189637 - Are Exit Routines called too early?

Status: RESOLVED INCOMPLETE

(Core :: XPCOM, defect)

Description

[timeless]

==12167== 8 bytes in 1 blocks are still reachable in loss record 2 of 20
==12167==    at 0x40046E1B: __builtin_new (vg_clientfuncs.c:125)
==12167==    by 0x40384CDD: NS_RegisterXPCOMExitRoutine
(/mnt/ibm/mozhack/mozilla/xpcom/build/nsXPComInit.cpp:633)
==12167==    by 0x4046785B: SetupGlobalMemory(void)
(/mnt/ibm/mozhack/mozilla/xpcom/glue/nsMemory.cpp:59)
==12167==    by 0x40467A22: nsMemory::Clone(void const *, unsigned int)
(/mnt/ibm/mozhack/mozilla/xpcom/glue/nsMemory.cpp:120)
==12167==    by 0x41A44E4A: nsXPCComponents::GetClassName(char **)
(../../../../dist/include/xpconnect/xpc_map_end.h:50)
==12167==    by 0x41A813B1: XPCNativeScriptableInfo::Construct(XPCCallContext &,
XPCNativeScriptableCreateInfo const *)
(/mnt/ibm/mozhack/mozilla/js/src/xpconnect/src/xpcwrappednativejsops.cpp:1151)
==12167==    by 0x41A725DC: XPCWrappedNative::Init(XPCCallContext &, JSObject *,
XPCNativeScriptableCreateInfo const *)
(/mnt/ibm/mozhack/mozilla/js/src/xpconnect/src/xpcwrappednative.cpp:700)
==12167==    by 0x41A70FA2: XPCWrappedNative::GetNewOrUsed(XPCCallContext &,
nsISupports *, XPCWrappedNativeScope *, XPCNativeInterface *, XPCWrappedNative
**) (/mnt/ibm/mozhack/mozilla/js/src/xpconnect/src/xpcwrappednative.cpp:373)
==12167==    by 0x41A45698:
nsXPCComponents::AttachNewComponentsObject(XPCCallContext &,
XPCWrappedNativeScope *, JSObject *)
(/mnt/ibm/mozhack/mozilla/js/src/xpconnect/src/xpccomponents.cpp:1742)
==12167==    by 0x41A32123: nsXPConnect::InitClasses(JSContext *, JSObject *)
(/mnt/ibm/mozhack/mozilla/js/src/xpconnect/src/nsXPConnect.cpp:438)
==12167==    by 0x41A632F4: XPCJSContextStack::GetSafeJSContext(JSContext **)
(/mnt/ibm/mozhack/mozilla/js/src/xpconnect/src/xpcthreadcontext.cpp:152)
==12167==    by 0x41A39C4E: XPCCallContext::XPCCallContext(XPCContext::LangType,
JSContext *, JSObject *, JSObject *, long, unsigned int, long *, long *)
(/mnt/ibm/mozhack/mozilla/js/src/xpconnect/src/xpccallcontext.cpp:87)
==12167==    by 0x41A3126B: nsXPConnect::~nsXPConnect(void)
(/mnt/ibm/mozhack/mozilla/js/src/xpconnect/src/nsXPConnect.cpp:113)
==12167==    by 0x41A30DCF: nsXPConnect::Release(void)
(/mnt/ibm/mozhack/mozilla/js/src/xpconnect/src/nsXPConnect.cpp:41)
==12167==    by 0x41A3160D: nsXPConnect::ReleaseXPConnectSingleton(void)
(/mnt/ibm/mozhack/mozilla/js/src/xpconnect/src/nsXPConnect.cpp:231)
==12167==    by 0x41A60BE0: xpcModuleDtor(nsIModule *)
(/mnt/ibm/mozhack/mozilla/js/src/xpconnect/src/xpcmodule.cpp:105)
==12167==    by 0x40466464: nsGenericModule::Shutdown(void)
(/mnt/ibm/mozhack/mozilla/xpcom/glue/nsGenericFactory.cpp:363)
==12167==    by 0x40465E76: nsGenericModule::~nsGenericModule(void)
(/mnt/ibm/mozhack/mozilla/xpcom/glue/nsGenericFactory.cpp:240)
==12167==    by 0x40465FDA: nsGenericModule::Release(void)
(/mnt/ibm/mozhack/mozilla/xpcom/glue/nsGenericFactory.cpp:248)
==12167==    by 0x4040F055: nsDll::Shutdown(void)
(/mnt/ibm/mozhack/mozilla/xpcom/components/xcDll.cpp:383)

Comment 1

[timeless]

Attachment: release gExitRoutines when it's empty

Comment 2

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

Why isn't CallExitRoutines deleting it?

Comment 3

[timeless]

Comment on attachment 111953 [details] [diff] [review]
release gExitRoutines when it's empty

i dunno.
what i do know is that valgrind lists it.
stepping through xpcshell shows that CallExitRoutines is called and does delete
and null gExitRoutines.

valgrind doesn't like it when gdb pokes its victim with a breakpoint (report
sent), so i'm not sure what's going on or how to find out. CallExitRoutines
only has one entry so I should be able to figure this out...

the valgrind params i'm using are:
/usr/local/bin/valgrind --error-limit=no --num-callers=20 -v --leak-check=yes
--show-reachable=yes

Comment 4

[timeless]

ok, i think i figured out the problem. it looks like the exit routines are
called too early.

I have two valgrind stacks showing the leak from:
NS_RegisterXPCOMExitRoutine
(/mnt/ibm/mozhack/mozilla/xpcom/build/nsXPComInit.cpp:633)
SetupGlobalMemory(void) (/mnt/ibm/mozhack/mozilla/xpcom/glue/nsMemory.cpp:59)
nsMemory::Free(void *) (/mnt/ibm/mozhack/mozilla/xpcom/glue/nsMemory.cpp:102)
Which is probably bad :)

Comment 5

[timeless]

Attachment: smoking gun

Comment 6

[timeless]

Attachment: without 'fix'

RegFactory is an app based on a compiling version of
mozilla/xpcom/tests/RegFactory.cpp i'll commit that later.

Logs are created using the following commands:

/usr/local/bin/valgrind --error-limit=no --num-callers=20 -v --leak-check=yes
--show-reachable=yes ./RegFactory ./components/nsSample.js 2>
RegFactory.valgrind2

perl -pi -e 's/^.?==\d+==//;s/^.?--\d+--//;s/ record \d+ of \d+$/ record.../;s/
  (?:at|by) 0x[\dA-F]{8}://' RegFactory.valgrind2

Comment 7

[timeless]

Attachment: with 'fix'

Comment 8

[timeless]

Attachment: 'fix'

Comment 9

[Benjamin Smedberg]

Exit routines were removed.