| Message ID | 20161213170807.4853-1-tobias.johannes.klausmann@mni.thm.de (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | d1f1c0e289e1bc46cd6873ba6dd6c627f459e7fa |
| Delegated to: | Kalle Valo |
| Headers | show |
On 2016-12-13 18:08, Tobias Klausmann wrote: > Starting with commit d94a461d7a7d ("ath9k: use ieee80211_tx_status_noskb > where possible") the driver uses rcu_read_lock() && rcu_read_unlock(), yet on > returning early in ath_tx_edma_tasklet() the unlock is missing leading to stalls > and suspicious RCU usage: > > =============================== > [ INFO: suspicious RCU usage. ] > 4.9.0-rc8 #11 Not tainted > ------------------------------- > kernel/rcu/tree.c:705 Illegal idle entry in RCU read-side critical section.! > > other info that might help us debug this: > > RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 0 > RCU used illegally from extended quiescent state! > 1 lock held by swapper/7/0: > #0: > ( > rcu_read_lock > ){......} > , at: > [<ffffffffa06ed110>] ath_tx_edma_tasklet+0x0/0x450 [ath9k] > > stack backtrace: > CPU: 7 PID: 0 Comm: swapper/7 Not tainted 4.9.0-rc8 #11 > Hardware name: Acer Aspire V3-571G/VA50_HC_CR, BIOS V2.21 12/16/2013 > ffff88025efc3f38 ffffffff8132b1e5 ffff88017ede4540 0000000000000001 > ffff88025efc3f68 ffffffff810a25f7 ffff88025efcee60 ffff88017edebdd8 > ffff88025eeb5400 0000000000000091 ffff88025efc3f88 ffffffff810c3cd4 > Call Trace: > <IRQ> > [<ffffffff8132b1e5>] dump_stack+0x68/0x93 > [<ffffffff810a25f7>] lockdep_rcu_suspicious+0xd7/0x110 > [<ffffffff810c3cd4>] rcu_eqs_enter_common.constprop.85+0x154/0x200 > [<ffffffff810c5a54>] rcu_irq_exit+0x44/0xa0 > [<ffffffff81058631>] irq_exit+0x61/0xd0 > [<ffffffff81018d25>] do_IRQ+0x65/0x110 > [<ffffffff81672189>] common_interrupt+0x89/0x89 > <EOI> > [<ffffffff814ffe11>] ? cpuidle_enter_state+0x151/0x200 > [<ffffffff814ffee2>] cpuidle_enter+0x12/0x20 > [<ffffffff8109a6ae>] call_cpuidle+0x1e/0x40 > [<ffffffff8109a8f6>] cpu_startup_entry+0x146/0x220 > [<ffffffff810336f8>] start_secondary+0x148/0x170 > > Signed-off-by: Tobias Klausmann <tobias.johannes.klausmann@mni.thm.de> > Fixes: d94a461d7a7d ("ath9k: use ieee80211_tx_status_noskb where possible") > Cc: <stable@vger.kernel.org> # v4.9 Acked-by: Felix Fietkau <nbd@nbd.name>
Tobias Klausmann <tobias.johannes.klausmann@mni.thm.de> wrote: > Starting with commit d94a461d7a7d ("ath9k: use ieee80211_tx_status_noskb > where possible") the driver uses rcu_read_lock() && rcu_read_unlock(), yet on > returning early in ath_tx_edma_tasklet() the unlock is missing leading to stalls > and suspicious RCU usage: > > =============================== > [ INFO: suspicious RCU usage. ] > 4.9.0-rc8 #11 Not tainted > ------------------------------- > kernel/rcu/tree.c:705 Illegal idle entry in RCU read-side critical section.! > > other info that might help us debug this: > > RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 0 > RCU used illegally from extended quiescent state! > 1 lock held by swapper/7/0: > #0: > ( > rcu_read_lock > ){......