From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3AF4546C84B; Sat, 12 Sep 2026 10:49:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789210149; cv=none; b=jr5WmEXI9VofqLh2ZlY1raUk7XoRdIJeaRmqiTm5cNMvzhOPLI47vaKwh62ix63hgOTERzn2jG73gE2yiFlOVqJaC5PqWeZ5NQj2G1Fo9i3BzCghN/k0Yd1uN7Q373uYNgV5fxKu6PcZOZIY74mXNQy/M6BU41w508n1w7ChZYo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789210149; c=relaxed/simple; bh=H/U1jia2Fk+lMQHigxX43fGzkWsU1nzyR0tOYLb3sus=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WaW1sElnHwOO9wheeyPNmpefFfDdhEd38btecLt4vhyQla/8cXhkmCjnPrcSH8d4G90HC3r14HZhLI6SBWK6raMl15KPIQlq3I0UDVQCDBqudpaFpyEirnAMloHRH+GM2cEoZRsKtuxIijQxYTc1zIhNArCMZj5fA5b0iPmXXrE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=X+vPqci7; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="X+vPqci7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BB1A01F000FF; Sat, 12 Sep 2026 10:49:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789210143; bh=fpOseAJfVwQl7dZEaADp3cXVMLyIbIqYHrLungBdKrc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=X+vPqci7vyIAaoA6rXUn+8bx4JKXfpM2kfSBXwIXzqeVXs8pt3WIqqj8eCXtmYdH5 6P0/isckRFG9S09BiwOLuyYdYLcOSquvA//q9uBlIlZAbemXlMsU24FDt4MZVkrd40 z+AtDxaCjTZOQIdNfdxQAvjxyw7oMsCUEKgrQ4uk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yehyeong Lee , Leon Romanovsky , Sasha Levin Subject: [PATCH 6.18 0923/1518] IB/isert: delay the final Login Response until the session is registered Date: Sat, 12 Sep 2026 08:51:32 +0200 Message-ID: <20260912065644.329833206@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065623.398859879@linuxfoundation.org> References: <20260912065623.398859879@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yehyeong Lee [ Upstream commit 464f5afa92d071a226f88424803b0fcf88093ede ] isert_put_login_tx() puts the final Login Response on the wire before __transport_register_session(), which iscsi_post_login_handler() reaches only after iscsi_target_do_login() returns. An initiator that issues a SCSI command as soon as it sees that response can have it executed against an se_session whose se_tpg is still NULL, and the ib-comp-wq worker oopses on the NULL dereference. Oops: general protection fault, probably for non-canonical address 0xdffffc000000000f: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000078-0x000000000000007f] CPU: 0 UID: 0 PID: 178 Comm: kworker/0:1H Not tainted 7.2.0-rc5-V2CTL-gf5098b6bae76 #10 PREEMPT(lazy) Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Workqueue: ib-comp-wq ib_cq_poll_work RIP: 0010:target_submit+0xbe/0x390 Code: fa 48 c1 ea 03 80 3c 02 00 0f 85 89 02 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b 64 24 18 49 8d 7c 24 78 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 5a 02 00 00 48 8d 7b 78 4d 8b 6c 24 78 48 b8 00 RSP: 0018:ffff8881058cfa78 EFLAGS: 00010206 RAX: dffffc0000000000 RBX: ffff88810c78c6f0 RCX: ffffffff964bb363 RDX: 000000000000000f RSI: 00000000fffffe00 RDI: 0000000000000078 RBP: 1ffff11020b19f52 R08: 0000000000000001 R09: ffffed1020b19f52 R10: 0000000000000003 R11: ffff88810596c000 R12: 0000000000000000 R13: ffff88810c61b000 R14: ffff88810c6a3400 R15: ffff88810c61b044 FS: 0000000000000000(0000) GS:ffff8881822b2000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1f1b83c000 CR3: 000000006fe72001 CR4: 0000000000770ef0 PKRU: 55555554 Call Trace: ? __pfx__raw_spin_lock_bh+0x10/0x10 ? __pfx_target_submit+0x10/0x10 ? mutex_lock+0x81/0xe0 ? __pfx_mutex_lock+0x10/0x10 ? iscsit_execute_cmd+0x650/0x850 iscsit_sequence_cmd+0x186/0x3d0 iscsit_process_scsi_cmd+0x87/0x300 isert_recv_done+0x1002/0x2390 ? __pfx_isert_recv_done+0x10/0x10 ? rxe_poll_cq+0x253/0x3d0 ? finish_task_switch.isra.0+0x1dc/0xa70 __ib_process_cq+0xe1/0x390 ib_cq_poll_work+0x46/0x150 process_one_work+0x633/0x1030 ? assign_work+0x11d/0x370 worker_thread+0x45b/0xd10 ? __pfx_worker_thread+0x10/0x10 ? __pfx_worker_thread+0x10/0x10 