Re: [PATCH] net: wireless: iwlegacy: Fix possible data races in il4965_send_rxon_assoc()
From: Stanislaw Gruszka <hidden>
Date: 2018-10-04 07:59:19
Also in:
linux-wireless, lkml
On Wed, Oct 03, 2018 at 10:07:45PM +0800, Jia-Ju Bai wrote:
These possible races are detected by a runtime testing. To fix these races, the mutex lock is used in il4965_send_rxon_assoc() to protect the data.
Really ? I'm surprised by that, see below.
quoted hunk ↗ jump to hunk
@@ -1297,6 +1297,7 @@ il4965_send_rxon_assoc(struct il_priv *il) const struct il_rxon_cmd *rxon1 = &il->staging; const struct il_rxon_cmd *rxon2 = &il->active; + mutex_lock(&il->mutex); if (rxon1->flags == rxon2->flags &&
For 4965 driver il4965_send_rxon_assoc() is only called by il_mac_bss_info_changed() and il4965_commit_rxon(). il_mac_bss_info_changed() acquire il->mutex and callers of il4965_commit_rxon() acquire il->mutex (but I did not check all of them). So I wonder how this patch did not cause the deadlock ? Anyway what can be done is adding: lockdep_assert_held(&il->mutex); il4965_commit_rxon() to check if we hold the mutex. Thanks Stanislaw