[PATCH 2/6] x86/hw-breakpoints: Actually flush thread breakpoints in flush_thread().

From: Frederic Weisbecker
Date: Sun Nov 01 2009 - 16:10:09 EST

From: Paul Mundt <lethal@xxxxxxxxxxxx>

flush_thread() tries to do a TIF_DEBUG check before calling in to
flush_thread_hw_breakpoint() (which subsequently clears the thread flag),
but for some reason, the x86 code is manually clearing TIF_DEBUG
immediately before the test, so this path will never be taken.

This kills off the erroneous clear_tsk_thread_flag() and lets
flush_thread_hw_breakpoint() actually get invoked.

Presumably folks were getting lucky with testing and the
free_thread_info() -> free_thread_xstate() path was taking care of the
flush there.

Signed-off-by: Paul Mundt <lethal@xxxxxxxxxxxx>
Acked-by: "K.Prasad" <prasad@xxxxxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
LKML-Reference: <20091005102306.GA7889@xxxxxxxxxxxx>
Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
arch/x86/kernel/process.c | 2 --
1 files changed, 0 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 2275ce5..cf8ee00 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -107,8 +107,6 @@ void flush_thread(void)

- clear_tsk_thread_flag(tsk, TIF_DEBUG);
if (unlikely(test_tsk_thread_flag(tsk, TIF_DEBUG)))
memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));

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