linux.git/net/sched, branch v4.13 Linux kernel source tree sch_tbf: fix two null pointer dereferences on init failure 2017-08-30T22:26:12+00:00 Nikolay Aleksandrov nikolay@cumulusnetworks.com 2017-08-30T09:49:05+00:00 c2d6511e6a4f1f3673d711569c00c3849549e9b0 sch_tbf calls qdisc_watchdog_cancel() in both its ->reset and ->destroy callbacks but it may fail before the timer is initialized due to missing options (either not supplied by user-space or set as a default qdisc), also q->qdisc is used by ->reset and ->destroy so we need it initialized. Reproduce: $ sysctl net.core.default_qdisc=tbf $ ip l set ethX up Crash log: [ 959.160172] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 [ 959.160323] IP: qdisc_reset+0xa/0x5c [ 959.160400] PGD 59cdb067 [ 959.160401] P4D 59cdb067 [ 959.160466] PUD 59ccb067 [ 959.160532] PMD 0 [ 959.160597] [ 959.160706] Oops: 0000 [#1] SMP [ 959.160778] Modules linked in: sch_tbf sch_sfb sch_prio sch_netem [ 959.160891] CPU: 2 PID: 1562 Comm: ip Not tainted 4.13.0-rc6+ #62 [ 959.160998] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014 [ 959.161157] task: ffff880059c9a700 task.stack: ffff8800376d0000 [ 959.161263] RIP: 0010:qdisc_reset+0xa/0x5c [ 959.161347] RSP: 0018:ffff8800376d3610 EFLAGS: 00010286 [ 959.161531] RAX: ffffffffa001b1dd RBX: ffff8800373a2800 RCX: 0000000000000000 [ 959.161733] RDX: ffffffff8215f160 RSI: ffffffff8215f160 RDI: 0000000000000000 [ 959.161939] RBP: ffff8800376d3618 R08: 00000000014080c0 R09: 00000000ffffffff [ 959.162141] R10: ffff8800376d3578 R11: 0000000000000020 R12: ffffffffa001d2c0 [ 959.162343] R13: ffff880037538000 R14: 00000000ffffffff R15: 0000000000000001 [ 959.162546] FS: 00007fcc5126b740(0000) GS:ffff88005d900000(0000) knlGS:0000000000000000 [ 959.162844] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 959.163030] CR2: 0000000000000018 CR3: 000000005abc4000 CR4: 00000000000406e0 [ 959.163233] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 959.163436] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 959.163638] Call Trace: [ 959.163788] tbf_reset+0x19/0x64 [sch_tbf] [ 959.163957] qdisc_destroy+0x8b/0xe5 [ 959.164119] qdisc_create_dflt+0x86/0x94 [ 959.164284] ? dev_activate+0x129/0x129 [ 959.164449] attach_one_default_qdisc+0x36/0x63 [ 959.164623] netdev_for_each_tx_queue+0x3d/0x48 [ 959.164795] dev_activate+0x4b/0x129 [ 959.164957] __dev_open+0xe7/0x104 [ 959.165118] __dev_change_flags+0xc6/0x15c [ 959.165287] dev_change_flags+0x25/0x59 [ 959.165451] do_setlink+0x30c/0xb3f [ 959.165613] ? check_chain_key+0xb0/0xfd [ 959.165782] rtnl_newlink+0x3a4/0x729 [ 959.165947] ? rtnl_newlink+0x117/0x729 [ 959.166121] ? ns_capable_common+0xd/0xb1 [ 959.166288] ? ns_capable+0x13/0x15 [ 959.166450] rtnetlink_rcv_msg+0x188/0x197 [ 959.166617] ? rcu_read_unlock+0x3e/0x5f [ 959.166783] ? rtnl_newlink+0x729/0x729 [ 959.166948] netlink_rcv_skb+0x6c/0xce [ 959.167113] rtnetlink_rcv+0x23/0x2a [ 959.167273] netlink_unicast+0x103/0x181 [ 959.167439] netlink_sendmsg+0x326/0x337 [ 959.167607] sock_sendmsg_nosec+0x14/0x3f [ 959.167772] sock_sendmsg+0x29/0x2e [ 959.167932] ___sys_sendmsg+0x209/0x28b [ 959.168098] ? do_raw_spin_unlock+0xcd/0xf8 [ 959.168267] ? _raw_spin_unlock+0x27/0x31 [ 959.168432] ? __handle_mm_fault+0x651/0xdb1 [ 959.168602] ? check_chain_key+0xb0/0xfd [ 959.168773] __sys_sendmsg+0x45/0x63 [ 959.168934] ? __sys_sendmsg+0x45/0x63 [ 959.169100] SyS_sendmsg+0x19/0x1b [ 959.169260] entry_SYSCALL_64_fastpath+0x23/0xc2 [ 959.169432] RIP: 0033:0x7fcc5097e690 [ 959.169592] RSP: 002b:00007ffd0d5c7b48 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 959.169887] RAX: ffffffffffffffda RBX: