This is a note to let you know that I've just added the patch titled

staging: rtl8723bs: Fix access-point mode deadlock

to my staging git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git in the staging-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 8f4347081be32e67b0873827e0138ab0fdaaf450 Mon Sep 17 00:00:00 2001 From: Hans de Goede hdegoede@redhat.com Date: Wed, 2 Mar 2022 11:16:36 +0100 Subject: staging: rtl8723bs: Fix access-point mode deadlock

Commit 54659ca026e5 ("staging: rtl8723bs: remove possible deadlock when disconnect (v2)") split the locking of pxmitpriv->lock vs sleep_q/lock into 2 locks in attempt to fix a lockdep reported issue with the locking order of the sta_hash_lock vs pxmitpriv->lock.

But in the end this turned out to not fully solve the sta_hash_lock issue so commit a7ac783c338b ("staging: rtl8723bs: remove a second possible deadlock") was added to fix this in another way.

The original fix was kept as it was still seen as a good thing to have, but now it turns out that it creates a deadlock in access-point mode:

[Feb20 23:47] ====================================================== [ +0.074085] WARNING: possible circular locking dependency detected [ +0.074077] 5.16.0-1-amd64 #1 Tainted: G C E [ +0.064710] ------------------------------------------------------ [ +0.074075] ksoftirqd/3/29 is trying to acquire lock: [ +0.060542] ffffb8b30062ab00 (&pxmitpriv->lock){+.-.}-{2:2}, at: rtw_xmit_classifier+0x8a/0x140 [r8723bs] [ +0.114921] but task is already holding lock: [ +0.069908] ffffb8b3007ab704 (&psta->sleep_q.lock){+.-.}-{2:2}, at: wakeup_sta_to_xmit+0x3b/0x300 [r8723bs] [ +0.116976] which lock already depends on the new lock.

[ +0.098037] the existing dependency chain (in reverse order) is: [ +0.089704] -> #1 (&psta->sleep_q.lock){+.-.}-{2:2}: [ +0.077232] _raw_spin_lock_bh+0x34/0x40 [ +0.053261] xmitframe_enqueue_for_sleeping_sta+0xc1/0x2f0 [r8723bs] [ +0.082572] rtw_xmit+0x58b/0x940 [r8723bs] [ +0.056528] _rtw_xmit_entry+0xba/0x350 [r8723bs] [ +0.062755] dev_hard_start_xmit+0xf1/0x320 [ +0.056381] sch_direct_xmit+0x9e/0x360 [ +0.052212] __dev_queue_xmit+0xce4/0x1080 [ +0.055334] ip6_finish_output2+0x18f/0x6e0 [ +0.056378] ndisc_send_skb+0x2c8/0x870 [ +0.052209] ndisc_send_ns+0xd3/0x210 [ +0.050130] addrconf_dad_work+0x3df/0x5a0 [ +0.055338] process_one_work+0x274/0x5a0 [ +0.054296] worker_thread+0x52/0x3b0 [ +0.050124] kthread+0x16c/0x1a0 [ +0.044925] ret_from_fork+0x1f/0x30 [ +0.049092] -> #0 (&pxmitpriv->lock){+.-.}-{2:2}: [ +0.074101] __lock_acquire+0x10f5/0x1d80 [ +0.054298] lock_acquire+0xd7/0x300 [ +0.049088] _raw_spin_lock_bh+0x34/0x40 [ +0.053248] rtw_xmit_classifier+0x8a/0x140 [r8723bs] [ +0.066949] rtw_xmitframe_enqueue+0xa/0x20 [r8723bs] [ +0.066946] rtl8723bs_hal_xmitframe_enqueue+0x14/0x50 [r8723bs] [ +0.078386] wakeup_sta_to_xmit+0xa6/0x300 [r8723bs] [ +0.065903] rtw_recv_entry+0xe36/0x1160 [r8723bs] [ +0.063809] rtl8723bs_recv_tasklet+0x349/0x6c0 [r8723bs] [ +0.071093] tasklet_action_common.constprop.0+0xe5/0x110 [ +0.070966] __do_softirq+0x16f/0x50a [ +0.050134] __irq_exit_rcu+0xeb/0x140 [ +0.051172] irq_exit_rcu+0xa/0x20 [ +0.047006] common_interrupt+0xb8/0xd0 [ +0.052214] asm_common_interrupt+0x1e/0x40 [ +0.056381] finish_task_switch.isra.0+0x100/0x3a0 [ +0.063670] __schedule+0x3ad/0xd20 [ +0.048047] schedule+0x4e/0xc0 [ +0.043880] smpboot_thread_fn+0xc4/0x220 [ +0.054298] kthread+0x16c/0x1a0 [ +0.044922] ret_from_fork+0x1f/0x30 [ +0.049088] other info that might help us debug this:

