On 07/12/2015 09:18 PM, Wengang Wang wrote: > Hi Doug, > > How do you think about this patch? Sorry, I picked this up already. I must have missed sending out the acknowledgment on this one. > thanks, > wengang > > 在 2015年07月06日 14:35, Wengang Wang 写道: >> Fixes: 3e0249f9c05c ("RDS/IB: add refcount tracking to struct >> rds_ib_device") >> >> There lacks a dropping on rds_ib_device.refcount in case rds_ib_alloc_fmr >> failed(mr pool running out). this lead to the refcount overflow. >> >> A complain in line 117(see following) is seen. From vmcore: >> s_ib_rdma_mr_pool_depleted is 2147485544 and rds_ibdev->refcount is >> -2147475448. >> That is the evidence the mr pool is used up. so rds_ib_alloc_fmr is >> very likely >> to return ERR_PTR(-EAGAIN). >> >> 115 void rds_ib_dev_put(struct rds_ib_device *rds_ibdev) >> 116 { >> 117 BUG_ON(atomic_read(&rds_ibdev->refcount) <= 0); >> 118 if (atomic_dec_and_test(&rds_ibdev->refcount)) >> 119 queue_work(rds_wq, &rds_ibdev->free_work); >> 120 } >> >> fix is to drop refcount when rds_ib_alloc_fmr failed. >> >> Signed-off-by: Wengang Wang >> Reviewed-by: Haggai Eran >> --- >> net/rds/ib_rdma.c | 4 +++- >> 1 file changed, 3 insertions(+), 1 deletion(-) >> >> diff --git a/net/rds/ib_rdma.c b/net/rds/ib_rdma.c >> index 273b8bf..657ba9f 100644 >> --- a/net/rds/ib_rdma.c >> +++ b/net/rds/ib_rdma.c >> @@ -759,8 +759,10 @@ void *rds_ib_get_mr(struct scatterlist *sg, >> unsigned long nents, >> } >> ibmr = rds_ib_alloc_fmr(rds_ibdev); >> - if (IS_ERR(ibmr)) >> + if (IS_ERR(ibmr)) { >> + rds_ib_dev_put(rds_ibdev); >> return ibmr; >> + } >> ret = rds_ib_map_fmr(rds_ibdev, ibmr, sg, nents); >> if (ret == 0) > > -- > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Doug Ledford GPG KeyID: 0E572FDD