{"id":807538,"url":"http://patchwork.ozlabs.org/api/1.0/patches/807538/?format=json","project":{"id":7,"url":"http://patchwork.ozlabs.org/api/1.0/projects/7/?format=json","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},"msgid":"<1504086545-7777-3-git-send-email-nikolay@cumulusnetworks.com>","date":"2017-08-30T09:48:58","name":"[net,2/9] sch_multiq: fix double free on init failure","commit_ref":null,"pull_url":null,"state":"accepted","archived":true,"hash":"1b776c8d739df432db4b957862ac2c2d86241cd9","submitter":{"id":66448,"url":"http://patchwork.ozlabs.org/api/1.0/people/66448/?format=json","name":"Nikolay Aleksandrov","email":"nikolay@cumulusnetworks.com"},"delegate":{"id":34,"url":"http://patchwork.ozlabs.org/api/1.0/users/34/?format=json","username":"davem","first_name":"David","last_name":"Miller","email":"davem@davemloft.net"},"mbox":"http://patchwork.ozlabs.org/project/netdev/patch/1504086545-7777-3-git-send-email-nikolay@cumulusnetworks.com/mbox/","series":[{"id":565,"url":"http://patchwork.ozlabs.org/api/1.0/series/565/?format=json","date":"2017-08-30T09:48:56","name":"net/sched: init failure fixes","version":1,"mbox":"http://patchwork.ozlabs.org/series/565/mbox/"}],"check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/807538/checks/","tags":{},"headers":{"Return-Path":"<netdev-owner@vger.kernel.org>","X-Original-To":"patchwork-incoming@ozlabs.org","Delivered-To":"patchwork-incoming@ozlabs.org","Authentication-Results":["ozlabs.org;\n\tspf=none (mailfrom) smtp.mailfrom=vger.kernel.org\n\t(client-ip=209.132.180.67; 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<nikolay@cumulusnetworks.com>","Subject":"[PATCH net 2/9] sch_multiq: fix double free on init failure","Date":"Wed, 30 Aug 2017 12:48:58 +0300","Message-Id":"<1504086545-7777-3-git-send-email-nikolay@cumulusnetworks.com>","X-Mailer":"git-send-email 2.1.4","In-Reply-To":"<1504086545-7777-1-git-send-email-nikolay@cumulusnetworks.com>","References":"<1504086545-7777-1-git-send-email-nikolay@cumulusnetworks.com>","Sender":"netdev-owner@vger.kernel.org","Precedence":"bulk","List-ID":"<netdev.vger.kernel.org>","X-Mailing-List":"netdev@vger.kernel.org"},"content":"The below commit added a call to ->destroy() on init failure, but multiq\nstill frees ->queues on error in init, but ->queues is also freed by\n->destroy() thus we get double free and corrupted memory.\n\nVery easy to reproduce (eth0 not multiqueue):\n$ tc qdisc add dev eth0 root multiq\nRTNETLINK answers: Operation not supported\n$ ip l add dumdum type dummy\n(crash)\n\nTrace log:\n[ 3929.467747] general protection fault: 0000 [#1] SMP\n[ 3929.468083] Modules linked in:\n[ 3929.468302] CPU: 3 PID: 967 Comm: ip Not tainted 4.13.0-rc6+ #56\n[ 3929.468625] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014\n[ 3929.469124] task: ffff88003716a700 task.stack: ffff88005872c000\n[ 3929.469449] RIP: 0010:__kmalloc_track_caller+0x117/0x1be\n[ 3929.469746] RSP: 0018:ffff88005872f6a0 EFLAGS: 00010246\n[ 3929.470042] RAX: 00000000000002de RBX: 0000000058a59000 RCX: 00000000000002df\n[ 3929.470406] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff821f7020\n[ 3929.470770] RBP: ffff88005872f6e8 R08: 000000000001f010 R09: 0000000000000000\n[ 3929.471133] R10: ffff88005872f730 R11: 0000000000008cdd R12: ff006d75646d7564\n[ 3929.471496] R13: 00000000014000c0 R14: ffff88005b403c00 R15: ffff88005b403c00\n[ 3929.471869] FS:  00007f0b70480740(0000) GS:ffff88005d980000(0000) knlGS:0000000000000000\n[ 