The patch titled
hangcheck-timer: fix x86_32 bugs
has been added to the -mm tree. Its filename is
hangcheck-timer-fix-x86_32-bugs.patch
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------------------------------------------------------
Subject: hangcheck-timer: fix x86_32 bugs
From: Yury Polyanskiy <ypolyans@xxxxxxxxxxxxx>
drivers/char/hangcheck-timer.c is doubly broken. First, the following
line overflows unsigned long:
# define TIMER_FREQ (HZ*loops_per_jiffy)
Second, and more importantly, loops_per_jiffy has little to do with the
con= version from the the time scale of get_cycles() (aka rdtsc) to the
time scale of jiffies.
The attached patch resolves both of the problems.
Cc: Joel Becker <joel.becker@xxxxxxxxxx>
Cc: john stultz <johnstul@xxxxxxxxxx>
Cc: Jan Glauber <jan.glauber@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/char/hangcheck-timer.c | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)
diff -puN drivers/char/hangcheck-timer.c~hangcheck-timer-fix-x86_32-bugs drivers/char/hangcheck-timer.c
--- a/drivers/char/hangcheck-timer.c~hangcheck-timer-fix-x86_32-bugs
+++ a/drivers/char/hangcheck-timer.c
@@ -49,8 +49,9 @@
#include <asm/uaccess.h>
#include <linux/sysrq.h>
#include <linux/timer.h>
+#include <linux/time.h>
-#define VERSION_STR "0.9.0"
+#define VERSION_STR "0.9.1"
#define DEFAULT_IOFENCE_MARGIN 60 /* Default fudge factor, in seconds */
#define DEFAULT_IOFENCE_TICK 180 /* Default timer timeout, in seconds */
@@ -119,10 +120,8 @@ __setup("hcheck_dump_tasks", hangcheck_p
#if defined(CONFIG_S390)
# define HAVE_MONOTONIC
# define TIMER_FREQ 1000000000ULL
-#elif defined(CONFIG_IA64)
-# define TIMER_FREQ ((unsigned long long)local_cpu_data->itc_freq)
#else
-# define TIMER_FREQ (HZ*loops_per_jiffy)
+# define TIMER_FREQ 1000000000ULL
#endif
#ifdef HAVE_MONOTONIC
@@ -130,7 +129,9 @@ extern unsigned long long monotonic_cloc
#else
static inline unsigned long long monotonic_clock(void)
{
- return get_cycles();
+ struct timespec ts;
+ getrawmonotonic(&ts);
+ return timespec_to_ns(&ts);
}
#endif /* HAVE_MONOTONIC */
@@ -168,6 +169,13 @@ static void hangcheck_fire(unsigned long
printk(KERN_CRIT "Hangcheck: hangcheck value past margin!\n");
}
}
+#if 0
+ /*
+ * Enable to investigate delays in detail
+ */
+ printk("Hangcheck: called %Ld ns since last time (%Ld ns overshoot)\n",
+ tsc_diff, tsc_diff - hangcheck_tick*TIMER_FREQ);
+#endif
mod_timer(&hangcheck_ticktock, jiffies + (hangcheck_tick*HZ));
hangcheck_tsc = monotonic_clock();
}
@@ -180,7 +188,7 @@ static int __init hangcheck_init(void)
#if defined (HAVE_MONOTONIC)
printk("Hangcheck: Using monotonic_clock().\n");
#else
- printk("Hangcheck: Using get_cycles().\n");
+ printk("Hangcheck: Using getrawmonotonic().\n");
#endif /* HAVE_MONOTONIC */
hangcheck_tsc_margin =
(unsigned long long)(hangcheck_margin + hangcheck_tick);
_
Patches currently in -mm which might be from ypolyans@xxxxxxxxxxxxx are
hangcheck-timer-fix-x86_32-bugs.patch
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