Re: [PATCH v2 1/4] net: ethernet: ti: cpdma: fix lockup in cpdma_ctlr_destroy()

[Mugunthan V N]

On Thursday 28 July 2016 11:20 PM, Grygorii Strashko wrote:
> Fix deadlock in cpdma_ctlr_destroy() which is triggered now on
> cpsw module removal:
>  cpsw_remove()
>  - cpdma_ctlr_destroy()
>- spin_lock_irqsave(>lock, flags)
>- cpdma_ctlr_stop()
>  - spin_lock_irqsave(>lock, flags);
>- cpdma_chan_destroy()
>  - spin_lock_irqsave(>lock, flags);
> 
> 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 

Reviewed-by: Mugunthan V N 

Regards
Mugunthan V N

[PATCH v2 1/4] net: ethernet: ti: cpdma: fix lockup in cpdma_ctlr_destroy()

[Grygorii Strashko]

Fix deadlock in cpdma_ctlr_destroy() which is triggered now on
cpsw module removal:
 cpsw_remove()
 - cpdma_ctlr_destroy()
   - spin_lock_irqsave(>lock, flags)
   - cpdma_ctlr_stop()
 - spin_lock_irqsave(>lock, flags);
   - cpdma_chan_destroy()
 - spin_lock_irqsave(>lock, flags);

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 
---
 drivers/net/ethernet/ti/davinci_cpdma.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/net/ethernet/ti/davinci_cpdma.c 
b/drivers/net/ethernet/ti/davinci_cpdma.c
index c8154ff..fdc0f4f 100644
--- a/drivers/net/ethernet/ti/davinci_cpdma.c
+++ b/drivers/net/ethernet/ti/davinci_cpdma.c
@@ -357,13 +357,11 @@ EXPORT_SYMBOL_GPL(cpdma_ctlr_stop);
 
 int cpdma_ctlr_destroy(struct cpdma_ctlr *ctlr)
 {
-   unsigned long flags;
int ret = 0, i;
 
if (!ctlr)
return -EINVAL;
 
-   spin_lock_irqsave(>lock, flags);
if (ctlr->state != CPDMA_STATE_IDLE)
cpdma_ctlr_stop(ctlr);
 
@@ -371,7 +369,6 @@ int cpdma_ctlr_destroy(struct cpdma_ctlr *ctlr)
cpdma_chan_destroy(ctlr->channels[i]);
 
cpdma_desc_pool_destroy(ctlr->pool);
-   spin_unlock_irqrestore(>lock, flags);
return ret;
 }
 EXPORT_SYMBOL_GPL(cpdma_ctlr_destroy);
-- 
2.9.2