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GET /api/patches/1371796/?format=api
HTTP 200 OK
Allow: GET, PUT, PATCH, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "id": 1371796,
    "url": "http://patchwork.ozlabs.org/api/patches/1371796/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/netdev/patch/20200926165625.11660-1-manivannan.sadhasivam@linaro.org/",
    "project": {
        "id": 7,
        "url": "http://patchwork.ozlabs.org/api/projects/7/?format=api",
        "name": "Linux network development",
        "link_name": "netdev",
        "list_id": "netdev.vger.kernel.org",
        "list_email": "netdev@vger.kernel.org",
        "web_url": null,
        "scm_url": null,
        "webscm_url": null,
        "list_archive_url": "",
        "list_archive_url_format": "",
        "commit_url_format": ""
    },
    "msgid": "<20200926165625.11660-1-manivannan.sadhasivam@linaro.org>",
    "list_archive_url": null,
    "date": "2020-09-26T16:56:25",
    "name": "net: qrtr: ns: Protect radix_tree_deref_slot() using rcu read locks",
    "commit_ref": null,
    "pull_url": null,
    "state": "accepted",
    "archived": false,
    "hash": "c714a4c2210be53e3092fc97b9940b47e094ea8d",
    "submitter": {
        "id": 71790,
        "url": "http://patchwork.ozlabs.org/api/people/71790/?format=api",
        "name": "Manivannan Sadhasivam",
        "email": "manivannan.sadhasivam@linaro.org"
    },
    "delegate": {
        "id": 34,
        "url": "http://patchwork.ozlabs.org/api/users/34/?format=api",
        "username": "davem",
        "first_name": "David",
        "last_name": "Miller",
        "email": "davem@davemloft.net"
    },
    "mbox": "http://patchwork.ozlabs.org/project/netdev/patch/20200926165625.11660-1-manivannan.sadhasivam@linaro.org/mbox/",
    "series": [
        {
            "id": 204335,
            "url": "http://patchwork.ozlabs.org/api/series/204335/?format=api",
            "web_url": "http://patchwork.ozlabs.org/project/netdev/list/?series=204335",
            "date": "2020-09-26T16:56:25",
            "name": "net: qrtr: ns: Protect radix_tree_deref_slot() using rcu read locks",
            "version": 1,
            "mbox": "http://patchwork.ozlabs.org/series/204335/mbox/"
        }
    ],
    "comments": "http://patchwork.ozlabs.org/api/patches/1371796/comments/",
    "check": "pending",
    "checks": "http://patchwork.ozlabs.org/api/patches/1371796/checks/",
    "tags": {},
    "related": [],
    "headers": {
        "Return-Path": "<netdev-owner@vger.kernel.org>",
        "X-Original-To": "patchwork-incoming-netdev@ozlabs.org",
        "Delivered-To": "patchwork-incoming-netdev@ozlabs.org",
        "Authentication-Results": [
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        ],
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        ],
        "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed;\n        d=linaro.org; s=google;\n        h=from:to:cc:subject:date:message-id;\n        bh=SVaJEVx3uY1TIDW2WVtd8VWUc74/BP701w9CmWsP2ok=;\n        b=CxiwS6oP1IEB7r6bdBr1EaoR1GNhHMPSER8WzM0pd7a/qZU1XucYgI9FiVHsnwdaGY\n         9hHs3vswi2h8ER5CDxaKDT7aIXmw6dx6bVx5l/lDVwHUyX2hDcD/fkbvhOn1zeqMYvp7\n         iXI7DRSHufFp2SLp03tAYIiEp/X1/GrLcgw+opDyZqE4IsF46LPY1PvANrdKpgZRQ0Rm\n         mT9R7Mrh7bIjt8Y49ERHl7qrtsjoOAYDUC1eEw5bbHUKgQX0k0K+P1il+QqPB4Z6F/MG\n         4Qco9Rk9WT9mOtVzPHP2jbdq10F6wPXoe/MWUDGJts3nPKdWhK9eBVsQcrBsX+/xP1At\n         L3/w==",
