Remove spinlock as atomic_t can be used instead. Note we use only 16
lower bits, upper bits are changed but we impilcilty cast to u16.
This fix possible deadlock on IBSS mode reproted by lockdep:
=================================
[ INFO: inconsistent lock state ]
3.4.0-wl+ #4 Not tainted
---------------------------------
inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.
kworker/u:2/30374 [HC0[0]:SC0[0]:HE1:SE1] takes:
(&(&intf->seqlock)->rlock){+.?...}, at: [<f9979a20>] rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
{IN-SOFTIRQ-W} state was registered at:
[<c04978ab>] __lock_acquire+0x47b/0x1050
[<c0498504>] lock_acquire+0x84/0xf0
[<c0835733>] _raw_spin_lock+0x33/0x40
[<f9979a20>] rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
[<f9979f2a>] rt2x00queue_write_tx_frame+0x1a/0x300 [rt2x00lib]
[<f997834f>] rt2x00mac_tx+0x7f/0x380 [rt2x00lib]
[<f98fe363>] __ieee80211_tx+0x1b3/0x300 [mac80211]
[<f98ffdf5>] ieee80211_tx+0x105/0x130 [mac80211]
[<f99000dd>] ieee80211_xmit+0xad/0x100 [mac80211]
[<f9900519>] ieee80211_subif_start_xmit+0x2d9/0x930 [mac80211]
[<c0782e87>] dev_hard_start_xmit+0x307/0x660
[<c079bb71>] sch_direct_xmit+0xa1/0x1e0
[<c0784bb3>] dev_queue_xmit+0x183/0x730
[<c078c27a>] neigh_resolve_output+0xfa/0x1e0
[<c07b436a>] ip_finish_output+0x24a/0x460
[<c07b4897>] ip_output+0xb7/0x100
[<c07b2d60>] ip_local_out+0x20/0x60
[<c07e01ff>] igmpv3_sendpack+0x4f/0x60
[<c07e108f>] igmp_ifc_timer_expire+0x29f/0x330
[<c04520fc>] run_timer_softirq+0x15c/0x2f0
[<c0449e3e>] __do_softirq+0xae/0x1e0
irq event stamp: 18380437
hardirqs last enabled at (18380437): [<c0526027>] __slab_alloc.clone.3+0x67/0x5f0
hardirqs last disabled at (18380436): [<c0525ff3>] __slab_alloc.clone.3+0x33/0x5f0
softirqs last enabled at (18377616): [<c0449eb3>] __do_softirq+0x123/0x1e0
softirqs last disabled at (18377611): [<c041278d>] do_softirq+0x9d/0xe0
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&(&intf->seqlock)->rlock);
<Interrupt>
lock(&(&intf->seqlock)->rlock);
*** DEADLOCK ***
4 locks held by kworker/u:2/30374:
#0: (wiphy_name(local->hw.wiphy)){++++.+}, at: [<c045cf99>] process_one_work+0x109/0x3f0
#1: ((&sdata->work)){+.+.+.}, at: [<c045cf99>] process_one_work+0x109/0x3f0
#2: (&ifibss->mtx){+.+.+.}, at: [<f98f005b>] ieee80211_ibss_work+0x1b/0x470 [mac80211]
#3: (&intf->beacon_skb_mutex){+.+...}, at: [<f997a644>] rt2x00queue_update_beacon+0x24/0x50 [rt2x00lib]
stack backtrace:
Pid: 30374, comm: kworker/u:2 Not tainted 3.4.0-wl+ #4
Call Trace:
[<c04962a6>] print_usage_bug+0x1f6/0x220
[<c0496a12>] mark_lock+0x2c2/0x300
[<c0495ff0>] ? check_usage_forwards+0xc0/0xc0
[<c04978ec>] __lock_acquire+0x4bc/0x1050
[<c0527890>] ? __kmalloc_track_caller+0x1c0/0x1d0
[<c0777fb6>] ? copy_skb_header+0x26/0x90
[<c0498504>] lock_acquire+0x84/0xf0
[<f9979a20>] ? rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
[<c0835733>] _raw_spin_lock+0x33/0x40
[<f9979a20>] ? rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
[<f9979a20>] rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