[ +0.095950] Possible unsafe locking scenario:

[ +0.070952] CPU0 CPU1 [ +0.054282] ---- ---- [ +0.054285] lock(&psta->sleep_q.lock); [ +0.047004] lock(&pxmitpriv->lock); [ +0.074082] lock(&psta->sleep_q.lock); [ +0.077209] lock(&pxmitpriv->lock); [ +0.043873] *** DEADLOCK ***

[ +0.070950] 1 lock held by ksoftirqd/3/29: [ +0.049082] #0: ffffb8b3007ab704 (&psta->sleep_q.lock){+.-.}-{2:2}, at: wakeup_sta_to_xmit+0x3b/0x300 [r8723bs]

Analysis shows that in hindsight the splitting of the lock was not a good idea, so revert this to fix the access-point mode deadlock.

Note this is a straight-forward revert done with git revert, the commented out "/* spin_lock_bh(&psta_bmc->sleep_q.lock); */" lines were part of the code before the reverted changes.

Fixes: 54659ca026e5 ("staging: rtl8723bs: remove possible deadlock when disconnect (v2)") Cc: stable stable@vger.kernel.org Cc: Fabio Aiuto fabioaiuto83@gmail.com Signed-off-by: Hans de Goede hdegoede@redhat.com BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=215542 Link: https://lore.kernel.org/r/20220302101637.26542-1-hdegoede@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/staging/rtl8723bs/core/rtw_mlme_ext.c | 7 ++++-- drivers/staging/rtl8723bs/core/rtw_recv.c | 10 ++++++--- drivers/staging/rtl8723bs/core/rtw_sta_mgt.c | 22 +++++++++---------- drivers/staging/rtl8723bs/core/rtw_xmit.c | 16 ++++++++------ .../staging/rtl8723bs/hal/rtl8723bs_xmit.c | 2 ++ 5 files changed, 33 insertions(+), 24 deletions(-)

diff --git a/drivers/staging/rtl8723bs/core/rtw_mlme_ext.c b/drivers/staging/rtl8723bs/core/rtw_mlme_ext.c index 0f82f5031c43..49a3f45cb771 100644 --- a/drivers/staging/rtl8723bs/core/rtw_mlme_ext.c +++ b/drivers/staging/rtl8723bs/core/rtw_mlme_ext.c @@ -5907,6 +5907,7 @@ u8 chk_bmc_sleepq_hdl(struct adapter *padapter, unsigned char *pbuf) struct sta_info *psta_bmc; struct list_head *xmitframe_plist, *xmitframe_phead, *tmp; struct xmit_frame *pxmitframe = NULL; + struct xmit_priv *pxmitpriv = &padapter->xmitpriv; struct sta_priv *pstapriv = &padapter->stapriv;

/* for BC/MC Frames */ @@ -5917,7 +5918,8 @@ u8 chk_bmc_sleepq_hdl(struct adapter *padapter, unsigned char *pbuf) if ((pstapriv->tim_bitmap&BIT(0)) && (psta_bmc->sleepq_len > 0)) { msleep(10);/* 10ms, ATIM(HIQ) Windows */

