Re: [PATCH net] net/smc: Fix memory leak when using percpu refs

[Dust Li <dust.li@linux.alibaba.com>]

On 2024-10-10 11:56:24, Kai Shen wrote:
>This patch adds missing percpu_ref_exit when releasing percpu refs.
>When releasing percpu refs, percpu_ref_exit should be called.
>Otherwise, memory leak happens.
>
>Fixes: 79a22238b4f2 ("net/smc: Use percpu ref for wr tx reference")
>Signed-off-by: Kai Shen <KaiShen@linux.alibaba.com>

Reviewed-by: Dust Li <dust.li@linux.alibaba.com>


>---
> net/smc/smc_wr.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
>diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c
>index 0021065a600a..994c0cd4fddb 100644
>--- a/net/smc/smc_wr.c
>+++ b/net/smc/smc_wr.c
>@@ -648,8 +648,10 @@ void smc_wr_free_link(struct smc_link *lnk)
> 	smc_wr_tx_wait_no_pending_sends(lnk);
> 	percpu_ref_kill(&lnk->wr_reg_refs);
> 	wait_for_completion(&lnk->reg_ref_comp);
>+	percpu_ref_exit(&lnk->wr_reg_refs);
> 	percpu_ref_kill(&lnk->wr_tx_refs);
> 	wait_for_completion(&lnk->tx_ref_comp);
>+	percpu_ref_exit(&lnk->wr_tx_refs);
> 
> 	if (lnk->wr_rx_dma_addr) {
> 		ib_dma_unmap_single(ibdev, lnk->wr_rx_dma_addr,
>@@ -912,11 +914,13 @@ int smc_wr_create_link(struct smc_link *lnk)
> 	init_waitqueue_head(&lnk->wr_reg_wait);
> 	rc = percpu_ref_init(&lnk->wr_reg_refs, smcr_wr_reg_refs_free, 0, GFP_KERNEL);
> 	if (rc)
>-		goto dma_unmap;
>+		goto cancel_ref;
> 	init_completion(&lnk->reg_ref_comp);
> 	init_waitqueue_head(&lnk->wr_rx_empty_wait);
> 	return rc;
> 
>+cancel_ref:
>+	percpu_ref_exit(&lnk->wr_tx_refs);
> dma_unmap:
> 	if (lnk->wr_rx_v2_dma_addr) {
> 		ib_dma_unmap_single(ibdev, lnk->wr_rx_v2_dma_addr,
>-- 
>2.31.1
>