[<f997a5cf>] rt2x00queue_update_beacon_locked+0x5f/0xb0 [rt2x00lib]
[<f997a64d>] rt2x00queue_update_beacon+0x2d/0x50 [rt2x00lib]
[<f9977e3a>] rt2x00mac_bss_info_changed+0x1ca/0x200 [rt2x00lib]
[<f9977c70>] ? rt2x00mac_remove_interface+0x70/0x70 [rt2x00lib]
[<f98e4dd0>] ieee80211_bss_info_change_notify+0xe0/0x1d0 [mac80211]
[<f98ef7b8>] __ieee80211_sta_join_ibss+0x3b8/0x610 [mac80211]
[<c0496ab4>] ? mark_held_locks+0x64/0xc0
[<c0440012>] ? virt_efi_query_capsule_caps+0x12/0x50
[<f98efb09>] ieee80211_sta_join_ibss+0xf9/0x140 [mac80211]
[<f98f0456>] ieee80211_ibss_work+0x416/0x470 [mac80211]
[<c0496d8b>] ? trace_hardirqs_on+0xb/0x10
[<c077683b>] ? skb_dequeue+0x4b/0x70
[<f98f207f>] ieee80211_iface_work+0x13f/0x230 [mac80211]
[<c045cf99>] ? process_one_work+0x109/0x3f0
[<c045d015>] process_one_work+0x185/0x3f0
[<c045cf99>] ? process_one_work+0x109/0x3f0
[<f98f1f40>] ? ieee80211_teardown_sdata+0xa0/0xa0 [mac80211]
[<c045ed86>] worker_thread+0x116/0x270
[<c045ec70>] ? manage_workers+0x1e0/0x1e0
[<c0462f64>] kthread+0x84/0x90
[<c0462ee0>] ? __init_kthread_worker+0x60/0x60
[<c083d382>] kernel_thread_helper+0x6/0x10
Cc: [email protected]
Signed-off-by: Stanislaw Gruszka <[email protected]>
---
drivers/net/wireless/rt2x00/rt2x00.h | 3 +--
drivers/net/wireless/rt2x00/rt2x00mac.c | 1 -
drivers/net/wireless/rt2x00/rt2x00queue.c | 13 ++++++-------
3 files changed, 7 insertions(+), 10 deletions(-)
diff --git a/drivers/net/wireless/rt2x00/rt2x00.h b/drivers/net/wireless/rt2x00/rt2x00.h
index ca36ccc..8f75402 100644
--- a/drivers/net/wireless/rt2x00/rt2x00.h
+++ b/drivers/net/wireless/rt2x00/rt2x00.h
@@ -396,8 +396,7 @@ struct rt2x00_intf {
* for hardware which doesn't support hardware
* sequence counting.
*/
- spinlock_t seqlock;
- u16 seqno;
+ atomic_t seqno;
};
static inline struct rt2x00_intf* vif_to_intf(struct ieee80211_vif *vif)
diff --git a/drivers/net/wireless/rt2x00/rt2x00mac.c b/drivers/net/wireless/rt2x00/rt2x00mac.c
index ef8b984..4ff26c2 100644
--- a/drivers/net/wireless/rt2x00/rt2x00mac.c
+++ b/drivers/net/wireless/rt2x00/rt2x00mac.c
@@ -277,7 +277,6 @@ int rt2x00mac_add_interface(struct ieee80211_hw *hw,
else
rt2x00dev->intf_sta_count++;
- spin_lock_init(&intf->seqlock);
mutex_init(&intf->beacon_skb_mutex);
intf->beacon = entry;
diff --git a/drivers/net/wireless/rt2x00/rt2x00queue.c b/drivers/net/wireless/rt2x00/rt2x00queue.c
index 4c662ec..2fd8301 100644
--- a/drivers/net/wireless/rt2x00/rt2x00queue.c
+++ b/drivers/net/wireless/rt2x00/rt2x00queue.c
@@ -207,6 +207,7 @@ static void rt2x00queue_create_tx_descriptor_seq(struct rt2x00_dev *rt2x00dev,
struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
struct rt2x00_intf *intf = vif_to_intf(tx_info->control.vif);
+ u16 seqno;
if (!(tx_info->flags & IEEE80211_TX_CTL_ASSIGN_SEQ))
return;
@@ -238,15 +239,13 @@ static void rt2x00queue_create_tx_descriptor_seq(struct rt2x00_dev *rt2x00dev,
* sequence counting per-frame, since those will override the
* sequence counter given by mac80211.
