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H A DMakefile3d0decc4 Fri Jul 11 08:09:15 CDT 2008 Ingo Molnar <mingo@elte.hu> x86: fix tsc unification buglet with ftrace and stackprotector

Yinghai Lu reported crashes on 64-bit x86:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
IP: [<ffffffff80253b17>] hrtick_start_fair+0x89/0x173
[...]

And with a long session of debugging and a lot of difficulty, tracked it down
to this commit:

--------------->
8fbbc4b45ce3e4c0eeb15004c79c72b6896a79c2 is first bad commit
commit 8fbbc4b45ce3e4c0eeb15004c79c72b6896a79c2
Author: Alok Kataria <akataria@vmware.com>
Date: Tue Jul 1 11:43:34 2008 -0700

x86: merge tsc_init and clocksource code
<--------------

The problem is that the TSC unification missed these Makefile rules
in arch/x86/kernel/Makefile:

# Do not profile debug and lowlevel utilities
CFLAGS_REMOVE_tsc_64.o = -pg
CFLAGS_REMOVE_tsc_32.o = -pg
...
CFLAGS_tsc_64.o := $(nostackp)
...

which rules make sure that various instrumentation and debugging
facilities are disabled for code that might end up in a VDSO - such as
the TSC code.

Reported-and-bisected-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Conflicts:

Signed-off-by: Ingo Molnar <mingo@elte.hu>
3d0decc4 Fri Jul 11 08:09:15 CDT 2008 Ingo Molnar <mingo@elte.hu> x86: fix tsc unification buglet with ftrace and stackprotector

Yinghai Lu reported crashes on 64-bit x86:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
IP: [<ffffffff80253b17>] hrtick_start_fair+0x89/0x173
[...]

And with a long session of debugging and a lot of difficulty, tracked it down
to this commit:

--------------->
8fbbc4b45ce3e4c0eeb15004c79c72b6896a79c2 is first bad commit
commit 8fbbc4b45ce3e4c0eeb15004c79c72b6896a79c2
Author: Alok Kataria <akataria@vmware.com>
Date: Tue Jul 1 11:43:34 2008 -0700

x86: merge tsc_init and clocksource code
<--------------

The problem is that the TSC unification missed these Makefile rules
in arch/x86/kernel/Makefile:

# Do not profile debug and lowlevel utilities
CFLAGS_REMOVE_tsc_64.o = -pg
CFLAGS_REMOVE_tsc_32.o = -pg
...
CFLAGS_tsc_64.o := $(nostackp)
...

which rules make sure that various instrumentation and debugging
facilities are disabled for code that might end up in a VDSO - such as
the TSC code.

Reported-and-bisected-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Conflicts:

Signed-off-by: Ingo Molnar <mingo@elte.hu>