- spin_lock_bh(&psta_bmc->sleep_q.lock); + /* spin_lock_bh(&psta_bmc->sleep_q.lock); */ + spin_lock_bh(&pxmitpriv->lock);

xmitframe_phead = get_list_head(&psta_bmc->sleep_q); list_for_each_safe(xmitframe_plist, tmp, xmitframe_phead) { @@ -5940,7 +5942,8 @@ u8 chk_bmc_sleepq_hdl(struct adapter *padapter, unsigned char *pbuf) rtw_hal_xmitframe_enqueue(padapter, pxmitframe); }

- spin_unlock_bh(&psta_bmc->sleep_q.lock); + /* spin_unlock_bh(&psta_bmc->sleep_q.lock); */ + spin_unlock_bh(&pxmitpriv->lock);

/* check hi queue and bmc_sleepq */ rtw_chk_hi_queue_cmd(padapter); diff --git a/drivers/staging/rtl8723bs/core/rtw_recv.c b/drivers/staging/rtl8723bs/core/rtw_recv.c index 41bfca549c64..105fe0e3482a 100644 --- a/drivers/staging/rtl8723bs/core/rtw_recv.c +++ b/drivers/staging/rtl8723bs/core/rtw_recv.c @@ -957,8 +957,10 @@ static signed int validate_recv_ctrl_frame(struct adapter *padapter, union recv_ if ((psta->state&WIFI_SLEEP_STATE) && (pstapriv->sta_dz_bitmap&BIT(psta->aid))) { struct list_head *xmitframe_plist, *xmitframe_phead; struct xmit_frame *pxmitframe = NULL; + struct xmit_priv *pxmitpriv = &padapter->xmitpriv;

- spin_lock_bh(&psta->sleep_q.lock); + /* spin_lock_bh(&psta->sleep_q.lock); */ + spin_lock_bh(&pxmitpriv->lock);

xmitframe_phead = get_list_head(&psta->sleep_q); xmitframe_plist = get_next(xmitframe_phead); @@ -989,10 +991,12 @@ static signed int validate_recv_ctrl_frame(struct adapter *padapter, union recv_ update_beacon(padapter, WLAN_EID_TIM, NULL, true); }

- spin_unlock_bh(&psta->sleep_q.lock); + /* spin_unlock_bh(&psta->sleep_q.lock); */ + spin_unlock_bh(&pxmitpriv->lock);

} else { - spin_unlock_bh(&psta->sleep_q.lock); + /* spin_unlock_bh(&psta->sleep_q.lock); */ + spin_unlock_bh(&pxmitpriv->lock);

if (pstapriv->tim_bitmap&BIT(psta->aid)) { if (psta->sleepq_len == 0) { diff --git a/drivers/staging/rtl8723bs/core/rtw_sta_mgt.c b/drivers/staging/rtl8723bs/core/rtw_sta_mgt.c index 0c9ea1520fd0..beb11d89db18 100644 --- a/drivers/staging/rtl8723bs/core/rtw_sta_mgt.c +++ b/drivers/staging/rtl8723bs/core/rtw_sta_mgt.c @@ -293,48 +293,46 @@ u32 rtw_free_stainfo(struct adapter *padapter, struct sta_info *psta)

/* list_del_init(&psta->wakeup_list); */

- spin_lock_bh(&psta->sleep_q.lock); + spin_lock_bh(&pxmitpriv->lock); + rtw_free_xmitframe_queue(pxmitpriv, &psta->sleep_q); psta->sleepq_len = 0; - spin_unlock_bh(&psta->sleep_q.lock); - - spin_lock_bh(&pxmitpriv->lock);

