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Miller" , Jakub Kicinski , Wenjia Zhang , "D. Wythe" , Mahanta Jambigi , Tony Lu , Wen Gu , Eric Dumazet Cc: linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, netdev@vger.kernel.org, Simon Horman , linux-s390@vger.kernel.org References: <20260808-b4-disp-22f119e6-v2-0-61647601a6f3@proton.me> <20260808-b4-disp-22f119e6-v2-2-61647601a6f3@proton.me> Content-Language: en-US From: Sidraya Jayagond In-Reply-To: <20260808-b4-disp-22f119e6-v2-2-61647601a6f3@proton.me> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Authority-Analysis: v=2.4 cv=RsP16imK c=1 sm=1 tr=0 ts=6a7d5a74 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=IkcTkHD0fZMA:10 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=gtJVlIiFC0nkM8rK_MsA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-GUID: JyJy2-MNmNE5AK77qfuxE_C8m-eN9rTL X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODEzMDAzNiBTYWx0ZWRfXxKIRWwFGxtb9 vowUq0V2DwrVN4P3N/LReb++avlKQYoeNDI/fs/2VIYTv51w0+2Yw9xVMI9cI942IDnxKQOmdwB G/tCRqQA3ykTuowPh1+ysJCJE3D7elW5glEHCM/RjjXlSLoXf9ZXRYdajuYSY7W+QCwIqk6bEZo CMhP13z3lUk6iCYd05wG+6q60oOi7uo+QrCCRNFKjuzQv/9YhmutI6X3xLpCRLCM1zDsaRoJWq3 ed5xVY0zlsiSceJ9VzoD2Vc4j2F6XnV1MEUAbmP7T0aGB26qLN2pFJSVlAILD+VRLOk11D7oqDJ CJI1paOrLQBZoffCxZQmaRgXu/Qqmxcz9AHugFFIhFklxVLALJxX/+VHyb8BbyFW/u6YftbDhVw J6crKWt0hcxPjrRZs99MDPuOFwcXQeibq4NoJPZGn9cmMD4305OLcKA+h39MFyyqbbprokbu7/1 T+5GkhIMknxZCvD8U6w== X-Proofpoint-ORIG-GUID: zq2tARgAA9sCWM6IEnURL76Va5V9Nk1v X-Proofpoint-Spam-Info: AW1haW4tMjYwODEzMDAzNiBTYWx0ZWRfXwqW4UgQnevbK GO5XSBK+dSDpHFlUHNu9/y3XzRJuvVkBksfj5q3ZBjPKKfGHU8fvjCeqb9V+QwXOupJHhH7sdhy mFL+rIWppEnu+BvgbpZkBSsULMNIDKU= 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=2026-08-13_01,2026-08-12_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 impostorscore=0 suspectscore=0 clxscore=1015 malwarescore=0 phishscore=0 adultscore=0 lowpriorityscore=0 priorityscore=1501 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608130036 On 08/08/26 12:51 pm, Bryam Vargas via B4 Relay wrote: > From: Bryam Vargas > > smc_close_stream_wait() calls smc_tx_prepared_sends() from inside its > sk_wait_event() condition, and sk_wait_event() evaluates that condition > once with the socket lock released. smcd_buf_detach() clears > conn->sndbuf_desc from smc_conn_kill() under lock_sock(), so a link group > terminating while a socket waits there leaves the helper dereferencing > NULL, faulting out of close(). SIOCOUTQ reads the field by hand, and > smc_close_cancel_work() drops the lock across two cancel_*_sync() calls. > > Sample the pointer once in the helper, report nothing prepared while it is > unset, and bound the ioctl the same way. The receive tasklet dereferences > the field directly in smc_cdc_msg_recv_action(), not through this helper; > 1/2 is what keeps it from running that late. > > Fixes: ae2be35cbed2 ("net/smc: {at|de}tach sndbuf to peer DMB if supported") > Cc: stable@vger.kernel.org > Signed-off-by: Bryam Vargas > --- > net/smc/af_smc.c | 3 ++- > net/smc/smc_tx.h | 6 +++++- > 2 files changed, 7 insertions(+), 2 deletions(-) > > diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c > index 00403175b740..cff910cedbfc 100644 > --- a/net/smc/af_smc.c > +++ b/net/smc/af_smc.c > @@ -3233,7 +3233,8 @@ int smc_ioctl(struct socket *sock, unsigned int cmd, > return -EINVAL; > } > if (smc->sk.sk_state == SMC_INIT || > - smc->sk.sk_state == SMC_CLOSED) > + smc->sk.sk_state == SMC_CLOSED || > + !READ_ONCE(smc->conn.sndbuf_desc)) > answ = 0; > else > answ = smc->conn.sndbuf_desc->len - > diff --git a/net/smc/smc_tx.h b/net/smc/smc_tx.h > index a59f370b8b43..610a945aefd6 100644 > --- a/net/smc/smc_tx.h > +++ b/net/smc/smc_tx.h > @@ -20,11 +20,15 @@ > > static inline int smc_tx_prepared_sends(struct smc_connection *conn) > { > + struct smc_buf_desc *sndbuf_desc = READ_ONCE(conn->sndbuf_desc); > union smc_host_cursor sent, prep; > > + if (!sndbuf_desc) > + return 0; > + > smc_curs_copy(&sent, &conn->tx_curs_sent, conn); > smc_curs_copy(&prep, &conn->tx_curs_prep, conn); > - return smc_curs_diff(conn->sndbuf_desc->len, &sent, &prep); > + return smc_curs_diff(sndbuf_desc->len, &sent, &prep); > } > > void smc_tx_pending(struct smc_connection *conn); > Reviewed-by: Sidraya Jayagond