[PATCH] ath9k: fix race conditions when stop device
From: Stanislaw Gruszka <hidden>
Date: 2011-01-25 13:08:52
Subsystem:
atheros ath generic utilities, qualcomm atheros ath9k wireless driver, the rest · Maintainers:
Jeff Johnson, Toke Høiland-Jørgensen, Linus Torvalds
We do not kill any scheduled tasklets when stopping device, that may cause usage of resources after free. Moreover we enable interrupts in tasklet function, so we could potentially end with interrupts enabled when driver is not ready to receive them. I think patch should fix Ben's kernel crash from: http://marc.info/?l=linux-wireless&m=129438358921501&w=2 Cc: stable@kernel.org Signed-off-by: Stanislaw Gruszka <redacted> --- drivers/net/wireless/ath/ath9k/init.c | 5 ----- drivers/net/wireless/ath/ath9k/main.c | 9 +++++++++ 2 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/drivers/net/wireless/ath/ath9k/init.c b/drivers/net/wireless/ath/ath9k/init.c
index 767d8b8..b3254a3 100644
--- a/drivers/net/wireless/ath/ath9k/init.c
+++ b/drivers/net/wireless/ath/ath9k/init.c@@ -598,8 +598,6 @@ err_btcoex: err_queues: ath9k_hw_deinit(ah); err_hw: - tasklet_kill(&sc->intr_tq); - tasklet_kill(&sc->bcon_tasklet); kfree(ah); sc->sc_ah = NULL;
@@ -807,9 +805,6 @@ static void ath9k_deinit_softc(struct ath_softc *sc) ath9k_hw_deinit(sc->sc_ah); - tasklet_kill(&sc->intr_tq); - tasklet_kill(&sc->bcon_tasklet); - kfree(sc->sc_ah); sc->sc_ah = NULL; }
diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index c03184e..42cfd96 100644
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c@@ -1320,6 +1320,9 @@ static void ath9k_stop(struct ieee80211_hw *hw) spin_lock_bh(&sc->sc_pcu_lock); + /* prevent tasklets to enable interrupts once we disable them */ + ah->imask &= ~ATH9K_INT_GLOBAL; + /* make sure h/w will not generate any interrupt * before setting the invalid flag. */ ath9k_hw_disable_interrupts(ah);
@@ -1337,6 +1340,12 @@ static void ath9k_stop(struct ieee80211_hw *hw) spin_unlock_bh(&sc->sc_pcu_lock); + /* we can now sync irq and kill any running tasklets, since we already + * disabled interrupts and not holding a spin lock */ + synchronize_irq(sc->irq); + tasklet_kill(&sc->intr_tq); + tasklet_kill(&sc->bcon_tasklet); + ath9k_ps_restore(sc); sc->ps_idle = true;
--
1.7.1