3929.472286] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[ 3929.472677] CR2: 00007ffcee4f3000 CR3: 0000000059d45000 CR4: 00000000000406e0\n[ 3929.473209] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n[ 3929.474109] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\n[ 3929.474873] Call Trace:\n[ 3929.475337]  ? kstrdup_const+0x23/0x25\n[ 3929.475863]  kstrdup+0x2e/0x4b\n[ 3929.476338]  kstrdup_const+0x23/0x25\n[ 3929.478084]  __kernfs_new_node+0x28/0xbc\n[ 3929.478478]  kernfs_new_node+0x35/0x55\n[ 3929.478929]  kernfs_create_link+0x23/0x76\n[ 3929.479478]  sysfs_do_create_link_sd.isra.2+0x85/0xd7\n[ 3929.480096]  sysfs_create_link+0x33/0x35\n[ 3929.480649]  device_add+0x200/0x589\n[ 3929.481184]  netdev_register_kobject+0x7c/0x12f\n[ 3929.481711]  register_netdevice+0x373/0x471\n[ 3929.482174]  rtnl_newlink+0x614/0x729\n[ 3929.482610]  ? rtnl_newlink+0x17f/0x729\n[ 3929.483080]  rtnetlink_rcv_msg+0x188/0x197\n[ 3929.483533]  ? rcu_read_unlock+0x3e/0x5f\n[ 3929.483984]  ? rtnl_newlink+0x729/0x729\n[ 3929.484420]  netlink_rcv_skb+0x6c/0xce\n[ 3929.484858]  rtnetlink_rcv+0x23/0x2a\n[ 3929.485291]  netlink_unicast+0x103/0x181\n[ 3929.485735]  netlink_sendmsg+0x326/0x337\n[ 3929.486181]  sock_sendmsg_nosec+0x14/0x3f\n[ 3929.486614]  sock_sendmsg+0x29/0x2e\n[ 3929.486973]  ___sys_sendmsg+0x209/0x28b\n[ 3929.487340]  ? do_raw_spin_unlock+0xcd/0xf8\n[ 3929.487719]  ? _raw_spin_unlock+0x27/0x31\n[ 3929.488092]  ? __handle_mm_fault+0x651/0xdb1\n[ 3929.488471]  ? check_chain_key+0xb0/0xfd\n[ 3929.488847]  __sys_sendmsg+0x45/0x63\n[ 3929.489206]  ? __sys_sendmsg+0x45/0x63\n[ 3929.489576]  SyS_sendmsg+0x19/0x1b\n[ 3929.489901]  entry_SYSCALL_64_fastpath+0x23/0xc2\n[ 3929.490172] RIP: 0033:0x7f0b6fb93690\n[ 3929.490423] RSP: 002b:00007ffcee4ed588 EFLAGS: 00000246 ORIG_RAX: 000000000000002e\n[ 3929.490881] RAX: ffffffffffffffda RBX: ffffffff810d278c RCX: 00007f0b6fb93690\n[ 3929.491198] RDX: 0000000000000000 RSI: 00007ffcee4ed5d0 RDI: 0000000000000003\n[ 3929.491521] RBP: ffff88005872ff98 R08: 0000000000000001 R09: 0000000000000000\n[ 3929.491801] R10: 00007ffcee4ed350 R11: 0000000000000246 R12: 0000000000000002\n[ 3929.492075] R13: 000000000066f1a0 R14: 00007ffcee4f5680 R15: 0000000000000000\n[ 3929.492352]  ? trace_hardirqs_off_caller+0xa7/0xcf\n[ 3929.492590] Code: 8b 45 c0 48 8b 45 b8 74 17 48 8b 4d c8 83 ca ff 44\n89 ee 4c 89 f7 e8 83 ca ff ff 49 89 c4 eb 49 49 63 56 20 48 8d 48 01 4d\n8b 06 <49> 8b 1c 14 48 89 c2 4c 89 e0 65 49 0f c7 08 0f 94 c0 83 f0 01\n[ 3929.493335] RIP: __kmalloc_track_caller+0x117/0x1be RSP: ffff88005872f6a0\n\nFixes: 87b60cfacf9f (\"net_sched: fix error recovery at qdisc creation\")\nFixes: f07d1501292b (\"multiq: Further multiqueue cleanup\")\nSigned-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>\n---\n net/sched/sch_multiq.c | 7 +------\n 1 file changed, 1 insertion(+), 6 deletions(-)","diff":"diff --git a/net/sched/sch_multiq.c b/net/sched/sch_multiq.c\nindex f143b7bbaa0d..9c454f5d6c38 100644\n--- a/net/sched/sch_multiq.c\n+++ b/net/sched/sch_multiq.c\n@@ -257,12 +257,7 @@ static int multiq_init(struct Qdisc *sch, struct nlattr *opt)\n \tfor (i = 0; i < q->max_bands; i++)\n \t\tq->queues[i] = &noop_qdisc;\n \n-\terr = multiq_tune(sch, opt);\n-\n-\tif (err)\n-\t\tkfree(q->queues);\n-\n-\treturn err;\n+\treturn multiq_tune(sch, opt);\n }\n \n static int multiq_dump(struct Qdisc *sch, struct sk_buff *skb)\n","prefixes":["net","2/9"]}