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        "X-Gm-Message-State": "AOAM5321DL2Zm2WG48cRhc7obmxE71R8iYOtm17yX1pX4kGHhHlNDcgU\n        eo9Fqivr/qpxvUpP1yG2S97s",
        "X-Google-Smtp-Source": "\n ABdhPJzNC6LFuvvQ5gUUw3Dq9W9gpSzB7SSeCXmcxmo9cmtpNJPtro32GrVENIJbYn7rZ5aLySsRQQ==",
        "X-Received": "by 2002:a17:90a:2a88:: with SMTP id\n j8mr1192410pjd.35.1601139395744;\n        Sat, 26 Sep 2020 09:56:35 -0700 (PDT)",
        "From": "Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>",
        "To": "davem@davemloft.net, kuba@kernel.org",
        "Cc": "bjorn.andersson@linaro.org, netdev@vger.kernel.org,\n        linux-kernel@vger.kernel.org, sboyd@kernel.org,\n        Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>",
        "Subject": "[PATCH] net: qrtr: ns: Protect radix_tree_deref_slot() using rcu read\n locks",
        "Date": "Sat, 26 Sep 2020 22:26:25 +0530",
        "Message-Id": "<20200926165625.11660-1-manivannan.sadhasivam@linaro.org>",
        "X-Mailer": "git-send-email 2.17.1",
        "Precedence": "bulk",
        "List-ID": "<netdev.vger.kernel.org>",
        "X-Mailing-List": "netdev@vger.kernel.org"
    },
    "content": "The rcu read locks are needed to avoid potential race condition while\ndereferencing radix tree from multiple threads. The issue was identified\nby syzbot. Below is the crash report:\n\n=============================\nWARNING: suspicious RCU usage\n5.7.0-syzkaller #0 Not tainted\n-----------------------------\ninclude/linux/radix-tree.h:176 suspicious rcu_dereference_check() usage!\n\nother info that might help us debug this:\n\nrcu_scheduler_active = 2, debug_locks = 1\n2 locks held by kworker/u4:1/21:\n #0: ffff88821b097938 ((wq_completion)qrtr_ns_handler){+.+.}-{0:0}, at: spin_unlock_irq include/linux/spinlock.h:403 [inline]\n #0: ffff88821b097938 ((wq_completion)qrtr_ns_handler){+.+.}-{0:0}, at: process_one_work+0x6df/0xfd0 kernel/workqueue.c:2241\n #1: ffffc90000dd7d80 ((work_completion)(&qrtr_ns.work)){+.+.}-{0:0}, at: process_one_work+0x71e/0xfd0 kernel/workqueue.c:2243\n\nstack backtrace:\nCPU: 0 PID: 21 Comm: kworker/u4:1 Not tainted 5.7.0-syzkaller #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011\nWorkqueue: qrtr_ns_handler qrtr_ns_worker\nCall Trace:\n __dump_stack lib/dump_stack.c:77 [inline]\n dump_stack+0x1e9/0x30e lib/dump_stack.c:118\n radix_tree_deref_slot include/linux/radix-tree.h:176 [inline]\n ctrl_cmd_new_lookup net/qrtr/ns.c:558 [inline]\n qrtr_ns_worker+0x2aff/0x4500 net/qrtr/ns.c:674\n process_one_work+0x76e/0xfd0 kernel/workqueue.c:2268\n worker_thread+0xa7f/0x1450 kernel/workqueue.c:2414\n kthread+0x353/0x380 kernel/kthread.c:268\n\nFixes: 0c2204a4ad71 (\"net: qrtr: Migrate nameservice to kernel from userspace\")\nReported-and-tested-by: syzbot+0f84f6eed90503da72fc@syzkaller.appspotmail.com\nSigned-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>\n---\n net/qrtr/ns.c | 34 +++++++++++++++++++++++++---------\n 1 file changed, 25 insertions(+), 9 deletions(-)",
