This bug was filed from the Socorro interface and is report bp-f1b89c71-b5ec-416a-82c8-ac70e2110821 . ============================================================= Seen while looking at crash reports. https://crash-stats.mozilla.com/report/list?signature=__addAltHandler2 links to the crashes which happen across versions. High concentration of 10.5.x crashes. Two comments mention "The browser had been acting extremely slow for several minutes for the crash" Frame Module Signature [Expand] Source 0 CoreFoundation __addAltHandler2 1 CoreFoundation _CFDoExceptionOperation 2 Foundation _NSAddExceptionHandlerForLock 3 AppKit _NSAppKitLock 4 AppKit -[NSApplication _findWindowUsingCache:] 5 AppKit -[NSEvent window] 6 AppKit -[NSEvent _cgsEventRecord] 7 AppKit -[NSEvent _eventRefInternal] 8 AppKit -[NSEvent _postAtStart:] 9 XUL nsAppShell::ProcessGeckoEvents widget/src/cocoa/nsAppShell.mm:439 10 CoreFoundation __CFRunLoopDoSources0 11 CoreFoundation __CFRunLoopRun 12 CoreFoundation CFRunLoopRunSpecific 13 CoreFoundation CFRunLoopRunInMode 14 HIToolbox RunCurrentEventLoopInMode 15 HIToolbox ReceiveNextEventCommon 16 HIToolbox BlockUntilNextEventMatchingListInMode 17 AppKit _DPSNextEvent 18 AppKit -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] 19 XUL nsAppShell::ProcessNextNativeEvent widget/src/cocoa/nsAppShell.mm:675 20 XUL nsBaseAppShell::OnProcessNextEvent widget/src/xpwidgets/nsBaseAppShell.cpp:171 21 XUL nsAppShell::OnProcessNextEvent widget/src/cocoa/nsAppShell.mm:856 22 XUL nsThread::ProcessNextEvent xpcom/threads/nsThread.cpp:582 23 XUL NS_ProcessPendingEvents_P obj-firefox/i386/xpcom/build/nsThreadUtils.cpp:195 24 XUL nsBaseAppShell::NativeEventCallback widget/src/xpwidgets/nsBaseAppShell.cpp:130 25 XUL nsAppShell::ProcessGeckoEvents widget/src/cocoa/nsAppShell.mm:422 26 CoreFoundation __CFRunLoopDoSources0 27 CoreFoundation __CFRunLoopRun 28 CoreFoundation CFRunLoopRunSpecific 29 CoreFoundation CFRunLoopRunInMode 30 HIToolbox RunCurrentEventLoopInMode 31 HIToolbox ReceiveNextEventCommon 32 HIToolbox BlockUntilNextEventMatchingListInMode 33 AppKit _DPSNextEvent 34 AppKit -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] 35 AppKit -[NSApplication run] 36 XUL nsAppShell::Run widget/src/cocoa/nsAppShell.mm:769 37 XUL nsAppStartup::Run toolkit/components/startup/nsAppStartup.cpp:222 38 XUL XRE_main toolkit/xre/nsAppRunner.cpp:3686 39 firefox-bin main browser/app/nsBrowserApp.cpp:158 40 firefox-bin firefox-bin@0xa05 41
It's #3 top crasher in 7.0.1 on Mac OS X. It happens almost only on Mac OS X 10.5 with Flash Player: 98% (53/54) vs. 27% (579/2128) FlashPlayer-10.4-10.5 2% (1/54) vs. 0% (7/2128) 48F84FE6AB8341F943264EE657D564330 4% (2/54) vs. 1% (15/2128) 618100E683D0F650E7AB834638DB5F6A0 20% (11/54) vs. 6% (123/2128) 9E0D5FDCE905F569CBE364E85AC98BFC0 4% (2/54) vs. 3% (71/2128) 9E952D5BE0C7A400FF8D0D280BE6E3990 37% (20/54) vs. 10% (212/2128) AB20F8CBD0050FDF33413B314A53F9150 4% (2/54) vs. 1% (18/2128) CCAF6CF191CA2C8EB8ED19375014F2130 4% (2/54) vs. 0% (4/2128) CDB00B650C699A1DBD9350A6EF4A36CA0 7% (4/54) vs. 2% (38/2128) ED71BBFA041EF60C49672DDA0CC6569C0 17% (9/54) vs. 3% (63/2128) FFCFA8DE6C45E84EB674EC324644884A0
This is still a valid top crash. Sits at #2 spot for all mac crashes on 8.0.1.
Adding Steven to the bug. This shows up in Firefox 9b4 but in pretty small volume - 38 crashes. Based on the correlation, perhaps something is happening when the browser is interacting with Flash on 10.5?
fyi, Flash version support for OSX 10.5 stopped at 10.3. the latest version is 10,3,183,10.