*/
- spin_lock(&intf->seqlock);
-
if (test_bit(ENTRY_TXD_FIRST_FRAGMENT, &txdesc->flags))
- intf->seqno += 0x10;
- hdr->seq_ctrl &= cpu_to_le16(IEEE80211_SCTL_FRAG);
- hdr->seq_ctrl |= cpu_to_le16(intf->seqno);
-
- spin_unlock(&intf->seqlock);
+ seqno = atomic_add_return(0x10, &intf->seqno);
+ else
+ seqno = atomic_read(&intf->seqno);
+ hdr->seq_ctrl &= cpu_to_le16(IEEE80211_SCTL_FRAG);
+ hdr->seq_ctrl |= cpu_to_le16(seqno);
}
static void rt2x00queue_create_tx_descriptor_plcp(struct rt2x00_dev *rt2x00dev,
--
1.7.1
On Fri, Jun 1, 2012 at 11:29 AM, Stanislaw Gruszka <[email protected]> wrote:
> Remove spinlock as atomic_t can be used instead. Note we use only 16
> lower bits, upper bits are changed but we impilcilty cast to u16.
>
> This fix possible deadlock on IBSS mode reproted by lockdep:
>
> =================================
> [ INFO: inconsistent lock state ]
> 3.4.0-wl+ #4 Not tainted
> ---------------------------------
> inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.
> kworker/u:2/30374 [HC0[0]:SC0[0]:HE1:SE1] takes:
> ?(&(&intf->seqlock)->rlock){+.?...}, at: [<f9979a20>] rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
> {IN-SOFTIRQ-W} state was registered at:
> ?[<c04978ab>] __lock_acquire+0x47b/0x1050
> ?[<c0498504>] lock_acquire+0x84/0xf0
> ?[<c0835733>] _raw_spin_lock+0x33/0x40
> ?[<f9979a20>] rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
> ?[<f9979f2a>] rt2x00queue_write_tx_frame+0x1a/0x300 [rt2x00lib]
> ?[<f997834f>] rt2x00mac_tx+0x7f/0x380 [rt2x00lib]
> ?[<f98fe363>] __ieee80211_tx+0x1b3/0x300 [mac80211]
> ?[<f98ffdf5>] ieee80211_tx+0x105/0x130 [mac80211]
> ?[<f99000dd>] ieee80211_xmit+0xad/0x100 [mac80211]
> ?[<f9900519>] ieee80211_subif_start_xmit+0x2d9/0x930 [mac80211]
> ?[<c0782e87>] dev_hard_start_xmit+0x307/0x660
> ?[<c079bb71>] sch_direct_xmit+0xa1/0x1e0
> ?[<c0784bb3>] dev_queue_xmit+0x183/0x730
> ?[<c078c27a>] neigh_resolve_output+0xfa/0x1e0
> ?[<c07b436a>] ip_finish_output+0x24a/0x460
> ?[<c07b4897>] ip_output+0xb7/0x100
> ?[<c07b2d60>] ip_local_out+0x20/0x60
> ?[<c07e01ff>] igmpv3_sendpack+0x4f/0x60
> ?[<c07e108f>] igmp_ifc_timer_expire+0x29f/0x330
> ?[<c04520fc>] run_timer_softirq+0x15c/0x2f0
> ?[<c0449e3e>] __do_softirq+0xae/0x1e0
> irq event stamp: 18380437
> hardirqs last ?enabled at (18380437): [<c0526027>] __slab_alloc.clone.3+0x67/0x5f0
> hardirqs last disabled at (18380436): [<c0525ff3>] __slab_alloc.clone.3+0x33/0x5f0
> softirqs last ?enabled at (18377616): [<c0449eb3>] __do_softirq+0x123/0x1e0
> softirqs last disabled at (18377611): [<c041278d>] do_softirq+0x9d/0xe0
>
> other info that might help us debug this:
> ?Possible unsafe locking scenario:
>
> ? ? ? CPU0
> ? ? ? ----