kthread+0x2c6/0x3b0 ? recalc_sigpending+0x15c/0x1e0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x36e/0x5a0 ? __pfx_ret_from_fork+0x10/0x10 ? __switch_to+0x572/0xdd0 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 Modules linked in: ---[ end trace 0000000000000000 ]--- Delay the final Login Response instead. isert_get_rx_pdu() runs from iscsi_target_rx_thread() after conn->rx_login_comp, completed by iscsi_post_login_handler() after __transport_register_session(); iscsi-TCP and cxgbit already take PDUs from that thread, isert alone does not. The buffers are still posted first, so the initiator's first command does not meet an empty receive queue and nothing depends on RNR flow control, and the header and payload live in isert_conn, not in the struct iscsi_login that iscsi_target_nego_release() frees first. Over rxe, 400 login cycles per run, the oops appeared in 10 of 20 unpatched runs and in none of 20 runs with this patch. An initiator that never waits is handled by the next patch. Not tested: iWARP, discovery sessions over iSER, and real HCAs. Fixes: b8d26b3be8b3 ("iser-target: Add iSCSI Extensions for RDMA (iSER) target driver") Signed-off-by: Yehyeong Lee Link: https://patch.msgid.link/20260731041212.1733364-1-yhlee@isslab.korea.ac.kr Signed-off-by: Leon Romanovsky Signed-off-by: Sasha Levin --- drivers/infiniband/ulp/isert/ib_isert.c | 20 ++++++++++++++++++-- drivers/infiniband/ulp/isert/ib_isert.h | 1 + 2 files changed, 19 insertions(+), 2 deletions(-) diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c index 1fcaf7df8b398..d0e3d1cf5b41b 100644 --- a/drivers/infiniband/ulp/isert/ib_isert.c +++ b/drivers/infiniband/ulp/isert/ib_isert.c @@ -59,6 +59,8 @@ static void isert_recv_done(struct ib_cq *cq, struct ib_wc *wc); static void isert_send_done(struct ib_cq *cq, struct ib_wc *wc); static void isert_login_recv_done(struct ib_cq *cq, struct ib_wc *wc); static void isert_login_send_done(struct ib_cq *cq, struct ib_wc *wc); +static void isert_unmap_tx_desc(struct iser_tx_desc *tx_desc, + struct ib_device *ib_dev); static int isert_sg_tablesize_set(const char *val, const struct kernel_param *kp) { @@ -498,6 +500,8 @@ isert_connect_release(struct isert_conn *isert_conn) if (isert_conn->qp) isert_destroy_qp(isert_conn); + isert_unmap_tx_desc(&isert_conn->login_tx_desc, device->ib_device); + if (isert_conn->login_desc) isert_free_login_buf(isert_conn); @@ -958,14 +962,17 @@ isert_put_login_tx(struct iscsit_conn *conn, struct iscsi_login *login, mutex_lock(&isert_conn->mutex); isert_conn->state = ISER_CONN_FULL_FEATURE; mutex_unlock(&isert_conn->mutex); - goto post_send; + + /* Sent from isert_get_rx_pdu() after registration. */ + isert_conn->login_rsp_pending = true; + return 0; } ret = isert_login_post_recv(isert_conn); if (ret) return ret; } -post_send: + ret = isert_login_post_send(isert_conn, tx_desc); if (ret) return ret; @@ -2625,8 +2632,17 @@ static void isert_free_conn(struct iscsit_conn *conn) static void isert_get_rx_pdu(struct iscsit_conn *conn) { + struct isert_conn *isert_conn = conn->context; struct completion comp; + /* The session is registered by now; see isert_put_login_tx(). */ + if (isert_conn->login_rsp_pending) { + isert_conn->login_rsp_pending = false; + if (isert_login_post_send(isert_conn, + &isert_conn->login_tx_desc)) + return; + } + init_completion(&comp); wait_for_completion_interruptible(&comp); diff --git a/drivers/infiniband/ulp/isert/ib_isert.h b/drivers/infiniband/ulp/isert/ib_isert.h index 0b2dfd6e7e270..0bac5aa66c802 100644 --- a/drivers/infiniband/ulp/isert/ib_isert.h +++ b/drivers/infiniband/ulp/isert/ib_isert.h @@ -178,6 +178,7 @@ struct isert_conn { struct completion login_comp; struct completion login_req_comp; struct iser_tx_desc login_tx_desc; + bool login_rsp_pending; struct rdma_cm_id *cm_id; struct ib_qp *qp; struct ib_cq *cq; -- 2.53.0