[dpdk-dev] [PATCH] lib/librte_timer:fix corruption with reset

[Sarosh Arif]

If the user tries to reset/stop some other timer in it's callback
function, which is also about to expire, using 
rte_timer_reset_sync/rte_timer_stop_sync the application goes into
an infinite loop. This happens because 
rte_timer_reset_sync/rte_timer_stop_sync loop until the timer 
resets/stops and there is check inside timer_set_config_state which
prevents a running timer from being reset/stopped by not it's own 
timer_cb. Therefore timer_set_config_state returns -1 due to which 
rte_timer_reset returns -1 and rte_timer_reset_sync goes into an 
infinite loop. 

The soloution to this problem is to return -1 from 
rte_timer_reset_sync/rte_timer_stop_sync in case the user tries to 
reset/stop some other timer in it's callback function.

Bugzilla ID: 491
Fixes: 20d159f20543 ("timer: fix corruption with reset")
Cc: h.mikit...@gmail.com
Signed-off-by: Sarosh Arif <sarosh.a...@emumba.com>
---
 lib/librte_timer/rte_timer.c | 25 +++++++++++++++++++++++--
 lib/librte_timer/rte_timer.h |  4 ++--
 2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/lib/librte_timer/rte_timer.c b/lib/librte_timer/rte_timer.c
index 6d19ce469..ed48bcbfd 100644
--- a/lib/librte_timer/rte_timer.c
+++ b/lib/librte_timer/rte_timer.c
@@ -576,14 +576,24 @@ rte_timer_alt_reset(uint32_t timer_data_id, struct 
rte_timer *tim,
 }
 
 /* loop until rte_timer_reset() succeed */
-void
+int
 rte_timer_reset_sync(struct rte_timer *tim, uint64_t ticks,
                     enum rte_timer_type type, unsigned tim_lcore,
                     rte_timer_cb_t fct, void *arg)
 {
+       struct rte_timer_data *timer_data;
+       TIMER_DATA_VALID_GET_OR_ERR_RET(default_data_id, timer_data, -EINVAL);
+
+       if (tim->status.state == RTE_TIMER_RUNNING &&   \
+       (tim->status.owner != (uint16_t)tim_lcore ||    \
+       tim != timer_data->priv_timer[tim_lcore].running_tim))
+               return -1;
+
        while (rte_timer_reset(tim, ticks, type, tim_lcore,
                               fct, arg) != 0)
                rte_pause();
+
+       return 0;
 }
 
 static int
@@ -642,11 +652,22 @@ rte_timer_alt_stop(uint32_t timer_data_id, struct 
rte_timer *tim)
 }
 
 /* loop until rte_timer_stop() succeed */
-void
+int
 rte_timer_stop_sync(struct rte_timer *tim)
 {
+       struct rte_timer_data *timer_data;
+       TIMER_DATA_VALID_GET_OR_ERR_RET(default_data_id, timer_data, -EINVAL);
+       unsigned int lcore_id = rte_lcore_id();
+
+       if (tim->status.state == RTE_TIMER_RUNNING &&   \
+       (tim->status.owner != (uint16_t)lcore_id ||     \
+       tim != timer_data->priv_timer[lcore_id].running_tim))
+               return -1;
+
        while (rte_timer_stop(tim) != 0)
                rte_pause();
+
+       return 0;
 }
 
 /* Test the PENDING status of the timer handle tim */
diff --git a/lib/librte_timer/rte_timer.h b/lib/librte_timer/rte_timer.h
index c6b3d450d..392ca423d 100644
--- a/lib/librte_timer/rte_timer.h
+++ b/lib/librte_timer/rte_timer.h
@@ -275,7 +275,7 @@ int rte_timer_reset(struct rte_timer *tim, uint64_t ticks,
  * @param arg
  *   The user argument of the callback function.
  */
-void
+int
 rte_timer_reset_sync(struct rte_timer *tim, uint64_t ticks,
                     enum rte_timer_type type, unsigned tim_lcore,
                     rte_timer_cb_t fct, void *arg);
@@ -314,7 +314,7 @@ int rte_timer_stop(struct rte_timer *tim);
  * @param tim
  *   The timer handle.
  */
-void rte_timer_stop_sync(struct rte_timer *tim);
+int rte_timer_stop_sync(struct rte_timer *tim);
 
 /**
  * Test if a timer is pending.
-- 
2.17.1