[PATCH] timer: mask unnecessary set of flags in do_init_timer

From: Qianli Zhao
Date: Thu Aug 06 2020 - 22:29:47 EST


From: Qianli Zhao <zhaoqianli@xxxxxxxxxx>

do_init_timer can specify flags of timer_list,
but this function does not expect to specify the CPU or idx.
If user invoking do_init_timer and specify CPU,
The result may not what we expected.

E.g:
do_init_timer invoked in core2,and specify flags 0x1
final result flags is 0x3.If the specified CPU number
exceeds the actual number,more serious problems will happen

Signed-off-by: Qianli Zhao <zhaoqianli@xxxxxxxxxx>
---
kernel/time/timer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 026ac01..17e3737 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -789,7 +789,7 @@ static void do_init_timer(struct timer_list *timer,
{
timer->entry.pprev = NULL;
timer->function = func;
- timer->flags = flags | raw_smp_processor_id();
+ timer->flags = (flags & ~TIMER_BASEMASK & ~TIMER_ARRAYMASK) | raw_smp_processor_id();
lockdep_init_map(&timer->lockdep_map, name, key, 0);
}

--
2.7.4