Messages in this thread | | | Date | Thu, 4 Oct 2018 09:59:15 +0200 | From | Stanislaw Gruszka <> | Subject | Re: [PATCH] net: wireless: iwlegacy: Fix possible data races in il4965_send_rxon_assoc() |
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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.
> @@ -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
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