> ?lock(&(&intf->seqlock)->rlock);
> ?<Interrupt>
> ? ?lock(&(&intf->seqlock)->rlock);
>
> ?*** DEADLOCK ***
>
> 4 locks held by kworker/u:2/30374:
> ?#0: ?(wiphy_name(local->hw.wiphy)){++++.+}, at: [<c045cf99>] process_one_work+0x109/0x3f0
> ?#1: ?((&sdata->work)){+.+.+.}, at: [<c045cf99>] process_one_work+0x109/0x3f0
> ?#2: ?(&ifibss->mtx){+.+.+.}, at: [<f98f005b>] ieee80211_ibss_work+0x1b/0x470 [mac80211]
> ?#3: ?(&intf->beacon_skb_mutex){+.+...}, at: [<f997a644>] rt2x00queue_update_beacon+0x24/0x50 [rt2x00lib]
>
> stack backtrace:
> Pid: 30374, comm: kworker/u:2 Not tainted 3.4.0-wl+ #4
> Call Trace:
> ?[<c04962a6>] print_usage_bug+0x1f6/0x220
> ?[<c0496a12>] mark_lock+0x2c2/0x300
> ?[<c0495ff0>] ? check_usage_forwards+0xc0/0xc0
> ?[<c04978ec>] __lock_acquire+0x4bc/0x1050
> ?[<c0527890>] ? __kmalloc_track_caller+0x1c0/0x1d0
> ?[<c0777fb6>] ? copy_skb_header+0x26/0x90
> ?[<c0498504>] lock_acquire+0x84/0xf0
> ?[<f9979a20>] ? rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
> ?[<c0835733>] _raw_spin_lock+0x33/0x40
> ?[<f9979a20>] ? rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
> ?[<f9979a20>] rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
> ?[<f997a5cf>] rt2x00queue_update_beacon_locked+0x5f/0xb0 [rt2x00lib]
> ?[<f997a64d>] rt2x00queue_update_beacon+0x2d/0x50 [rt2x00lib]
> ?[<f9977e3a>] rt2x00mac_bss_info_changed+0x1ca/0x200 [rt2x00lib]
> ?[<f9977c70>] ? rt2x00mac_remove_interface+0x70/0x70 [rt2x00lib]
> ?[<f98e4dd0>] ieee80211_bss_info_change_notify+0xe0/0x1d0 [mac80211]
> ?[<f98ef7b8>] __ieee80211_sta_join_ibss+0x3b8/0x610 [mac80211]
> ?[<c0496ab4>] ? mark_held_locks+0x64/0xc0
> ?[<c0440012>] ? virt_efi_query_capsule_caps+0x12/0x50
> ?[<f98efb09>] ieee80211_sta_join_ibss+0xf9/0x140 [mac80211]
> ?[<f98f0456>] ieee80211_ibss_work+0x416/0x470 [mac80211]
> ?[<c0496d8b>] ? trace_hardirqs_on+0xb/0x10
> ?[<c077683b>] ? skb_dequeue+0x4b/0x70
> ?[<f98f207f>] ieee80211_iface_work+0x13f/0x230 [mac80211]
> ?[<c045cf99>] ? process_one_work+0x109/0x3f0
> ?[<c045d015>] process_one_work+0x185/0x3f0
> ?[<c045cf99>] ? process_one_work+0x109/0x3f0
> ?[<f98f1f40>] ? ieee80211_teardown_sdata+0xa0/0xa0 [mac80211]
> ?[<c045ed86>] worker_thread+0x116/0x270
> ?[<c045ec70>] ? manage_workers+0x1e0/0x1e0
> ?[<c0462f64>] kthread+0x84/0x90
> ?[<c0462ee0>] ? __init_kthread_worker+0x60/0x60
> ?[<c083d382>] kernel_thread_helper+0x6/0x10
>
> Cc: [email protected]
> Signed-off-by: Stanislaw Gruszka <[email protected]>
Looks good to me. I always thought about removing the lock completely
but wasn't entirely sure if it is safe but using an atomic variable is
definitely safe and should also be a bit more optimized then using the
spinlock, at least on most platforms ...
