Login | Register For Free | Help
Search for: (Advanced)

Mailing List Archive: Linux: Kernel

[PATCH] time: Fix casting issue in timekeeping_forward_now

 

 

Linux kernel RSS feed   Index | Next | Previous | View Threaded


schwab at linux-m68k

Aug 19, 2012, 1:09 PM

Post #1 of 1 (88 views)
Permalink
[PATCH] time: Fix casting issue in timekeeping_forward_now

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 [at] linux-m68k>
---
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 [at] linux-m68k
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo [at] vger
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

Linux kernel RSS feed   Index | Next | Previous | View Threaded
 
 


Interested in having your list archived? Contact Gossamer Threads
 
  Web Applications & Managed Hosting Powered by Gossamer Threads Inc.