    "diff": "diff --git a/net/qrtr/ns.c b/net/qrtr/ns.c\nindex d8252fdab851..934999b56d60 100644\n--- a/net/qrtr/ns.c\n+++ b/net/qrtr/ns.c\n@@ -193,12 +193,13 @@ static int announce_servers(struct sockaddr_qrtr *sq)\n \tstruct qrtr_server *srv;\n \tstruct qrtr_node *node;\n \tvoid __rcu **slot;\n-\tint ret;\n+\tint ret = 0;\n \n \tnode = node_get(qrtr_ns.local_node);\n \tif (!node)\n \t\treturn 0;\n \n+\trcu_read_lock();\n \t/* Announce the list of servers registered in this node */\n \tradix_tree_for_each_slot(slot, &node->servers, &iter, 0) {\n \t\tsrv = radix_tree_deref_slot(slot);\n@@ -206,11 +207,14 @@ static int announce_servers(struct sockaddr_qrtr *sq)\n \t\tret = service_announce_new(sq, srv);\n \t\tif (ret < 0) {\n \t\t\tpr_err(\"failed to announce new service\\n\");\n-\t\t\treturn ret;\n+\t\t\tgoto err_out;\n \t\t}\n \t}\n \n-\treturn 0;\n+err_out:\n+\trcu_read_unlock();\n+\n+\treturn ret;\n }\n \n static struct qrtr_server *server_add(unsigned int service,\n@@ -335,7 +339,7 @@ static int ctrl_cmd_bye(struct sockaddr_qrtr *from)\n \tstruct qrtr_node *node;\n \tvoid __rcu **slot;\n \tstruct kvec iv;\n-\tint ret;\n+\tint ret = 0;\n \n \tiv.iov_base = &pkt;\n \tiv.iov_len = sizeof(pkt);\n@@ -344,11 +348,13 @@ static int ctrl_cmd_bye(struct sockaddr_qrtr *from)\n \tif (!node)\n \t\treturn 0;\n \n+\trcu_read_lock();\n \t/* Advertise removal of this client to all servers of remote node */\n \tradix_tree_for_each_slot(slot, &node->servers, &iter, 0) {\n \t\tsrv = radix_tree_deref_slot(slot);\n \t\tserver_del(node, srv->port);\n \t}\n+\trcu_read_unlock();\n \n \t/* Advertise the removal of this client to all local servers */\n \tlocal_node = node_get(qrtr_ns.local_node);\n@@ -359,6 +365,7 @@ static int ctrl_cmd_bye(struct sockaddr_qrtr *from)\n \tpkt.cmd = cpu_to_le32(QRTR_TYPE_BYE);\n \tpkt.client.node = cpu_to_le32(from->sq_node);\n \n+\trcu_read_lock();\n \tradix_tree_for_each_slot(slot, &local_node->servers, &iter, 0) {\n \t\tsrv = radix_tree_deref_slot(slot);\n \n@@ -372,11 +379,14 @@ static int ctrl_cmd_bye(struct sockaddr_qrtr *from)\n \t\tret = kernel_sendmsg(qrtr_ns.sock, &msg, &iv, 1, sizeof(pkt));\n \t\tif (ret < 0) {\n \t\t\tpr_err(\"failed to send bye cmd\\n\");\n-\t\t\treturn ret;\n+\t\t\tgoto err_out;\n \t\t}\n \t}\n \n-\treturn 0;\n+err_out:\n+\trcu_read_unlock();\n+\n+\treturn ret;\n }\n \n static int ctrl_cmd_del_client(struct sockaddr_qrtr *from,\n@@ -394,7 +404,7 @@ static int ctrl_cmd_del_client(struct sockaddr_qrtr *from,\n \tstruct list_head *li;\n \tvoid __rcu **slot;\n \tstruct kvec iv;\n-\tint ret;\n+\tint ret = 0;\n \n \tiv.iov_base = &pkt;\n \tiv.iov_len = sizeof(pkt);\n@@ -434,6 +444,7 @@ static int ctrl_cmd_del_client(struct sockaddr_qrtr *from,\n \tpkt.client.node = cpu_to_le32(node_id);\n \tpkt.client.port = cpu_to_le32(port);\n \n+\trcu_read_lock();\n \tradix_tree_for_each_slot(slot, &local_node->servers, &iter, 0) {\n \t\tsrv = radix_tree_deref_slot(slot);\n \n@@ -447,11 +458,14 @@ static int ctrl_cmd_del_client(struct sockaddr_qrtr *from,\n \t\tret = kernel_sendmsg(qrtr_ns.sock, &msg, &iv, 1, sizeof(pkt));\n \t\tif (ret < 0) {\n \t\t\tpr_err(\"failed to send del client cmd\\n\");\n-\t\t\treturn ret;\n+\t\t\tgoto err_out;\n \t\t}\n \t}\n \n-\treturn 0;\n+err_out:\n+\trcu_read_unlock();\n+\n+\treturn ret;\n }\n \n static int ctrl_cmd_new_server(struct sockaddr_qrtr *from,\n@@ -554,6 +568,7 @@ static int ctrl_cmd_new_lookup(struct sockaddr_qrtr *from,\n \tfilter.service = service;\n \tfilter.instance = instance;\n \n+\trcu_read_lock();\n \tradix_tree_for_each_slot(node_slot, &nodes, &node_iter, 0) {\n \t\tnode = radix_tree_deref_slot(node_slot);\n \n@@ -568,6 +583,7 @@ static int ctrl_cmd_new_lookup(struct sockaddr_qrtr *from,\n \t\t\tlookup_notify(from, srv, true);\n \t\t}\n \t}\n+\trcu_read_unlock();\n \n \t/* Empty notification, to indicate end of listing */\n \tlookup_notify(from, NULL, true);\n",
    "prefixes": []
}