ffffffff810d278c RCX: 00007fcc5097e690 [ 959.170089] RDX: 0000000000000000 RSI: 00007ffd0d5c7b90 RDI: 0000000000000003 [ 959.170292] RBP: ffff8800376d3f98 R08: 0000000000000001 R09: 0000000000000003 [ 959.170494] R10: 00007ffd0d5c7910 R11: 0000000000000246 R12: 0000000000000006 [ 959.170697] R13: 000000000066f1a0 R14: 00007ffd0d5cfc40 R15: 0000000000000000 [ 959.170900] ? trace_hardirqs_off_caller+0xa7/0xcf [ 959.171076] Code: 00 41 c7 84 24 14 01 00 00 00 00 00 00 41 c7 84 24 98 00 00 00 00 00 00 00 41 5c 41 5d 41 5e 5d c3 66 66 66 66 90 55 48 89 e5 53 <48> 8b 47 18 48 89 fb 48 8b 40 48 48 85 c0 74 02 ff d0 48 8b bb [ 959.171637] RIP: qdisc_reset+0xa/0x5c RSP: ffff8800376d3610 [ 959.171821] CR2: 0000000000000018 Fixes: 87b60cfacf9f ("net_sched: fix error recovery at qdisc creation") Fixes: 0fbbeb1ba43b ("[PKT_SCHED]: Fix missing qdisc_destroy() in qdisc_create_dflt()") Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
sch_tbf calls qdisc_watchdog_cancel() in both its ->reset and ->destroy
callbacks but it may fail before the timer is initialized due to missing
options (either not supplied by user-space or set as a default qdisc),
also q->qdisc is used by ->reset and ->destroy so we need it initialized.

Reproduce:
$ sysctl net.core.default_qdisc=tbf
$ ip l set ethX up

Crash log:
[  959.160172] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
[  959.160323] IP: qdisc_reset+0xa/0x5c
[  959.160400] PGD 59cdb067
[  959.160401] P4D 59cdb067
[  959.160466] PUD 59ccb067
[  959.160532] PMD 0
[  959.160597]
[  959.160706] Oops: 0000 [#1] SMP
[  959.160778] Modules linked in: sch_tbf sch_sfb sch_prio sch_netem
[  959.160891] CPU: 2 PID: 1562 Comm: ip Not tainted 4.13.0-rc6+ #62
[  959.160998] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
[  959.161157] task: ffff880059c9a700 task.stack: ffff8800376d0000
[  959.161263] RIP: 0010:qdisc_reset+0xa/0x5c
[  959.161347] RSP: 0018:ffff8800376d3610 EFLAGS: 00010286
[  959.161531] RAX: ffffffffa001b1dd RBX: ffff8800373a2800 RCX: 0000000000000000
[  959.161733] RDX: ffffffff8215f160 RSI: ffffffff8215f160 RDI: 0000000000000000
[  959.161939] RBP: ffff8800376d3618 R08: 00000000014080c0 R09: 00000000ffffffff
[  959.162141] R10: ffff8800376d3578 R11: 0000000000000020 R12: ffffffffa001d2c0
[  959.162343] R13: ffff880037538000 R14: 00000000ffffffff R15: 0000000000000001
[  959.162546] FS:  00007fcc5126b740(0000) GS:ffff88005d900000(0000) knlGS:0000000000000000
[  959.162844] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  959.163030] CR2: 0000000000000018 CR3: 000000005abc4000 CR4: 00000000000406e0
[  959.163233] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  959.163436] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  959.163638] Call Trace:
[  959.163788]  tbf_reset+0x19/0x64 [sch_tbf]
[  959.163957]  qdisc_destroy+0x8b/0xe5
[  959.164119]  qdisc_create_dflt+0x86/0x94
[  959.164284]  ? dev_activate+0x129/0x129
[  959.164449]  attach_one_default_qdisc+0x36/0x63
[  959.164623]  netdev_for_each_tx_queue+0x3d/0x48
[  959.164795]  dev_activate+0x4b/0x129
[  959.164957]  __dev_open+0xe7/0x104
[  959.165118]  __dev_change_flags+0xc6/0x15c
[  959.165287]  dev_change_flags+0x25/0x59
[  959.165451]  do_setlink+0x30c/0xb3f
[  959.165613]  ? check_chain_key+0xb0/0xfd
[  959.165782]  rtnl_newlink+0x3a4/0x729
[  959.165947]  ? rtnl_newlink+0x117/0x729
[  959.166121]  ? ns_capable_common+0xd/0xb1
[  959.166288]  ? ns_capable+0x13/0x15
[  959.166450]  rtnetlink_rcv_msg+0x188/0x197
[  959.166617]  ? rcu_read_unlock+0x3e/0x5f
[  959.166783]  ? rtnl_newlink+0x729/0x729
[  959.166948]  netlink_rcv_skb+0x6c/0xce
