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Wythe" , Dust Li , Sidraya Jayagond , Mahanta Jambigi , linux-rdma@vger.kernel.org, linux-s390@vger.kernel.org, netdev@vger.kernel.org Cc: Tony Lu , Wen Gu , Karsten Graul , Ursula Braun , Wenjia Zhang , linux-kernel@vger.kernel.org, stable@vger.kernel.org References: <20260804213917.3413525-1-gyf161023@gmail.com> Content-Language: en-GB From: Hidayathulla Khan I In-Reply-To: <20260804213917.3413525-1-gyf161023@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-Spam-Info: AW1haW4tMjYwODA1MDA0NyBTYWx0ZWRfXw40AjIgpsswE DKZ9jxK2i/2S1mWl9Pytm1dAADrpJGRN9UXejrGEqoocKkjs69QChBSKDPU8Il7oTKQ7mn03TEW OToKKrT7tqOLHoub1maSn2z4QNJUqq4= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODA1MDA0NyBTYWx0ZWRfX1SlNoHYxe1ok ckeAY6LdsH60nZuku9U3GLiNp6hcpqLqq/UVxq50Q+uTJu1U3Psmhi8chap2ypKXLCBlCkqmrvW C/d+88kxkssGPcg210HHFBaJPvhV9rRrqxtLkAUwT948fiVqs09Xgb5oixtN9AvX/oAdTxww+2D UPxNdGkUnXx/tM+/gTe9aDAisQV9kTd2LhMIpWiMjIWpFed7xMpnNv2h2WgoNo8gIkxv+VCPN0T 5KBLF3l7ulMwdAlYaH+n4xyvl/Ta1Oa0A0Sw2yN0ZgWO3Zawks8JXZ34VzAwvw+ktI9otcxwq0r YDKGR4mE87i+DfXEg+AUSFYVhaRm4ZL8HSfielg5DHFeer4SyUOUki3BX8eBxjKPmI5J/i7hg0U oHDHnzZrUK/t/DG41JdJlEWEqVvUxUzhABn45ulKPaBW1muYFV83sf5GCtoh5KQsvfqiJIHSRPY FqUUGbqK5Cr8dtl5IvA== X-Authority-Analysis: v=2.4 cv=SI1ykuvH c=1 sm=1 tr=0 ts=6a72d792 cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=IkcTkHD0fZMA:10 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=U7nrCbtTmkRpXpFmAIza:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=pGLkceISAAAA:8 a=h0Cf4ckhx-fnnXdm7CAA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-ORIG-GUID: hm7exjQLvOy1koeT6yIdPd4NvjDhjvs3 X-Proofpoint-GUID: LP8eRiaH7bek0YrRrjxMggDB2oLXQIqi X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-05_02,2026-08-04_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 bulkscore=0 suspectscore=0 impostorscore=0 spamscore=0 phishscore=0 priorityscore=1501 lowpriorityscore=0 adultscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608050047 Hi Yifei, Thanks for looking into this. Yes I have submitted a patch for the same issue. https://lore.kernel.org/netdev/20260804082800.498672-1-hidayath@linux.ibm.com/ Hidayath On 05/08/26 3:09 am, Yifei Gao wrote: > smc_switch_conns() takes a reference on the socket with sock_hold() before > dropping conns_lock to prefetch a tx slot. On success the reference is > released by the sock_put() after smc_switch_cursor(). When > smc_cdc_get_free_slot() fails, however, the function jumps straight to > err_out without a sock_put(), leaking the reference and leaving the socket > unreclaimable. During SMC-R link failover with an exhausted backup link > this leaks one reference per failing connection switch. > > Release the reference before jumping to err_out. The err_out label is also > reached from the smc_switch_cursor() failure path, which has already done > its own sock_put(), so the put must stay at the get_free_slot failure site > rather than at the label. > > Fixes: c6f02ebeea3a ("net/smc: switch connections to alternate link") > Cc: stable@vger.kernel.org > Assisted-by: Claude:claude-opus-4-8 > Signed-off-by: Yifei Gao > --- > net/smc/smc_core.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c > index cf6b620fef05..04c6ce608ec7 100644 > --- a/net/smc/smc_core.c > +++ b/net/smc/smc_core.c > @@ -1148,8 +1148,10 @@ struct smc_link *smc_switch_conns(struct smc_link_group *lgr, > read_unlock_bh(&lgr->conns_lock); > /* pre-fetch buffer outside of send_lock, might sleep */ > rc = smc_cdc_get_free_slot(conn, to_lnk, &wr_buf, NULL, &pend); > - if (rc) > + if (rc) { > + sock_put(&smc->sk); > goto err_out; > + } > /* avoid race with smcr_tx_sndbuf_nonempty() */ > spin_lock_bh(&conn->send_lock); > smc_switch_link_and_count(conn, to_lnk);