Acked-by: Helmut Schaa <[email protected]>
> ---
> ?drivers/net/wireless/rt2x00/rt2x00.h ? ? ?| ? ?3 +--
> ?drivers/net/wireless/rt2x00/rt2x00mac.c ? | ? ?1 -
> ?drivers/net/wireless/rt2x00/rt2x00queue.c | ? 13 ++++++-------
> ?3 files changed, 7 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/net/wireless/rt2x00/rt2x00.h b/drivers/net/wireless/rt2x00/rt2x00.h
> index ca36ccc..8f75402 100644
> --- a/drivers/net/wireless/rt2x00/rt2x00.h
> +++ b/drivers/net/wireless/rt2x00/rt2x00.h
> @@ -396,8 +396,7 @@ struct rt2x00_intf {
> ? ? ? ? * for hardware which doesn't support hardware
> ? ? ? ? * sequence counting.
> ? ? ? ? */
> - ? ? ? spinlock_t seqlock;
> - ? ? ? u16 seqno;
> + ? ? ? atomic_t seqno;
> ?};
>
> ?static inline struct rt2x00_intf* vif_to_intf(struct ieee80211_vif *vif)
> diff --git a/drivers/net/wireless/rt2x00/rt2x00mac.c b/drivers/net/wireless/rt2x00/rt2x00mac.c
> index ef8b984..4ff26c2 100644
> --- a/drivers/net/wireless/rt2x00/rt2x00mac.c
> +++ b/drivers/net/wireless/rt2x00/rt2x00mac.c
> @@ -277,7 +277,6 @@ int rt2x00mac_add_interface(struct ieee80211_hw *hw,
> ? ? ? ?else
> ? ? ? ? ? ? ? ?rt2x00dev->intf_sta_count++;
>
> - ? ? ? spin_lock_init(&intf->seqlock);
> ? ? ? ?mutex_init(&intf->beacon_skb_mutex);
> ? ? ? ?intf->beacon = entry;
>
> diff --git a/drivers/net/wireless/rt2x00/rt2x00queue.c b/drivers/net/wireless/rt2x00/rt2x00queue.c
> index 4c662ec..2fd8301 100644
> --- a/drivers/net/wireless/rt2x00/rt2x00queue.c
> +++ b/drivers/net/wireless/rt2x00/rt2x00queue.c
> @@ -207,6 +207,7 @@ static void rt2x00queue_create_tx_descriptor_seq(struct rt2x00_dev *rt2x00dev,
> ? ? ? ?struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
> ? ? ? ?struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
> ? ? ? ?struct rt2x00_intf *intf = vif_to_intf(tx_info->control.vif);
> + ? ? ? u16 seqno;
>
> ? ? ? ?if (!(tx_info->flags & IEEE80211_TX_CTL_ASSIGN_SEQ))
> ? ? ? ? ? ? ? ?return;
> @@ -238,15 +239,13 @@ static void rt2x00queue_create_tx_descriptor_seq(struct rt2x00_dev *rt2x00dev,
> ? ? ? ? * sequence counting per-frame, since those will override the
> ? ? ? ? * sequence counter given by mac80211.
