From a364a7c168d0a0b9fccee01669ceb9bb7b844056 Mon Sep 17 00:00:00 2001 From: Sharath Srinivasan Date: Sat, 8 Aug 2026 17:51:02 -0700 Subject: [PATCH 1/2] net/rds: reinitialize to_be_dropped on rds_send_xmit() restart The to_be_dropped list is declared once at the top of rds_send_xmit() but the function can loop via "goto restart" after each batch. The code currently relies on rds_send_remove_from_sock() having emptied the list entry by entry (via list_del_init()) at the end of the previous batch; nothing in rds_send_xmit() itself guarantees the list head is empty when a new batch starts. Re-initialize the list on every restart, and warn once if it is ever found non-empty there: entries left on the list at that point would keep their message reference, their RDS_MSG_ON_SOCK accounting and their pending RDS_RDMA_DROPPED notification, so a silent re-init would orphan them. This is hardening: no user-visible bug is known in the current code. This mirrors Oracle UEK commit "net/rds: rds_send_xmit should INIT_LIST_HEAD(&to_be_dropped) on restart". Signed-off-by: Gerd Rausch Signed-off-by: Sharath Srinivasan [achender: port to net-next (keep the existing LIST_HEAD declaration and add only the restart re-init); warn if the restart invariant is violated; update commit message] Assisted-by: Claude-Code:claude-fable-5 Signed-off-by: Allison Henderson Link: https://patch.msgid.link/20260809005103.82371-2-achender@kernel.org Reviewed-by: Simon Horman Signed-off-by: Paolo Abeni --- net/rds/send.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/net/rds/send.c b/net/rds/send.c index 309021e0cc9b..15a1b97f13e7 100644 --- a/net/rds/send.c +++ b/net/rds/send.c @@ -200,6 +200,14 @@ int rds_send_xmit(struct rds_conn_path *cp) restart: batch_count = 0; + /* The drop processing after over_batch relies on + * rds_send_remove_from_sock() emptying to_be_dropped entry by + * entry; warn if that post-condition ever stops holding, and + * re-initialize the list head. + */ + WARN_ON_ONCE(!list_empty(&to_be_dropped)); + INIT_LIST_HEAD(&to_be_dropped); + /* * sendmsg calls here after having queued its message on the send * queue. We only have one task feeding the connection at a time. If From ff8376b2458d9026a51c615075e2d77e79757f31 Mon Sep 17 00:00:00 2001 From: William Kucharski Date: Sat, 8 Aug 2026 17:51:03 -0700 Subject: [PATCH 2/2] net/rds: initialize i_conn_path in rds_inc_init() rds_inc_init() initializes every field of the embedded rds_incoming except i_conn_path, and incomings are not zero-allocated (IB carves them out of a slab cache). The field therefore holds stale garbage for incs created by rds_ib. The loopback transport is different: rds_loop_xmit() re-runs rds_inc_init() on the message's embedded inc after rds_send_queue_rm() has already stored the connection path in it, so there the field holds a live value rather than garbage, and a NULL store would discard it. Switch rds_loop_xmit() to rds_inc_path_init() with the connection's single path, which is exactly the value readers of the field reconstruct for a non-multipath transport. With loopback preserving the field, initialize it to NULL in rds_inc_init() so that any future reader trips over a clean NULL pointer instead of a stale one, and so the two init helpers (rds_inc_init/rds_inc_path_init) leave the structure in an equivalent, fully-initialized state. Hardening only; no reader dereferences i_conn_path for a non-multipath transport today. This mirrors Oracle UEK commit "rds: rds_inc_init() should initialize the inc->i_conn_path field". Signed-off-by: William Kucharski [achender: port to net-next; keep loopback's i_conn_path valid by switching rds_loop_xmit() to rds_inc_path_init(); update commit message] Assisted-by: Claude-Code:claude-fable-5 Signed-off-by: Allison Henderson Link: https://patch.msgid.link/20260809005103.82371-3-achender@kernel.org Reviewed-by: Simon Horman Signed-off-by: Paolo Abeni --- net/rds/loop.c | 6 +++++- net/rds/recv.c | 1 + 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/net/rds/loop.c b/net/rds/loop.c index ac9295a766b1..e6b0750bbeda 100644 --- a/net/rds/loop.c +++ b/net/rds/loop.c @@ -89,7 +89,11 @@ static int rds_loop_xmit(struct rds_connection *conn, struct rds_message *rm, BUG_ON(hdr_off || sg || off); - rds_inc_init(&rm->m_inc, conn, &conn->c_laddr); + /* rds_send_queue_rm() stored the connection path in this embedded + * inc; use the path init so the re-initialization keeps the field + * valid instead of discarding it. + */ + rds_inc_path_init(&rm->m_inc, &conn->c_path[0], &conn->c_laddr); /* For the embedded inc. Matching put is in loop_inc_free() */ rds_message_addref(rm); diff --git a/net/rds/recv.c b/net/rds/recv.c index cf3884d87931..f1513dfb2716 100644 --- a/net/rds/recv.c +++ b/net/rds/recv.c @@ -47,6 +47,7 @@ void rds_inc_init(struct rds_incoming *inc, struct rds_connection *conn, refcount_set(&inc->i_refcount, 1); INIT_LIST_HEAD(&inc->i_item); inc->i_conn = conn; + inc->i_conn_path = NULL; inc->i_saddr = *saddr; inc->i_usercopy.rdma_cookie = 0; inc->i_usercopy.rx_tstamp = ktime_set(0, 0);