From: Lai Jiangshan Impact: fix time output bug in 32bits system ns2usecs() returns 'long', it's incorrect. (In i386) # cat trace ... -0 [000] 521.442100: _spin_lock <-tick_do_update_jiffies64 -0 [000] 521.442101: do_timer <-tick_do_update_jiffies64 -0 [000] 521.442102: update_wall_time <-do_timer -0 [000] 521.442102: update_xtime_cache <-update_wall_time .... (It always print the time less than 2200 seconds besides ...) Because 'long' is 32bits in i386. ( (1<<31) useconds is about 2200 seconds) # cat trace ... -0 [001] 4154502640.134759: rcu_bh_qsctr_inc <-__do_softirq -0 [001] 4154502640.134760: _local_bh_enable <-__do_softirq -0 [001] 4154502640.134761: idle_cpu <-irq_exit ... (very large value) Because 'long' is a signed type and it is 32bits in i386. Changed from V1: return 'unsigned long long' instead of 'cycle_t' Signed-off-by: Lai Jiangshan LKML-Reference: <49D05D10.4030009@cn.fujitsu.com> Reported-by: Li Zefan Acked-by: Frederic Weisbecker Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 3 +-- kernel/trace/trace.h | 2 +- kernel/trace/trace_output.c | 2 +- 3 files changed, 3 insertions(+), 4 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 67c6a21..222bbba 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -147,8 +147,7 @@ static int __init set_ftrace_dump_on_oops(char *str) } __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops); -long -ns2usecs(cycle_t nsec) +unsigned long long ns2usecs(cycle_t nsec) { nsec += 500; do_div(nsec, 1000); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index d7410bb..93991e6 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -594,7 +594,7 @@ extern int trace_selftest_startup_branch(struct tracer *trace, #endif /* CONFIG_FTRACE_STARTUP_TEST */ extern void *head_page(struct trace_array_cpu *data); -extern long ns2usecs(cycle_t nsec); +extern unsigned long long ns2usecs(cycle_t nsec); extern int trace_vbprintk(unsigned long ip, const char *fmt, va_list args); extern int diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index d72b9a6..64b54a5 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -423,7 +423,7 @@ int trace_print_lat_context(struct trace_iterator *iter) trace_find_cmdline(entry->pid, comm); - ret = trace_seq_printf(s, "%16s %5d %3d %d %08x %08lx [%08lx]" + ret = trace_seq_printf(s, "%16s %5d %3d %d %08x %08lx [%08llx]" " %ld.%03ldms (+%ld.%03ldms): ", comm, entry->pid, iter->cpu, entry->flags, entry->preempt_count, iter->idx, -- 1.6.2.1 -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/