Stacks with this signature have been around for a long time, across all versions of Firefox and of OS X. But it's only in the last few months that we've started to see so many of them on OS X 10.5.8. (I'll try to get a timeline for this in a later comment). These crashes occur deep in system code. But if I'm interpreting Breakpad's raw dump format correctly, they're all the result of the failure of a call to malloc() (on OS X 10.5.8) or calloc() (on OS X 10.6.8) inside the __addAltHandler2() function. (More, too, on this in a later comment.) This is extremely puzzling. It's very unlikely that ordinary memory pressure (i.e. running out of memory) is responsible for these failures. Otherwise they'd be just one part of a whole cluster of "out of memory" errors, which I'm pretty sure we haven't seen. If we'd enabled jemalloc on OS X 10.5 in FF 8.0.1, that'd be my first suspect. But we haven't. Which leads me to wonder if this is some kind of OS bug. And also to wonder if Flash has some part in it, perhaps by (somehow) intercepting calls to malloc() and calloc(). (Once again, more on this in a later comment.)
In the raw dumps of this bug's Breakpad crash stacks on OS X 10.5.8, the top line of the crash stack is represented as follows: 0|0|CoreFoundation|__addAltHandler2|||0xf6 I take this to mean that these crashes (all of them NULL dereferences) take place at offset 0xf6 (decimal 246) from the beginning of the __addAltHandler2() function. From the assembly code at that offset, you can see that a call to malloc() that returns NULL will cause a NULL derefence at that offset: 0x934b13f8 <__addAltHandler2+232>: movl $0x9c,(%esp) 0x934b13ff <__addAltHandler2+239>: call 0xa0a46588 <dyld_stub_malloc> 0x934b1404 <__addAltHandler2+244>: mov %eax,%edx 0x934b1406 <__addAltHandler2+246>: movl $0xc,(%eax) The few examples of this crash on OS X 10.6.8 happen at a different offset from the beginning of __addAltHander2(): 0|0|CoreFoundation|__addAltHandler2|||0x12a Hexadecimal 0x12a translates into decimal 298. But __addAltHandler2() is slightly longer on OS X 10.6.8, and its assembly code shows that these crashes take place as the result of a call to calloc() that returns NULL: 0x03c5ee54 <__addAltHandler2+276>: movl $0x9c,0x4(%esp) 0x03c5ee5c <__addAltHandler2+284>: movl $0x1,(%esp) 0x03c5ee63 <__addAltHandler2+291>: call 0x3d29758 <dyld_stub_calloc> 0x03c5ee68 <__addAltHandler2+296>: mov %eax,%ebx 0x03c5ee6a <__addAltHandler2+298>: movl $0xc,(%ebx)
On both OS X 10.5.8 and 10.6.8, the current version of the OS-specific Flash Player "PlugIn" has the following string: [mem] gc[%d] %s allocator: %d%% efficiency %d bytes (%d kb) in use out of %d bytes (%d kb) This seems to imply that Flash has a way of measuring allocator "efficiency", and some kind of garbage collection.
Another thing to note (though many of you will already have realized it): Even on OS X 10.6.8 and 10.7.X, these crashes only happen in 32-bit mode.
Yet another thing to note: The allocations that are failing are very small -- 0x9c bytes (156 decimal).
There were 543 crashes at __addAltHandler2 in all FF versions in the last week. The number slowly falls as you go further back. But the most dramatic change that I can find is between the week ending 2011/08/28 (324) and the one ending 2011/08/21 (206). This is just after FF 6.0 was released. I don't know how it corresponds to the Flash release schedule.
(In reply to Steven Michaud from comment #10) > This is just after FF 6.0 was released. I don't know how it > corresponds to the Flash release schedule. Flash 10.3 was released in May 2011 and Flash 11.0 in October 2011 (see http://en.wikipedia.org/wiki/Adobe_Flash_Player#Release_history). There was a security fix in Flash 10.3.183.5 released on August 12th (see http://www.adobe.com/support/security/bulletins/apsb11-21.html).
(Following up comment #5) > It's very unlikely that ordinary memory pressure (i.e. running out > of memory) is responsible for these failures. Otherwise they'd be > just one part of a whole cluster of "out of memory" errors, which > I'm pretty sure we haven't seen. And if these were ordinary out-of-memory symptoms, you'd think high uptimes would be heavily overrepresented in the crash stats. But as best I can tell (by eyeballing them) the uptimes are pretty evenly distributed. Anyone know what the "uptime" unit is? Is it seconds?
(In reply to Steven Michaud from comment #12) > Anyone know what the "uptime" unit is? Is it seconds? Yes. It's currently #9 top crasher in 10.0 and #16 in 11.0b1 on Mac OS X.
This still sitting in the top 5 for Mac crashes on release. At #5 on 10.0.2 with 300 crashes a week.
99% of crashes happen on Mac OS X 10.5.
Let's close it as WFM now that Mac OS X 10.5 is no longer supported in Firefox 17.