5316
#38 0x00007f7d44639e7f in
mozilla::ipc::MessageChannel::DispatchAsyncMessage(IPC::Message const&)=
 () at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/ipc/glue/MessageChan=
nel.cpp:2142
#39 0x00007f7d44640c99 in
mozilla::ipc::MessageChannel::DispatchMessage(IPC::Message&&) () at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/ipc/glue/MessageChan=
nel.cpp:2072
#40 0x00007f7d44642b2f in
mozilla::ipc::MessageChannel::RunMessage(mozilla::ipc::MessageChannel::Mess=
ageTask&)
() at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/ipc/glue/MessageChan=
nel.cpp:1918
#41 0x00007f7d44642cda in mozilla::ipc::MessageChannel::MessageTask::Run() =
()
at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/ipc/glue/MessageChan=
nel.cpp:1951
#42 0x00007f7d4431731c in mozilla::SchedulerGroup::Runnable::Run() () at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/ff/dist/include/nsCO=
MPtr.h:805
#43 0x00007f7d4431a1fe in nsThread::ProcessNextEvent(bool, bool*) () at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/xpcom/threads/nsThre=
ad.cpp:1090
#44 0x00007f7d44323438 in NS_ProcessNextEvent (aThread=3D<optimized out&=
gt;,
aThread@entry=3D0x7f7d52fcbc80, aMayWait=3DaMayWait@entry=3Dfalse)
    at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/xpcom/threads/nsThre=
adUtils.cpp:519
#45 0x00007f7d4463309a in
mozilla::ipc::MessagePump::Run(base::MessagePump::Delegate*) () at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/ipc/glue/MessagePump=
.cpp:97
#46 0x00007f7d4460f774 in MessageLoop::RunInternal (this=3D<optimized ou=
t>) at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/ff/dist/include/mozi=
lla/RefPtr.h:315
#47 MessageLoop::RunHandler (this=3D<optimized out>) at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/ipc/chromium/src/bas=
e/message_loop.cc:319
#48 MessageLoop::Run (this=3D<optimized out>) at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/ipc/chromium/src/bas=
e/message_loop.cc:299
#49 0x00007f7d460e2b98 in nsBaseAppShell::Run (this=3D0x7f7d3bab8580) at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/widget/nsBaseAppShel=
l.cpp:157
#50 0x00007f7d46e56477 in XRE_RunAppShell () at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/toolkit/xre/nsEmbedF=
unctions.cpp:896
#51 0x00007f7d4460f774 in MessageLoop::RunInternal (this=3D0x7ffd32efc890) =
at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/ff/dist/include/mozi=
lla/RefPtr.h:315
#52 MessageLoop::RunHandler (this=3D0x7ffd32efc890) at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/ipc/chromium/src/bas=
e/message_loop.cc:319
#53 MessageLoop::Run (this=3Dthis@entry=3D0x7ffd32efc890) at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/ipc/chromium/src/bas=
e/message_loop.cc:299
#54 0x00007f7d46e56971 in XRE_InitChildProcess(int, char**, XREChildData
const*) () at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/toolkit/xre/nsEmbedF=
unctions.cpp:722
#55 0x00005579a32fc226 in content_process_main (bootstrap=3D0x7f7d52f30630,
argc=3D16, argv=3D0x7ffd32efcbd8) at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/ipc/contentproc/plug=
in-container.cpp:50
#56 0x00005579a32fbd60 in main (argc=3D17, argv=3D0x7ffd32efcbd8,
envp=3D0x7ffd32efcc68) at
/usr/src/debug/www-client/firefox-61.0-r1/firefox-61.0/ff/dist/include/mozi=
lla/UniquePtr.h:326

I'm not sure if the issues are connected, but I can try downgrading to mesa
stable and seeing if the issues still happen. If they don't, I'll attempt
bisecting.