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debugobjects: Extend to assert that an object is initialized

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Calling del_timer_sync() on an uninitialized timer leads to a
never ending loop in lock_timer_base() that spins checking for a
non-NULL timer base. Add an assertion to debugobjects to catch
usage of uninitialized objects so that we can initialize timers
in the del_timer_sync() path before it calls lock_timer_base().

[ sboyd@codeaurora.org: Clarify commit message ]

Signed-off-by: Christine Chan <cschan@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/1320724108-20788-3-git-send-email-sboyd@codeaurora.org
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Christine Chan
2011-11-07 19:48:27 -08:00
committed by Thomas Gleixner
parent feac18dda2
commit b84d435cc2
3 changed files with 94 additions and 0 deletions
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50
Documentation/DocBook/debugobjects.tmpl
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@@ -96,6 +96,7 @@
<listitem><para>debug_object_deactivate</para></listitem>
<listitem><para>debug_object_destroy</para></listitem>
<listitem><para>debug_object_free</para></listitem>
<listitem><para>debug_object_assert_init</para></listitem>
</itemizedlist>
Each of these functions takes the address of the real object and
a pointer to the object type specific debug description
@@ -273,6 +274,26 @@
debug checks.
</para>
</sect1>
<sect1 id="debug_object_assert_init">
<title>debug_object_assert_init</title>
<para>
This function is called to assert that an object has been
initialized.
</para>
<para>
When the real object is not tracked by debugobjects, it calls
fixup_assert_init of the object type description structure
provided by the caller, with the hardcoded object state
ODEBUG_NOT_AVAILABLE. The fixup function can correct the problem
by calling debug_object_init and other specific initializing
functions.
</para>
<para>
When the real object is already tracked by debugobjects it is
ignored.
</para>
</sect1>
</chapter>
<chapter id="fixupfunctions">
<title>Fixup functions</title>
@@ -381,6 +402,35 @@
statistics.
</para>
</sect1>
<sect1 id="fixup_assert_init">
<title>fixup_assert_init</title>
<para>
This function is called from the debug code whenever a problem
in debug_object_assert_init is detected.
</para>
<para>
Called from debug_object_assert_init() with a hardcoded state
ODEBUG_STATE_NOTAVAILABLE when the object is not found in the
debug bucket.
</para>
<para>
The function returns 1 when the fixup was successful,
otherwise 0. The return value is used to update the
statistics.
</para>
<para>
Note, this function should make sure debug_object_init() is
called before returning.
</para>
<para>
The handling of statically initialized objects is a special
case. The fixup function should check if this is a legitimate
case of a statically initialized object or not. In this case only
debug_object_init() should be called to make the object known to
the tracker. Then the function should return 0 because this is not
a real fixup.
</para>
</sect1>
</chapter>
<chapter id="bugs">
<title>Known Bugs And Assumptions</title>