/* vo */ - spin_lock_bh(&pstaxmitpriv->vo_q.sta_pending.lock); + /* spin_lock_bh(&(pxmitpriv->vo_pending.lock)); */ rtw_free_xmitframe_queue(pxmitpriv, &pstaxmitpriv->vo_q.sta_pending); list_del_init(&(pstaxmitpriv->vo_q.tx_pending)); phwxmit = pxmitpriv->hwxmits; phwxmit->accnt -= pstaxmitpriv->vo_q.qcnt; pstaxmitpriv->vo_q.qcnt = 0; - spin_unlock_bh(&pstaxmitpriv->vo_q.sta_pending.lock); + /* spin_unlock_bh(&(pxmitpriv->vo_pending.lock)); */

/* vi */ - spin_lock_bh(&pstaxmitpriv->vi_q.sta_pending.lock); + /* spin_lock_bh(&(pxmitpriv->vi_pending.lock)); */ rtw_free_xmitframe_queue(pxmitpriv, &pstaxmitpriv->vi_q.sta_pending); list_del_init(&(pstaxmitpriv->vi_q.tx_pending)); phwxmit = pxmitpriv->hwxmits+1; phwxmit->accnt -= pstaxmitpriv->vi_q.qcnt; pstaxmitpriv->vi_q.qcnt = 0; - spin_unlock_bh(&pstaxmitpriv->vi_q.sta_pending.lock); + /* spin_unlock_bh(&(pxmitpriv->vi_pending.lock)); */

/* be */ - spin_lock_bh(&pstaxmitpriv->be_q.sta_pending.lock); + /* spin_lock_bh(&(pxmitpriv->be_pending.lock)); */ rtw_free_xmitframe_queue(pxmitpriv, &pstaxmitpriv->be_q.sta_pending); list_del_init(&(pstaxmitpriv->be_q.tx_pending)); phwxmit = pxmitpriv->hwxmits+2; phwxmit->accnt -= pstaxmitpriv->be_q.qcnt; pstaxmitpriv->be_q.qcnt = 0; - spin_unlock_bh(&pstaxmitpriv->be_q.sta_pending.lock); + /* spin_unlock_bh(&(pxmitpriv->be_pending.lock)); */

/* bk */ - spin_lock_bh(&pstaxmitpriv->bk_q.sta_pending.lock); + /* spin_lock_bh(&(pxmitpriv->bk_pending.lock)); */ rtw_free_xmitframe_queue(pxmitpriv, &pstaxmitpriv->bk_q.sta_pending); list_del_init(&(pstaxmitpriv->bk_q.tx_pending)); phwxmit = pxmitpriv->hwxmits+3; phwxmit->accnt -= pstaxmitpriv->bk_q.qcnt; pstaxmitpriv->bk_q.qcnt = 0; - spin_unlock_bh(&pstaxmitpriv->bk_q.sta_pending.lock); + /* spin_unlock_bh(&(pxmitpriv->bk_pending.lock)); */

spin_unlock_bh(&pxmitpriv->lock);

diff --git a/drivers/staging/rtl8723bs/core/rtw_xmit.c b/drivers/staging/rtl8723bs/core/rtw_xmit.c index 13b8bd5ffabc..f466bfd248fb 100644 --- a/drivers/staging/rtl8723bs/core/rtw_xmit.c +++ b/drivers/staging/rtl8723bs/core/rtw_xmit.c @@ -1734,12 +1734,15 @@ void rtw_free_xmitframe_queue(struct xmit_priv *pxmitpriv, struct __queue *pfram struct list_head *plist, *phead, *tmp; struct xmit_frame *pxmitframe;

+ spin_lock_bh(&pframequeue->lock); + phead = get_list_head(pframequeue); list_for_each_safe(plist, tmp, phead) { pxmitframe = list_entry(plist, struct xmit_frame, list);

rtw_free_xmitframe(pxmitpriv, pxmitframe); } + spin_unlock_bh(&pframequeue->lock); }

s32 rtw_xmitframe_enqueue(struct adapter *padapter, struct xmit_frame *pxmitframe) @@ -1794,7 +1797,6 @@ s32 rtw_xmit_classifier(struct adapter *padapter, struct xmit_frame *pxmitframe) struct sta_info *psta; struct tx_servq *ptxservq; struct pkt_attrib *pattrib = &pxmitframe->attrib; - struct xmit_priv *xmit_priv = &padapter->xmitpriv; struct hw_xmit *phwxmits = padapter->xmitpriv.hwxmits; signed int res = _SUCCESS;