} > , at: > [<ffffffffa06ed110>] ath_tx_edma_tasklet+0x0/0x450 [ath9k] > > stack backtrace: > CPU: 7 PID: 0 Comm: swapper/7 Not tainted 4.9.0-rc8 #11 > Hardware name: Acer Aspire V3-571G/VA50_HC_CR, BIOS V2.21 12/16/2013 > ffff88025efc3f38 ffffffff8132b1e5 ffff88017ede4540 0000000000000001 > ffff88025efc3f68 ffffffff810a25f7 ffff88025efcee60 ffff88017edebdd8 > ffff88025eeb5400 0000000000000091 ffff88025efc3f88 ffffffff810c3cd4 > Call Trace: > <IRQ> > [<ffffffff8132b1e5>] dump_stack+0x68/0x93 > [<ffffffff810a25f7>] lockdep_rcu_suspicious+0xd7/0x110 > [<ffffffff810c3cd4>] rcu_eqs_enter_common.constprop.85+0x154/0x200 > [<ffffffff810c5a54>] rcu_irq_exit+0x44/0xa0 > [<ffffffff81058631>] irq_exit+0x61/0xd0 > [<ffffffff81018d25>] do_IRQ+0x65/0x110 > [<ffffffff81672189>] common_interrupt+0x89/0x89 > <EOI> > [<ffffffff814ffe11>] ? cpuidle_enter_state+0x151/0x200 > [<ffffffff814ffee2>] cpuidle_enter+0x12/0x20 > [<ffffffff8109a6ae>] call_cpuidle+0x1e/0x40 > [<ffffffff8109a8f6>] cpu_startup_entry+0x146/0x220 > [<ffffffff810336f8>] start_secondary+0x148/0x170 > > Signed-off-by: Tobias Klausmann <tobias.johannes.klausmann@mni.thm.de> > Fixes: d94a461d7a7d ("ath9k: use ieee80211_tx_status_noskb where possible") > Cc: <stable@vger.kernel.org> # v4.9 > Acked-by: Felix Fietkau <nbd@nbd.name> Patch applied to ath-current branch of ath.git, thanks. d1f1c0e289e1 ath9k: do not return early to fix rcu unlocking
diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c index 52bfbb988611..e47286bf378e 100644 --- a/drivers/net/wireless/ath/ath9k/xmit.c +++ b/drivers/net/wireless/ath/ath9k/xmit.c @@ -2787,7 +2787,7 @@ void ath_tx_edma_tasklet(struct ath_softc *sc) fifo_list = &txq->txq_fifo[txq->txq_tailidx]; if (list_empty(fifo_list)) { ath_txq_unlock(sc, txq); - return; + break; } bf = list_first_entry(fifo_list, struct ath_buf, list);
Starting with commit d94a461d7a7d ("ath9k: use ieee80211_tx_status_noskb where possible") the driver uses rcu_read_lock() && rcu_read_unlock(), yet on returning early in ath_tx_edma_tasklet() the unlock is missing leading to stalls and suspicious RCU usage: =============================== [ INFO: suspicious RCU usage. ] 4.9.0-rc8 #11 Not tainted ------------------------------- kernel/rcu/tree.c:705 Illegal idle entry in RCU read-side critical section.! other info that might help us debug this: RCU used illegally from idle CPU! rcu_scheduler_active = 1, debug_locks = 0 RCU used illegally from extended quiescent state! 1 lock held by swapper/7/0: #0: ( rcu_read_lock ){......} , at: [<ffffffffa06ed110>] ath_tx_edma_tasklet+0x0/0x450 [ath9k] stack backtrace: CPU: 7 PID: 0 Comm: swapper/7 Not tainted 4.9.0-rc8 #11 Hardware name: Acer Aspire V3-571G/VA50_HC_CR, BIOS V2.21 12/16/2013 ffff88025efc3f38 ffffffff8132b1e5 ffff88017ede4540 0000000000000001 ffff88025efc3f68 ffffffff810a25f7 ffff88025efcee60 ffff88017edebdd8 ffff88025eeb5400 0000000000000091 ffff88025efc3f88 ffffffff810c3cd4 Call Trace: <IRQ> [<ffffffff8132b1e5>] dump_stack+0x68/0x93 [<ffffffff810a25f7>] lockdep_rcu_suspicious+0xd7/0x110 [<ffffffff810c3cd4>] rcu_eqs_enter_common.constprop.85+0x154/0x200 [<ffffffff810c5a54>] rcu_irq_exit+0x44/0xa0 [<ffffffff81058631>] irq_exit+0x61/0xd0 [<ffffffff81018d25>] do_IRQ+0x65/0x110 [<ffffffff81672189>] common_interrupt+0x89/0x89 <EOI> [<ffffffff814ffe11>] ? cpuidle_enter_state+0x151/0x200 [<ffffffff814ffee2>] cpuidle_enter+0x12/0x20 [<ffffffff8109a6ae>] call_cpuidle+0x1e/0x40 [<ffffffff8109a8f6>] cpu_startup_entry+0x146/0x220 [<ffffffff810336f8>] start_secondary+0x148/0x170 Signed-off-by: Tobias Klausmann <tobias.johannes.klausmann@mni.thm.de> Fixes: d94a461d7a7d ("ath9k: use ieee80211_tx_status_noskb where possible") Cc: <stable@vger.kernel.org> # v4.9 --- v2: break instead of unlock (rename patch) [Felix Fietkau], fix reference to commit [Kalle Valo] --- drivers/net/wireless/ath/ath9k/xmit.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)