| Message ID | 1449187944-11730-1-git-send-email-sasha.levin@oracle.com |
|---|---|
| State | Superseded |
| Headers | show |
[if your patch is applied to the wrong git tree, please drop us a note to help improving the system]
Hi Sasha,
[auto build test ERROR on abelloni/rtc-next]
[also build test ERROR on v4.4-rc3 next-20151202]
url: https://github.com/0day-ci/linux/commits/Sasha-Levin/rtc-fix-overflow-and-incorrect-calculation-in-rtc_time64_to_tm/20151204-081508
base: https://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux.git rtc-next
config: i386-tinyconfig (attached as .config)
reproduce:
# save the attached .config to linux build tree
make ARCH=i386
All errors (new ones prefixed by >>):
drivers/built-in.o: In function `rtc_time64_to_tm':
>> (.text+0x6795): undefined reference to `__moddi3'
drivers/built-in.o: In function `rtc_time64_to_tm':
>> (.text+0x67aa): undefined reference to `__divdi3'
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
[if your patch is applied to the wrong git tree, please drop us a note to help improving the system]
Hi Sasha,
[auto build test ERROR on abelloni/rtc-next]
[also build test ERROR on v4.4-rc3 next-20151202]
url: https://github.com/0day-ci/linux/commits/Sasha-Levin/rtc-fix-overflow-and-incorrect-calculation-in-rtc_time64_to_tm/20151204-081508
base: https://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux.git rtc-next
config: avr32-mimc200_defconfig (attached as .config)
reproduce:
wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=avr32
All errors (new ones prefixed by >>):
crypto/built-in.o: warning: input is not relaxable
virt/built-in.o: warning: input is not relaxable
drivers/built-in.o: In function `phy_device_create':
>> (.text+0x3c70c): undefined reference to `__avr32_smod64'
drivers/built-in.o: In function `phy_device_create':
(.text+0x3c710): undefined reference to `__avr32_sdiv64'
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
[if your patch is applied to the wrong git tree, please drop us a note to help improving the system]
Hi Sasha,
[auto build test ERROR on abelloni/rtc-next]
[also build test ERROR on v4.4-rc3 next-20151202]
url: https://github.com/0day-ci/linux/commits/Sasha-Levin/rtc-fix-overflow-and-incorrect-calculation-in-rtc_time64_to_tm/20151204-081508
base: https://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux.git rtc-next
config: arm-prima2_defconfig (attached as .config)
reproduce:
wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=arm
All errors (new ones prefixed by >>):
drivers/built-in.o: In function `rtc_time64_to_tm':
>> drivers/rtc/rtc-lib.c:64: undefined reference to `__aeabi_ldivmod'
drivers/rtc/rtc-lib.c:66: undefined reference to `__aeabi_ldivmod'
vim +64 drivers/rtc/rtc-lib.c
c58411e9 Alessandro Zummo 2006-03-27 58
c2c11ae4 pang.xunlei 2014-11-18 59 /* time must be positive */
c2c11ae4 pang.xunlei 2014-11-18 60 days = div_s64(time, 86400);
ee9fd0e8 Sasha Levin 2015-12-03 61 secs = time - days * 86400;
c58411e9 Alessandro Zummo 2006-03-27 62
c58411e9 Alessandro Zummo 2006-03-27 63 /* day of the week, 1970-01-01 was a Thursday */
c58411e9 Alessandro Zummo 2006-03-27 @64 tm->tm_wday = (days + 4) % 7;
c58411e9 Alessandro Zummo 2006-03-27 65
c58411e9 Alessandro Zummo 2006-03-27 66 year = 1970 + days / 365;
c58411e9 Alessandro Zummo 2006-03-27 67 days -= (year - 1970) * 365
:::::: The code at line 64 was first introduced by commit
:::::: c58411e95d7f5062dedd1a3064af4d359da1e633 [PATCH] RTC Subsystem: library functions
:::::: TO: Alessandro Zummo <a.zummo@towertech.it>
:::::: CC: Linus Torvalds <torvalds@g5.osdl.org>
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
On 03/12/2015 at 19:12:24 -0500, Sasha Levin wrote : > At some point after humans go extinct and robots cotrol the world, dividing > he time64_t by 86400 to extract the days will overflow a 32bit integer, > leading to incorrect conversion into rtc_time in rtc_time64_to_tm(). > And at that time, the robots won't care about 32bit platforms :) > Signed-off-by: Sasha Levin <sasha.levin@oracle.com> > --- > drivers/rtc/rtc-lib.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/rtc/rtc-lib.c b/drivers/rtc/rtc-lib.c > index e6bfb9c..459cd4d 100644 > --- a/drivers/rtc/rtc-lib.c > +++ b/drivers/rtc/rtc-lib.c > @@ -54,11 +54,11 @@ void rtc_time64_to_tm(time64_t time, struct rtc_time *tm) > { > unsigned int month, year; > unsigned long secs; > - int days; > + time64_t days; > > /* time must be positive */ > days = div_s64(time, 86400); > - secs = time - (unsigned int) days * 86400; > + secs = time - days * 86400; > > /* day of the week, 1970-01-01 was a Thursday */ > tm->tm_wday = (days + 4) % 7; > -- > 1.7.10.4 >
On 12/03/2015 08:55 PM, Alexandre Belloni wrote: > On 03/12/2015 at 19:12:24 -0500, Sasha Levin wrote : >> > At some point after humans go extinct and robots cotrol the world, dividing >> > he time64_t by 86400 to extract the days will overflow a 32bit integer, >> > leading to incorrect conversion into rtc_time in rtc_time64_to_tm(). >> > > And at that time, the robots won't care about 32bit platforms :) One can only hope... :) I'll resend. Thanks, Sasha
diff --git a/drivers/rtc/rtc-lib.c b/drivers/rtc/rtc-lib.c index e6bfb9c..459cd4d 100644 --- a/drivers/rtc/rtc-lib.c +++ b/drivers/rtc/rtc-lib.c @@ -54,11 +54,11 @@ void rtc_time64_to_tm(time64_t time, struct rtc_time *tm) { unsigned int month, year; unsigned long secs; - int days; + time64_t days; /* time must be positive */ days = div_s64(time, 86400); - secs = time - (unsigned int) days * 86400; + secs = time - days * 86400; /* day of the week, 1970-01-01 was a Thursday */ tm->tm_wday = (days + 4) % 7;
At some point after humans go extinct and robots cotrol the world, dividing he time64_t by 86400 to extract the days will overflow a 32bit integer, leading to incorrect conversion into rtc_time in rtc_time64_to_tm(). Signed-off-by: Sasha Levin <sasha.levin@oracle.com> --- drivers/rtc/rtc-lib.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)