From ab5e290a86075c09201deb55c566f875ef4649d7 Mon Sep 17 00:00:00 2001 From: Sergey Ryazanov Date: Wed, 4 Mar 2015 05:12:11 +0300 Subject: [PATCH] ath5k: fix reset race To prepare for reset ath5k should finish all asynchronous tasks. At first, it disables the interrupt generation, then it waits for the interrupt handler and tasklets completion, and then proceeds to the HW configuration update. But it does not consider that the interrupt handler or tasklet re-enables the interrupt generation. And we fall in a situation when ath5k assumes that interrupts are disabled, but it is not. This can lead to different consequences, such as reception of the frame, when we do not expect it. Under certain circumstances, this can lead to the following warning: WARNING: at ath5k/base.c:589 ath5k_tasklet_rx+0x318/0x6ec [ath5k]() invalid hw_rix: 1a [..] Call Trace: [<802656a8>] show_stack+0x48/0x70 [<802dd92c>] warn_slowpath_common+0x88/0xbc [<802dd98c>] warn_slowpath_fmt+0x2c/0x38 [<81b51be8>] ath5k_tasklet_rx+0x318/0x6ec [ath5k] [<8028ac64>] tasklet_action+0x8c/0xf0 [<80075804>] __do_softirq+0x180/0x32c [<80196ce8>] irq_exit+0x54/0x70 [<80041848>] ret_from_irq+0x0/0x4 [<80182fdc>] ioread32+0x4/0xc [<81b4c42c>] ath5k_hw_set_sleep_clock+0x2ec/0x474 [ath5k] [<81b4cf28>] ath5k_hw_reset+0x50/0xeb8 [ath5k] [<81b50900>] ath5k_reset+0xd4/0x310 [ath5k] [<81b557e8>] ath5k_config+0x4c/0x104 [ath5k] [<80d01770>] ieee80211_hw_config+0x2f4/0x35c [mac80211] [<80d09aa8>] ieee80211_scan_work+0x2e4/0x414 [mac80211] [<8022c3f4>] process_one_work+0x28c/0x400 [<802df8f8>] worker_thread+0x258/0x3c0 [<801b5710>] kthread+0xe0/0xec [<800418a8>] ret_from_kernel_thread+0x14/0x1c Fix this issue by adding a new status flag, which forbids to re-enable the interrupt generation until the HW configuration is completed. Note: previous patch, which reorders the Rx disable code helps to avoid the above warning, but not fixes the root cause of unexpected frame receiving. CC: Jiri Slaby CC: Nick Kossifidis CC: Luis R. Rodriguez Reported-by: Christophe Prevotaux Tested-by: Christophe Prevotaux Tested-by: Eric Bree Signed-off-by: Sergey Ryazanov Signed-off-by: Kalle Valo --- drivers/net/wireless/ath/ath5k/ath5k.h | 1 + drivers/net/wireless/ath/ath5k/base.c | 7 +++++++ 2 files changed, 8 insertions(+) diff --git a/drivers/net/wireless/ath/ath5k/ath5k.h b/drivers/net/wireless/ath/ath5k/ath5k.h index 1ed7a88aeea9..7ca0d6f930fd 100644 --- a/drivers/net/wireless/ath/ath5k/ath5k.h +++ b/drivers/net/wireless/ath/ath5k/ath5k.h @@ -1283,6 +1283,7 @@ struct ath5k_hw { #define ATH_STAT_PROMISC 1 #define ATH_STAT_LEDSOFT 2 /* enable LED gpio status */ #define ATH_STAT_STARTED 3 /* opened & irqs enabled */ +#define ATH_STAT_RESET 4 /* hw reset */ unsigned int filter_flags; /* HW flags, AR5K_RX_FILTER_* */ unsigned int fif_filter_flags; /* Current FIF_* filter flags */ diff --git a/drivers/net/wireless/ath/ath5k/base.c b/drivers/net/wireless/ath/ath5k/base.c index c186963ad7c0..a6131825c9f6 100644 --- a/drivers/net/wireless/ath/ath5k/base.c +++ b/drivers/net/wireless/ath/ath5k/base.c @@ -1523,6 +1523,9 @@ ath5k_set_current_imask(struct ath5k_hw *ah) enum ath5k_int imask; unsigned long flags; + if (test_bit(ATH_STAT_RESET, ah->status)) + return; + spin_lock_irqsave(&ah->irqlock, flags); imask = ah->imask; if (ah->rx_pending) @@ -2862,6 +2865,8 @@ ath5k_reset(struct ath5k_hw *ah, struct ieee80211_channel *chan, ATH5K_DBG(ah, ATH5K_DEBUG_RESET, "resetting\n"); + __set_bit(ATH_STAT_RESET, ah->status); + ath5k_hw_set_imr(ah, 0); synchronize_irq(ah->irq); ath5k_stop_tasklets(ah); @@ -2952,6 +2957,8 @@ ath5k_reset(struct ath5k_hw *ah, struct ieee80211_channel *chan, */ /* ath5k_chan_change(ah, c); */ + __clear_bit(ATH_STAT_RESET, ah->status); + ath5k_beacon_config(ah); /* intrs are enabled by ath5k_beacon_config */ -- 2.20.1