> ? ? ? ? */
> - ? ? ? spin_lock(&intf->seqlock);
> -
> ? ? ? ?if (test_bit(ENTRY_TXD_FIRST_FRAGMENT, &txdesc->flags))
> - ? ? ? ? ? ? ? intf->seqno += 0x10;
> - ? ? ? hdr->seq_ctrl &= cpu_to_le16(IEEE80211_SCTL_FRAG);
> - ? ? ? hdr->seq_ctrl |= cpu_to_le16(intf->seqno);
> -
> - ? ? ? spin_unlock(&intf->seqlock);
> + ? ? ? ? ? ? ? seqno = atomic_add_return(0x10, &intf->seqno);
> + ? ? ? else
> + ? ? ? ? ? ? ? seqno = atomic_read(&intf->seqno);
>
> + ? ? ? hdr->seq_ctrl &= cpu_to_le16(IEEE80211_SCTL_FRAG);
> + ? ? ? hdr->seq_ctrl |= cpu_to_le16(seqno);
> ?}
>
> ?static void rt2x00queue_create_tx_descriptor_plcp(struct rt2x00_dev *rt2x00dev,
> --
> 1.7.1
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
> the body of a message to [email protected]
> More majordomo info at ?http://vger.kernel.org/majordomo-info.html
On 06/01/12 11:29, Stanislaw Gruszka wrote:
> Remove spinlock as atomic_t can be used instead. Note we use only 16
> lower bits, upper bits are changed but we impilcilty cast to u16.
>
> This fix possible deadlock on IBSS mode reproted by lockdep:
>
> =================================
> [ INFO: inconsistent lock state ]
> 3.4.0-wl+ #4 Not tainted
> ---------------------------------
> inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.
> kworker/u:2/30374 [HC0[0]:SC0[0]:HE1:SE1] takes:
> (&(&intf->seqlock)->rlock){+.?...}, at: [<f9979a20>] rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
> {IN-SOFTIRQ-W} state was registered at:
> [<c04978ab>] __lock_acquire+0x47b/0x1050
> [<c0498504>] lock_acquire+0x84/0xf0
> [<c0835733>] _raw_spin_lock+0x33/0x40
> [<f9979a20>] rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
> [<f9979f2a>] rt2x00queue_write_tx_frame+0x1a/0x300 [rt2x00lib]
> [<f997834f>] rt2x00mac_tx+0x7f/0x380 [rt2x00lib]
> [<f98fe363>] __ieee80211_tx+0x1b3/0x300 [mac80211]
> [<f98ffdf5>] ieee80211_tx+0x105/0x130 [mac80211]
> [<f99000dd>] ieee80211_xmit+0xad/0x100 [mac80211]
> [<f9900519>] ieee80211_subif_start_xmit+0x2d9/0x930 [mac80211]
> [<c0782e87>] dev_hard_start_xmit+0x307/0x660
> [<c079bb71>] sch_direct_xmit+0xa1/0x1e0
> [<c0784bb3>] dev_queue_xmit+0x183/0x730
> [<c078c27a>] neigh_resolve_output+0xfa/0x1e0
> [<c07b436a>] ip_finish_output+0x24a/0x460
> [<c07b4897>] ip_output+0xb7/0x100
> [<c07b2d60>] ip_local_out+0x20/0x60
> [<c07e01ff>] igmpv3_sendpack+0x4f/0x60
> [<c07e108f>] igmp_ifc_timer_expire+0x29f/0x330
> [<c04520fc>] run_timer_softirq+0x15c/0x2f0
> [<c0449e3e>] __do_softirq+0xae/0x1e0
> irq event stamp: 18380437
> hardirqs last enabled at (18380437): [<c0526027>] __slab_alloc.clone.3+0x67/0x5f0
> hardirqs last disabled at (18380436): [<c0525ff3>] __slab_alloc.clone.3+0x33/0x5f0
> softirqs last enabled at (18377616): [<c0449eb3>] __do_softirq+0x123/0x1e0
> softirqs last disabled at (18377611): [<c041278d>] do_softirq+0x9d/0xe0
>
> other info that might help us debug this:
> Possible unsafe locking scenario:
>
> CPU0
> ----
> lock(&(&intf->seqlock)->rlock);
