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kgdbts: fix hw_access_break_test

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The test for access watchpoints (hw_access_break_test) was broken
(always failed) because the compiler optimized out the write to the
static helper variable (hw_break_val2), as it is never read anywhere.
This resulted in the target variable (hw_break_val) not being accessed
and thus the breakpoint not being triggered.

Remove the helper variable (hw_break_val2), and use READ_ONCE to force
reading the target variable (hw_break_val).

Signed-off-by: Florian Rommel <mail@florommel.de>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20240812085459.291741-1-mail@florommel.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Florian Rommel 2024-08-12 10:54:59 +02:00 committed by Greg Kroah-Hartman
parent 9ca12e50a4
commit 4a017c0163
1 changed files with 2 additions and 2 deletions
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4
drivers/misc/kgdbts.c
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@ -95,6 +95,7 @@
#include <linux/kallsyms.h>
#include <asm/sections.h>
#include <asm/rwonce.h>
#define v1printk(a...) do { \
if (verbose) \
@ -126,7 +127,6 @@ static int final_ack;
static int force_hwbrks;
static int hwbreaks_ok;
static int hw_break_val;
static int hw_break_val2;
static int cont_instead_of_sstep;
static unsigned long cont_thread_id;
static unsigned long sstep_thread_id;
@ -284,7 +284,7 @@ static void hw_rem_access_break(char *arg)
static void hw_break_val_access(void)
{
hw_break_val2 = hw_break_val;
READ_ONCE(hw_break_val);
}
static void hw_break_val_write(void)