Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1323765

[PATCH] cputime: Fix timeval/timespec-->cputime conversion

Show all headers | View raw

The datatype __kernel_time_t is u32 on 32bit platform,
it will easily get overflow, so force u64 conversion.

Currently the following function will be affected:
1. setitimer()
2. timer_create/timer_settime()
3. sys_clock_nanosleep
And this will occur on MIPS32 and ARM32 with "Full dynticks CPU
time accounting" enabled, which is required for CONFIG_NO_HZ_FULL.

Signed-off-by: zengtao <prime.zeng@huawei.com>
---
 include/asm-generic/cputime_nsecs.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/include/asm-generic/cputime_nsecs.h b/include/asm-generic/cputime_nsecs.h
index 0419485..0f1c6f3 100644
--- a/include/asm-generic/cputime_nsecs.h
+++ b/include/asm-generic/cputime_nsecs.h
@@ -75,7 +75,7 @@ typedef u64 __nocast cputime64_t;
  */
 static inline cputime_t timespec_to_cputime(const struct timespec *val)
 {
-	u64 ret = val->tv_sec * NSEC_PER_SEC + val->tv_nsec;
+	u64 ret = (u64)val->tv_sec * NSEC_PER_SEC + val->tv_nsec;
 	return (__force cputime_t) ret;
 }
 static inline void cputime_to_timespec(const cputime_t ct, struct timespec *val)
@@ -91,7 +91,8 @@ static inline void cputime_to_timespec(const cputime_t ct, struct timespec *val)
  */
 static inline cputime_t timeval_to_cputime(const struct timeval *val)
 {
-	u64 ret = val->tv_sec * NSEC_PER_SEC + val->tv_usec * NSEC_PER_USEC;
+	u64 ret = (u64)val->tv_sec * NSEC_PER_SEC +
+			val->tv_usec * NSEC_PER_USEC;
 	return (__force cputime_t) ret;
 }
 static inline void cputime_to_timeval(const cputime_t ct, struct timeval *val)
-- 
1.9.1

Back to linux.kernel | Previous | Next — Next in thread | Find similar | Unroll thread

Thread

[PATCH] cputime: Fix timeval/timespec-->cputime conversion zengtao <prime.zeng@huawei.com> - 2016-02-02 04:40 +0100
  Re: [PATCH] cputime: Fix timeval/timespec-->cputime conversion Arnd Bergmann <arnd@arndb.de> - 2016-02-02 14:00 +0100
  [tip:timers/urgent] cputime: Prevent 32bit overflow in time[  val|spec]_to_cputime() tip-bot for zengtao <tipbot@zytor.com> - 2016-02-02 15:40 +0100

csiph-web