> <Interrupt>
> lock(&(&intf->seqlock)->rlock);
>
> *** DEADLOCK ***
>
> 4 locks held by kworker/u:2/30374:
> #0: (wiphy_name(local->hw.wiphy)){++++.+}, at: [<c045cf99>] process_one_work+0x109/0x3f0
> #1: ((&sdata->work)){+.+.+.}, at: [<c045cf99>] process_one_work+0x109/0x3f0
> #2: (&ifibss->mtx){+.+.+.}, at: [<f98f005b>] ieee80211_ibss_work+0x1b/0x470 [mac80211]
> #3: (&intf->beacon_skb_mutex){+.+...}, at: [<f997a644>] rt2x00queue_update_beacon+0x24/0x50 [rt2x00lib]
>
> stack backtrace:
> Pid: 30374, comm: kworker/u:2 Not tainted 3.4.0-wl+ #4
> Call Trace:
> [<c04962a6>] print_usage_bug+0x1f6/0x220
> [<c0496a12>] mark_lock+0x2c2/0x300
> [<c0495ff0>] ? check_usage_forwards+0xc0/0xc0
> [<c04978ec>] __lock_acquire+0x4bc/0x1050
> [<c0527890>] ? __kmalloc_track_caller+0x1c0/0x1d0
> [<c0777fb6>] ? copy_skb_header+0x26/0x90
> [<c0498504>] lock_acquire+0x84/0xf0
> [<f9979a20>] ? rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
> [<c0835733>] _raw_spin_lock+0x33/0x40
> [<f9979a20>] ? rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
> [<f9979a20>] rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
> [<f997a5cf>] rt2x00queue_update_beacon_locked+0x5f/0xb0 [rt2x00lib]
> [<f997a64d>] rt2x00queue_update_beacon+0x2d/0x50 [rt2x00lib]
> [<f9977e3a>] rt2x00mac_bss_info_changed+0x1ca/0x200 [rt2x00lib]
> [<f9977c70>] ? rt2x00mac_remove_interface+0x70/0x70 [rt2x00lib]
> [<f98e4dd0>] ieee80211_bss_info_change_notify+0xe0/0x1d0 [mac80211]
> [<f98ef7b8>] __ieee80211_sta_join_ibss+0x3b8/0x610 [mac80211]
> [<c0496ab4>] ? mark_held_locks+0x64/0xc0
> [<c0440012>] ? virt_efi_query_capsule_caps+0x12/0x50
> [<f98efb09>] ieee80211_sta_join_ibss+0xf9/0x140 [mac80211]
> [<f98f0456>] ieee80211_ibss_work+0x416/0x470 [mac80211]
> [<c0496d8b>] ? trace_hardirqs_on+0xb/0x10
> [<c077683b>] ? skb_dequeue+0x4b/0x70
> [<f98f207f>] ieee80211_iface_work+0x13f/0x230 [mac80211]
> [<c045cf99>] ? process_one_work+0x109/0x3f0
> [<c045d015>] process_one_work+0x185/0x3f0
> [<c045cf99>] ? process_one_work+0x109/0x3f0
> [<f98f1f40>] ? ieee80211_teardown_sdata+0xa0/0xa0 [mac80211]
> [<c045ed86>] worker_thread+0x116/0x270
> [<c045ec70>] ? manage_workers+0x1e0/0x1e0
> [<c0462f64>] kthread+0x84/0x90
> [<c0462ee0>] ? __init_kthread_worker+0x60/0x60
> [<c083d382>] kernel_thread_helper+0x6/0x10
>
> Cc: [email protected]
> Signed-off-by: Stanislaw Gruszka <[email protected]>
Acked-by: Gertjan van Wingerde <[email protected]>
> ---
> drivers/net/wireless/rt2x00/rt2x00.h | 3 +--
> drivers/net/wireless/rt2x00/rt2x00mac.c | 1 -
> drivers/net/wireless/rt2x00/rt2x00queue.c | 13 ++++++-------
> 3 files changed, 7 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/net/wireless/rt2x00/rt2x00.h b/drivers/net/wireless/rt2x00/rt2x00.h
> index ca36ccc..8f75402 100644
> --- a/drivers/net/wireless/rt2x00/rt2x00.h
> +++ b/drivers/net/wireless/rt2x00/rt2x00.h
> @@ -396,8 +396,7 @@ struct rt2x00_intf {
> * for hardware which doesn't support hardware
> * sequence counting.
