Messages in this thread | | | From | Arnd Bergmann <> | Date | Mon, 27 Mar 2017 16:53:09 +0200 | Subject | Re: [PATCH] trace: Make trace_hwlat timestamp y2038 safe |
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On Mon, Mar 27, 2017 at 4:28 PM, Steven Rostedt <rostedt@goodmis.org> wrote: > On Mon, 27 Mar 2017 11:55:52 +0200 > Arnd Bergmann <arnd@arndb.de> wrote: > >> On Mon, Mar 27, 2017 at 11:25 AM, kbuild test robot <lkp@intel.com> wrote: >> > Hi Deepa, >> > >> > [auto build test WARNING on tip/perf/core] >> > [also build test WARNING on v4.11-rc4 next-20170327] >> > [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] >> > >> > url: https://github.com/0day-ci/linux/commits/Deepa-Dinamani/trace-Make-trace_hwlat-timestamp-y2038-safe/20170327-150010 >> > config: x86_64-randconfig-n0-03271517 (attached as .config) >> > compiler: gcc-4.8 (Debian 4.8.4-1) 4.8.4 >> > reproduce: >> > # save the attached .config to linux build tree >> > make ARCH=x86_64 >> > >> > All warnings (new ones prefixed by >>): >> > >> > kernel/trace/trace_output.c: In function 'trace_hwlat_print': >> >>> kernel/trace/trace_output.c:1168:5: warning: format '%lld' expects argument of type 'long long int', but argument 6 has type '__kernel_time_t' [-Wformat=] >> > field->timestamp.tv_nsec); >> >> This happens on 64-bit architectures because 'struct timespec64' is defined to >> be equal to 'struct timespec', which has a 'long' tv_sec rather than >> 'long long'. >> >> A cast to 's64' is probably the best workaround. >> >> > kernel/trace/trace_output.c: In function 'trace_hwlat_raw': >> > kernel/trace/trace_output.c:1202:5: warning: format '%lld' expects argument of type 'long long int', but argument 5 has type '__kernel_time_t' [-Wformat=] >> > field->seqnum); >> >> Same here. >> > > Actually, I believe that "%zd" will work. It's made to work with size_t > which is long long on 32 and long on 64.
size_t is always 'long', not 'long long'. We have %pad for dma_addr_t which may be 'long' or 'long long', but it is configuration dependent which one it is on 32-bit.
We could probably introduce a %pts format string for timespec64 and have that pretty-printed.
Arnd
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