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- From: Emmanuel Grumbach <[email protected]>
- Date: Sun, 20 Dec 2015 13:50:00 +0200
- Subject: [PATCH] mac80211: fix PS-Poll handling
- My commit below broken PS-Poll handling. In case the driver
- has no frames buffered, driver_release_tids will be 0, but
- calling find_highest_prio_tid() with 0 as a parameter is
- not a good idea:
- fls(0) - 1 = -1.
- This bug caused mac80211 to think that frames were buffered
- in the driver which in turn was confused because mac80211
- was asking to release frames that were not reported to
- exist.
- On iwlwifi, this led to the WARNING below:
- WARNING: CPU: 0 PID: 11230 at drivers/net/wireless/intel/iwlwifi/mvm/sta.c:1733 iwl_mvm_sta_modify_sleep_tx_count+0x2af/0x320 [iwlmvm]()
- ffffffffc0627c60 ffff8800069b7648 ffffffff81888913 0000000000000000
- 0000000000000000 ffff8800069b7688 ffffffff81089d6a ffff8800069b7678
- 0000000000000001 ffff88003b35abf0 ffff88000698b128 ffff8800069b76d4
- Call Trace:
- [<ffffffff81888913>] dump_stack+0x4c/0x65
- [<ffffffff81089d6a>] warn_slowpath_common+0x8a/0xc0
- [<ffffffff81089e5a>] warn_slowpath_null+0x1a/0x20
- [<ffffffffc05f36bf>] iwl_mvm_sta_modify_sleep_tx_count+0x2af/0x320 [iwlmvm]
- [<ffffffffc05dae41>] iwl_mvm_mac_release_buffered_frames+0x31/0x40 [iwlmvm]
- [<ffffffffc045d8b6>] ieee80211_sta_ps_deliver_response+0x6e6/0xd80 [mac80211]
- [<ffffffffc0461296>] ieee80211_sta_ps_deliver_poll_response+0x26/0x30 [mac80211]
- [<ffffffffc048f743>] ieee80211_rx_handlers+0xa83/0x2900 [mac80211]
- [<ffffffffc04917ad>] ieee80211_prepare_and_rx_handle+0x1ed/0xa70 [mac80211]
- [<ffffffffc045e3d5>] ? sta_info_get_bss+0x5/0x4a0 [mac80211]
- [<ffffffffc04925b6>] ieee80211_rx_napi+0x586/0xcd0 [mac80211]
- [<ffffffffc05eaa3e>] iwl_mvm_rx_rx_mpdu+0x59e/0xc60 [iwlmvm]
- Fixes: 0ead2510f8ce ("mac80211: allow the driver to send EOSP when needed")
- Signed-off-by: Emmanuel Grumbach <[email protected]>
- ---
- --- a/net/mac80211/sta_info.c
- +++ b/net/mac80211/sta_info.c
- @@ -1453,7 +1453,7 @@ ieee80211_sta_ps_deliver_response(struct
-
- more_data = ieee80211_sta_ps_more_data(sta, ignored_acs, reason, driver_release_tids);
-
- - if (reason == IEEE80211_FRAME_RELEASE_PSPOLL)
- + if (driver_release_tids && reason == IEEE80211_FRAME_RELEASE_PSPOLL)
- driver_release_tids =
- BIT(find_highest_prio_tid(driver_release_tids));
-
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