> */
> - spinlock_t seqlock;
> - u16 seqno;
> + atomic_t seqno;
> };
>
> static inline struct rt2x00_intf* vif_to_intf(struct ieee80211_vif *vif)
> diff --git a/drivers/net/wireless/rt2x00/rt2x00mac.c b/drivers/net/wireless/rt2x00/rt2x00mac.c
> index ef8b984..4ff26c2 100644
> --- a/drivers/net/wireless/rt2x00/rt2x00mac.c
> +++ b/drivers/net/wireless/rt2x00/rt2x00mac.c
> @@ -277,7 +277,6 @@ int rt2x00mac_add_interface(struct ieee80211_hw *hw,
> else
> rt2x00dev->intf_sta_count++;
>
> - spin_lock_init(&intf->seqlock);
> mutex_init(&intf->beacon_skb_mutex);
> intf->beacon = entry;
>
> diff --git a/drivers/net/wireless/rt2x00/rt2x00queue.c b/drivers/net/wireless/rt2x00/rt2x00queue.c
> index 4c662ec..2fd8301 100644
> --- a/drivers/net/wireless/rt2x00/rt2x00queue.c
> +++ b/drivers/net/wireless/rt2x00/rt2x00queue.c
> @@ -207,6 +207,7 @@ static void rt2x00queue_create_tx_descriptor_seq(struct rt2x00_dev *rt2x00dev,
> struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
> struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
> struct rt2x00_intf *intf = vif_to_intf(tx_info->control.vif);
> + u16 seqno;
>
> if (!(tx_info->flags & IEEE80211_TX_CTL_ASSIGN_SEQ))
> return;
> @@ -238,15 +239,13 @@ static void rt2x00queue_create_tx_descriptor_seq(struct rt2x00_dev *rt2x00dev,
> * sequence counting per-frame, since those will override the
> * sequence counter given by mac80211.
> */
> - spin_lock(&intf->seqlock);
> -
> if (test_bit(ENTRY_TXD_FIRST_FRAGMENT, &txdesc->flags))
> - intf->seqno += 0x10;
> - hdr->seq_ctrl &= cpu_to_le16(IEEE80211_SCTL_FRAG);
> - hdr->seq_ctrl |= cpu_to_le16(intf->seqno);
> -
> - spin_unlock(&intf->seqlock);
> + seqno = atomic_add_return(0x10, &intf->seqno);
> + else
> + seqno = atomic_read(&intf->seqno);
>
> + hdr->seq_ctrl &= cpu_to_le16(IEEE80211_SCTL_FRAG);
> + hdr->seq_ctrl |= cpu_to_le16(seqno);
> }
>
> static void rt2x00queue_create_tx_descriptor_plcp(struct rt2x00_dev *rt2x00dev,
--
---
Gertjan