Re: [PATCH 1/3] net: ethernet: ti: cpdma: fix lockup in cpdma_ctlr_destroy()
From: Ivan Khoronzhuk <hidden>
Date: 2016-07-23 06:25:03
Also in:
linux-omap, lkml
On 22.07.16 16:58, Grygorii Strashko wrote:
quoted hunk ↗ jump to hunk
Fix deadlock in cpdma_ctlr_destroy() which is triggered now on cpsw module removal: cpsw_remove() - cpdma_ctlr_destroy() - spin_lock_irqsave(&ctlr->lock, flags) - cpdma_ctlr_stop() - spin_lock_irqsave(&ctlr->lock, flags); <- deadlock - cpdma_chan_destroy() - spin_lock_irqsave(&ctlr->lock, flags); <- deadlock The issue has not been observed before because CPDMA channels have been destroyed manually by CPSW until commit d941ebe88a41 ("net: ethernet: ti: cpsw: use destroy ctlr to destroy channels") was merged. Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> --- drivers/net/ethernet/ti/davinci_cpdma.c | 2 -- 1 file changed, 2 deletions(-)diff --git a/drivers/net/ethernet/ti/davinci_cpdma.c b/drivers/net/ethernet/ti/davinci_cpdma.c index a68652a..89242e9 100644 --- a/drivers/net/ethernet/ti/davinci_cpdma.c +++ b/drivers/net/ethernet/ti/davinci_cpdma.c@@ -436,7 +436,6 @@ int cpdma_ctlr_destroy(struct cpdma_ctlr *ctlr) if (!ctlr) return -EINVAL; - spin_lock_irqsave(&ctlr->lock, flags);
Should ctlr->state be checked under lock? Seems like here should be used unlocked static versions of cpdma_ctlr_stop() and cpdma_chan_destroy() instead.
quoted hunk ↗ jump to hunk
if (ctlr->state != CPDMA_STATE_IDLE) cpdma_ctlr_stop(ctlr);@@ -444,7 +443,6 @@ int cpdma_ctlr_destroy(struct cpdma_ctlr *ctlr) cpdma_chan_destroy(ctlr->channels[i]); cpdma_desc_pool_destroy(ctlr->pool); - spin_unlock_irqrestore(&ctlr->lock, flags); return ret; } EXPORT_SYMBOL_GPL(cpdma_ctlr_destroy);
-- Regards, Ivan Khoronzhuk