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authorFelix Fietkau <nbd@openwrt.org>2012-05-30 15:32:24 +0200
committerJohn W. Linville <linville@tuxdriver.com>2012-06-04 15:25:41 -0400
commitd8c7aae64cd2db5eccc631c29fa978a24fb1feef (patch)
treefc6eeb2c27ee3762f9fabb70278df1914ebae6ef /net
parent71ecfa1893034eeb1c93e02e22ee2ad26d080858 (diff)
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mac80211: add missing rcu_read_lock/unlock in agg-rx session timer
Fixes a lockdep warning: =================================================== [ INFO: suspicious rcu_dereference_check() usage. ] --------------------------------------------------- net/mac80211/agg-rx.c:148 invoked rcu_dereference_check() without protection! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 1 1 lock held by arecord/11226: #0: (&tid_agg_rx->session_timer){+.-...}, at: [<ffffffff81066bb0>] call_timer_fn+0x0/0x360 stack backtrace: Pid: 11226, comm: arecord Not tainted 3.1.0-kml #16 Call Trace: <IRQ> [<ffffffff81093454>] lockdep_rcu_dereference+0xa4/0xc0 [<ffffffffa02778c9>] sta_rx_agg_session_timer_expired+0xc9/0x110 [mac80211] [<ffffffffa0277800>] ? ieee80211_process_addba_resp+0x220/0x220 [mac80211] [<ffffffff81066c3a>] call_timer_fn+0x8a/0x360 [<ffffffff81066bb0>] ? init_timer_deferrable_key+0x30/0x30 [<ffffffff81477bb0>] ? _raw_spin_unlock_irq+0x30/0x70 [<ffffffff81067049>] run_timer_softirq+0x139/0x310 [<ffffffff81091d5e>] ? put_lock_stats.isra.25+0xe/0x40 [<ffffffff810922ac>] ? lock_release_holdtime.part.26+0xdc/0x160 [<ffffffffa0277800>] ? ieee80211_process_addba_resp+0x220/0x220 [mac80211] [<ffffffff8105cb78>] __do_softirq+0xc8/0x3c0 [<ffffffff8108f088>] ? tick_dev_program_event+0x48/0x110 [<ffffffff8108f16f>] ? tick_program_event+0x1f/0x30 [<ffffffff81153b15>] ? putname+0x35/0x50 [<ffffffff8147a43c>] call_softirq+0x1c/0x30 [<ffffffff81004c55>] do_softirq+0xa5/0xe0 [<ffffffff8105d1ee>] irq_exit+0xae/0xe0 [<ffffffff8147ac6b>] smp_apic_timer_interrupt+0x6b/0x98 [<ffffffff81479ab3>] apic_timer_interrupt+0x73/0x80 <EOI> [<ffffffff8146aac6>] ? free_debug_processing+0x1a1/0x1d5 [<ffffffff81153b15>] ? putname+0x35/0x50 [<ffffffff8146ab2b>] __slab_free+0x31/0x2ca [<ffffffff81477c3a>] ? _raw_spin_unlock_irqrestore+0x4a/0x90 [<ffffffff81253b8f>] ? __debug_check_no_obj_freed+0x15f/0x210 [<ffffffff81097054>] ? lock_release_nested+0x84/0xc0 [<ffffffff8113ec55>] ? kmem_cache_free+0x105/0x250 [<ffffffff81153b15>] ? putname+0x35/0x50 [<ffffffff81153b15>] ? putname+0x35/0x50 [<ffffffff8113ed8f>] kmem_cache_free+0x23f/0x250 [<ffffffff81153b15>] putname+0x35/0x50 [<ffffffff81146d8d>] do_sys_open+0x16d/0x1d0 [<ffffffff81146e10>] sys_open+0x20/0x30 [<ffffffff81478f42>] system_call_fastpath+0x16/0x1b Reported-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'net')
-rw-r--r--net/mac80211/agg-rx.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/net/mac80211/agg-rx.c b/net/mac80211/agg-rx.c
index 26ddb69..c649188 100644
--- a/net/mac80211/agg-rx.c
+++ b/net/mac80211/agg-rx.c
@@ -145,15 +145,20 @@ static void sta_rx_agg_session_timer_expired(unsigned long data)
struct tid_ampdu_rx *tid_rx;
unsigned long timeout;
+ rcu_read_lock();
tid_rx = rcu_dereference(sta->ampdu_mlme.tid_rx[*ptid]);
- if (!tid_rx)
+ if (!tid_rx) {
+ rcu_read_unlock();
return;
+ }
timeout = tid_rx->last_rx + TU_TO_JIFFIES(tid_rx->timeout);
if (time_is_after_jiffies(timeout)) {
mod_timer(&tid_rx->session_timer, timeout);
+ rcu_read_unlock();
return;
}
+ rcu_read_unlock();
#ifdef CONFIG_MAC80211_HT_DEBUG
printk(KERN_DEBUG "rx session timer expired on tid %d\n", (u16)*ptid);