@@ -1812,14 +1814,12 @@ s32 rtw_xmit_classifier(struct adapter *padapter, struct xmit_frame *pxmitframe)

ptxservq = rtw_get_sta_pending(padapter, psta, pattrib->priority, (u8 *)(&ac_index));

- spin_lock_bh(&xmit_priv->lock); if (list_empty(&ptxservq->tx_pending)) list_add_tail(&ptxservq->tx_pending, get_list_head(phwxmits[ac_index].sta_queue));

list_add_tail(&pxmitframe->list, get_list_head(&ptxservq->sta_pending)); ptxservq->qcnt++; phwxmits[ac_index].accnt++; - spin_unlock_bh(&xmit_priv->lock);

exit:

@@ -2202,10 +2202,11 @@ void wakeup_sta_to_xmit(struct adapter *padapter, struct sta_info *psta) struct list_head *xmitframe_plist, *xmitframe_phead, *tmp; struct xmit_frame *pxmitframe = NULL; struct sta_priv *pstapriv = &padapter->stapriv; + struct xmit_priv *pxmitpriv = &padapter->xmitpriv;

psta_bmc = rtw_get_bcmc_stainfo(padapter);

- spin_lock_bh(&psta->sleep_q.lock); + spin_lock_bh(&pxmitpriv->lock);

xmitframe_phead = get_list_head(&psta->sleep_q); list_for_each_safe(xmitframe_plist, tmp, xmitframe_phead) { @@ -2306,7 +2307,7 @@ void wakeup_sta_to_xmit(struct adapter *padapter, struct sta_info *psta)

_exit:

- spin_unlock_bh(&psta->sleep_q.lock); + spin_unlock_bh(&pxmitpriv->lock);

if (update_mask) update_beacon(padapter, WLAN_EID_TIM, NULL, true); @@ -2318,8 +2319,9 @@ void xmit_delivery_enabled_frames(struct adapter *padapter, struct sta_info *pst struct list_head *xmitframe_plist, *xmitframe_phead, *tmp; struct xmit_frame *pxmitframe = NULL; struct sta_priv *pstapriv = &padapter->stapriv; + struct xmit_priv *pxmitpriv = &padapter->xmitpriv;

- spin_lock_bh(&psta->sleep_q.lock); + spin_lock_bh(&pxmitpriv->lock);

xmitframe_phead = get_list_head(&psta->sleep_q); list_for_each_safe(xmitframe_plist, tmp, xmitframe_phead) { @@ -2372,7 +2374,7 @@ void xmit_delivery_enabled_frames(struct adapter *padapter, struct sta_info *pst } }

- spin_unlock_bh(&psta->sleep_q.lock); + spin_unlock_bh(&pxmitpriv->lock); }

void enqueue_pending_xmitbuf(struct xmit_priv *pxmitpriv, struct xmit_buf *pxmitbuf) diff --git a/drivers/staging/rtl8723bs/hal/rtl8723bs_xmit.c b/drivers/staging/rtl8723bs/hal/rtl8723bs_xmit.c index b5d5e922231c..15810438a472 100644 --- a/drivers/staging/rtl8723bs/hal/rtl8723bs_xmit.c +++ b/drivers/staging/rtl8723bs/hal/rtl8723bs_xmit.c @@ -502,7 +502,9 @@ s32 rtl8723bs_hal_xmit( rtw_issue_addbareq_cmd(padapter, pxmitframe); }

+ spin_lock_bh(&pxmitpriv->lock); err = rtw_xmitframe_enqueue(padapter, pxmitframe); + spin_unlock_bh(&pxmitpriv->lock); if (err != _SUCCESS) { rtw_free_xmitframe(pxmitpriv, pxmitframe);