The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x f1a0898b5d6a77d332d036da03bad6fa9770de5b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2023062633-grip-headway-6fcc@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From f1a0898b5d6a77d332d036da03bad6fa9770de5b Mon Sep 17 00:00:00 2001 From: Hugh Dickins hughd@google.com Date: Fri, 9 Jun 2023 14:29:39 -0700 Subject: [PATCH] wifi: iwlwifi: mvm: spin_lock_bh() to fix lockdep regression

Lockdep on 6.4-rc on ThinkPad X1 Carbon 5th says ===================================================== WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected 6.4.0-rc5 #1 Not tainted ----------------------------------------------------- kworker/3:1/49 [HC0[0]:SC0[4]:HE1:SE0] is trying to acquire: ffff8881066fa368 (&mvm_sta->deflink.lq_sta.rs_drv.pers.lock){+.+.}-{2:2}, at: rs_drv_get_rate+0x46/0xe7

and this task is already holding: ffff8881066f80a8 (&sta->rate_ctrl_lock){+.-.}-{2:2}, at: rate_control_get_rate+0xbd/0x126 which would create a new lock dependency: (&sta->rate_ctrl_lock){+.-.}-{2:2} -> (&mvm_sta->deflink.lq_sta.rs_drv.pers.lock){+.+.}-{2:2}

but this new dependency connects a SOFTIRQ-irq-safe lock: (&sta->rate_ctrl_lock){+.-.}-{2:2} etc. etc. etc.

Changing the spin_lock() in rs_drv_get_rate() to spin_lock_bh() was not enough to pacify lockdep, but changing them all on pers.lock has worked.

Fixes: a8938bc881d2 ("wifi: iwlwifi: mvm: Add locking to the rate read flow") Signed-off-by: Hugh Dickins hughd@google.com Link: https://lore.kernel.org/r/79ffcc22-9775-cb6d-3ffd-1a517c40beef@google.com Signed-off-by: Johannes Berg johannes.berg@intel.com

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/rs.c b/drivers/net/wireless/intel/iwlwifi/mvm/rs.c index 23266d0c9ce4..9a20468345e4 100644 --- a/drivers/net/wireless/intel/iwlwifi/mvm/rs.c +++ b/drivers/net/wireless/intel/iwlwifi/mvm/rs.c @@ -2692,7 +2692,7 @@ static void rs_drv_get_rate(void *mvm_r, struct ieee80211_sta *sta,

lq_sta = mvm_sta;

- spin_lock(&lq_sta->pers.lock); + spin_lock_bh(&lq_sta->pers.lock); iwl_mvm_hwrate_to_tx_rate_v1(lq_sta->last_rate_n_flags, info->band, &info->control.rates[0]); info->control.rates[0].count = 1; @@ -2707,7 +2707,7 @@ static void rs_drv_get_rate(void *mvm_r, struct ieee80211_sta *sta, iwl_mvm_hwrate_to_tx_rate_v1(last_ucode_rate, info->band, &txrc->reported_rate); } - spin_unlock(&lq_sta->pers.lock); + spin_unlock_bh(&lq_sta->pers.lock); }

static void *rs_drv_alloc_sta(void *mvm_rate, struct ieee80211_sta *sta, @@ -3264,11 +3264,11 @@ void iwl_mvm_rs_tx_status(struct iwl_mvm *mvm, struct ieee80211_sta *sta, /* If it's locked we are in middle of init flow * just wait for next tx status to update the lq_sta data */ - if (!spin_trylock(&mvmsta->deflink.lq_sta.rs_drv.pers.lock)) + if (!spin_trylock_bh(&mvmsta->deflink.lq_sta.rs_drv.pers.lock)) return;

__iwl_mvm_rs_tx_status(mvm, sta, tid, info, ndp); - spin_unlock(&mvmsta->deflink.lq_sta.rs_drv.pers.lock); + spin_unlock_bh(&mvmsta->deflink.lq_sta.rs_drv.pers.lock); }

#ifdef CONFIG_MAC80211_DEBUGFS @@ -4117,9 +4117,9 @@ void iwl_mvm_rs_rate_init(struct iwl_mvm *mvm, } else { struct iwl_mvm_sta *mvmsta = iwl_mvm_sta_from_mac80211(sta);

- spin_lock(&mvmsta->deflink.lq_sta.rs_drv.pers.lock); + spin_lock_bh(&mvmsta->deflink.lq_sta.rs_drv.pers.lock); rs_drv_rate_init(mvm, sta, band); - spin_unlock(&mvmsta->deflink.lq_sta.rs_drv.pers.lock); + spin_unlock_bh(&mvmsta->deflink.lq_sta.rs_drv.pers.lock); } }