tcf_tm_dump() reads fields that can be changed concurrently, and tcf_lastuse_update() might race against itself. Add READ_ONCE() and WRITE_ONCE() annotations. Fetch jiffies once in tcf_tm_dump(). Signed-off-by: Eric Dumazet --- include/net/act_api.h | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/include/net/act_api.h b/include/net/act_api.h index 04781c92b43d6ab9cc6c81a88d5c6fe8c282c590..2894cfff2da3fba2b6e197dea35134e2aad5af80 100644 --- a/include/net/act_api.h +++ b/include/net/act_api.h @@ -76,19 +76,24 @@ static inline void tcf_lastuse_update(struct tcf_t *tm) { unsigned long now = jiffies; - if (tm->lastuse != now) - tm->lastuse = now; - if (unlikely(!tm->firstuse)) - tm->firstuse = now; + if (READ_ONCE(tm->lastuse) != now) + WRITE_ONCE(tm->lastuse, now); + if (unlikely(!READ_ONCE(tm->firstuse))) + WRITE_ONCE(tm->firstuse, now); } static inline void tcf_tm_dump(struct tcf_t *dtm, const struct tcf_t *stm) { - dtm->install = jiffies_to_clock_t(jiffies - stm->install); - dtm->lastuse = jiffies_to_clock_t(jiffies - stm->lastuse); - dtm->firstuse = stm->firstuse ? - jiffies_to_clock_t(jiffies - stm->firstuse) : 0; - dtm->expires = jiffies_to_clock_t(stm->expires); + unsigned long firstuse, now = jiffies; + + dtm->install = jiffies_to_clock_t(now - READ_ONCE(stm->install)); + dtm->lastuse = jiffies_to_clock_t(now - READ_ONCE(stm->lastuse)); + + firstuse = READ_ONCE(stm->firstuse); + dtm->firstuse = firstuse ? + jiffies_to_clock_t(now - firstuse) : 0; + + dtm->expires = jiffies_to_clock_t(READ_ONCE(stm->expires)); } static inline enum flow_action_hw_stats tc_act_hw_stats(u8 hw_stats) -- 2.50.0.727.gbf7dc18ff4-goog