[PATCH] time: Fix casting issue in tk_set_xtime and tk_xtime_add

[PATCH] time: Fix casting issue in tk_set_xtime and tk_xtime_add

[John Stultz]

Fix missing casts that can cause boot problems on 32bit systems,
most easily observed with Xen systems. This issue was introduced
w/ 1e75fa8be9fb61e1af46b5b3b176347a4c958ca1.

Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
 kernel/time/timekeeping.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index f045cc5..cf364db 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -108,13 +108,13 @@ static struct timespec tk_xtime(struct timekeeper *tk)
 static void tk_set_xtime(struct timekeeper *tk, const struct timespec *ts)
 {
 	tk->xtime_sec = ts->tv_sec;
-	tk->xtime_nsec = ts->tv_nsec << tk->shift;
+	tk->xtime_nsec = (u64)ts->tv_nsec << tk->shift;
 }
 
 static void tk_xtime_add(struct timekeeper *tk, const struct timespec *ts)
 {
 	tk->xtime_sec += ts->tv_sec;
-	tk->xtime_nsec += ts->tv_nsec << tk->shift;
+	tk->xtime_nsec += (u64)ts->tv_nsec << tk->shift;
 }
 
 /**
-- 
1.7.9.5

Re: [PATCH] time: Fix casting issue in tk_set_xtime and tk_xtime_add

[Prarit Bhargava]

On 07/23/2012 04:22 PM, John Stultz wrote:
> Fix missing casts that can cause boot problems on 32bit systems,
> most easily observed with Xen systems. This issue was introduced
> w/ 1e75fa8be9fb61e1af46b5b3b176347a4c958ca1.
> 
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Prarit Bhargava <prarit@redhat.com>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> Signed-off-by: John Stultz <john.stultz@linaro.org>

Acked-by: Prarit Bhargava <prarit@redhat.com>

P.

[tip:timers/urgent] time: Fix casting issue in tk_set_xtime and tk_xtime_add

[tip-bot for John Stultz]

Commit-ID:  b44d50dcacea0d485ca2ff9140f8cc28ee22f28d
Gitweb:     http://git.kernel.org/tip/b44d50dcacea0d485ca2ff9140f8cc28ee22f28d
Author:     John Stultz <john.stultz@linaro.org>
AuthorDate: Mon, 23 Jul 2012 16:22:37 -0400
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Tue, 24 Jul 2012 16:48:45 +0200

time: Fix casting issue in tk_set_xtime and tk_xtime_add

commit 1e75fa8b (time: Condense timekeeper.xtime into xtime_sec)
introduced helper functions which apply a timespec to the core
internal timekeeper data. The internal storage type is u64. The
timespec tv_nsec value must be shifted before set or added to the
internal value. tv_nsec is a long, which is 32bit on a 32bit system,
so without casting tv_nsec to u64 we lose the bits which are shifted
over the 32bit boundary.

Add the proper typecasts.

Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Acked-by: Prarit Bhargava <prarit@redhat.com>
Link: http://lkml.kernel.org/r/1343074957-16541-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/time/timekeeping.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 5980e90..8f2aba1 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -108,13 +108,13 @@ static struct timespec tk_xtime(struct timekeeper *tk)
 static void tk_set_xtime(struct timekeeper *tk, const struct timespec *ts)
 {
 	tk->xtime_sec = ts->tv_sec;
-	tk->xtime_nsec = ts->tv_nsec << tk->shift;
+	tk->xtime_nsec = (u64)ts->tv_nsec << tk->shift;
 }
 
 static void tk_xtime_add(struct timekeeper *tk, const struct timespec *ts)
 {
 	tk->xtime_sec += ts->tv_sec;
-	tk->xtime_nsec += ts->tv_nsec << tk->shift;
+	tk->xtime_nsec += (u64)ts->tv_nsec << tk->shift;
 }
 
 /**

[PATCH] time: Fix casting issue in timekeeping_forward_now

[Andreas Schwab]

arch_gettimeoffset returns a u32 value which when shifted by tk->shift can
overflow.  Cast it to u64 first.

Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
---
Found this by inspection, I don't know if any existing users of
ARCH_USES_GETTIMEOFFSET are affected.  In other words, this is untested,
but looks pretty obvious.

Can tk->shift be bigger than 30?  If so then the shifts in
update_wall_time need to be adjusted as well.

Andreas.

---
 kernel/time/timekeeping.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index e16af19..8776d66 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -276,7 +276,7 @@ static void timekeeping_forward_now(struct timekeeper *tk)
 	tk->xtime_nsec += cycle_delta * tk->mult;
 
 	/* If arch requires, add in gettimeoffset() */
-	tk->xtime_nsec += arch_gettimeoffset() << tk->shift;
+	tk->xtime_nsec += (u64)arch_gettimeoffset() << tk->shift;
 
 	tk_normalize_xtime(tk);
 
-- 
1.7.11.5

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."