[  959.167113]  rtnetlink_rcv+0x23/0x2a
[  959.167273]  netlink_unicast+0x103/0x181
[  959.167439]  netlink_sendmsg+0x326/0x337
[  959.167607]  sock_sendmsg_nosec+0x14/0x3f
[  959.167772]  sock_sendmsg+0x29/0x2e
[  959.167932]  ___sys_sendmsg+0x209/0x28b
[  959.168098]  ? do_raw_spin_unlock+0xcd/0xf8
[  959.168267]  ? _raw_spin_unlock+0x27/0x31
[  959.168432]  ? __handle_mm_fault+0x651/0xdb1
[  959.168602]  ? check_chain_key+0xb0/0xfd
[  959.168773]  __sys_sendmsg+0x45/0x63
[  959.168934]  ? __sys_sendmsg+0x45/0x63
[  959.169100]  SyS_sendmsg+0x19/0x1b
[  959.169260]  entry_SYSCALL_64_fastpath+0x23/0xc2
[  959.169432] RIP: 0033:0x7fcc5097e690
[  959.169592] RSP: 002b:00007ffd0d5c7b48 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[  959.169887] RAX: ffffffffffffffda RBX: ffffffff810d278c RCX: 00007fcc5097e690
[  959.170089] RDX: 0000000000000000 RSI: 00007ffd0d5c7b90 RDI: 0000000000000003
[  959.170292] RBP: ffff8800376d3f98 R08: 0000000000000001 R09: 0000000000000003
[  959.170494] R10: 00007ffd0d5c7910 R11: 0000000000000246 R12: 0000000000000006
[  959.170697] R13: 000000000066f1a0 R14: 00007ffd0d5cfc40 R15: 0000000000000000
[  959.170900]  ? trace_hardirqs_off_caller+0xa7/0xcf
[  959.171076] Code: 00 41 c7 84 24 14 01 00 00 00 00 00 00 41 c7 84 24
98 00 00 00 00 00 00 00 41 5c 41 5d 41 5e 5d c3 66 66 66 66 90 55 48 89
e5 53 <48> 8b 47 18 48 89 fb 48 8b 40 48 48 85 c0 74 02 ff d0 48 8b bb
[  959.171637] RIP: qdisc_reset+0xa/0x5c RSP: ffff8800376d3610
[  959.171821] CR2: 0000000000000018

Fixes: 87b60cfacf9f ("net_sched: fix error recovery at qdisc creation")
Fixes: 0fbbeb1ba43b ("[PKT_SCHED]: Fix missing qdisc_destroy() in qdisc_create_dflt()")
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sch_sfq: fix null pointer dereference on init failure 2017-08-30T22:26:12+00:00 Nikolay Aleksandrov nikolay@cumulusnetworks.com 2017-08-30T09:49:04+00:00 e232657661242cc8a169595160847b3e66aa7056 Currently only a memory allocation failure can lead to this, so let's initialize the timer first. Fixes: 6529eaba33f0 ("net: sched: introduce tcf block infractructure") Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
Currently only a memory allocation failure can lead to this, so let's
initialize the timer first.

Fixes: 6529eaba33f0 ("net: sched: introduce tcf block infractructure")
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sch_netem: avoid null pointer deref on init failure 2017-08-30T22:26:11+00:00 Nikolay Aleksandrov nikolay@cumulusnetworks.com 2017-08-30T09:49:03+00:00 634576a1844dba15bc5e6fc61d72f37e13a21615 netem can fail in ->init due to missing options (either not supplied by user-space or used as a default qdisc) causing a timer->base null pointer deref in its ->destroy() and ->reset() callbacks. Reproduce: $ sysctl net.core.default_qdisc=netem $ ip l set ethX up Crash log: [ 1814.846943] BUG: unable to handle kernel NULL pointer dereference at (null) [ 1814.847181] IP: hrtimer_active+0x17/0x8a [ 1814.847270] PGD 59c34067 [ 1814.847271] P4D 59c34067 [ 1814.847337] PUD 37374067 [ 1814.847403] PMD 0 [ 1814.847468] [ 1814.847582] Oops: 0000 [#1] SMP [ 1814.847655] Modules linked in: sch_netem(O) sch_fq_codel(O) [ 1814.847761] CPU: 3 PID: 1573 Comm: ip Tainted: G O 4.13.0-rc6+ #62 [ 1814.847884] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014 [ 1814.848043] task: ffff88003723a700 task.stack: ffff88005adc8000 [ 1814.848235] RIP: 0010:hrtimer_active+0x17/0x8a [ 1814.848407] RSP: 0018:ffff88005adcb590 EFLAGS: 00010246 [ 1814.848590] RAX: 0000000000000000 RBX: ffff880058e359d8 RCX: 0000000000000000 [ 1814.848793] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff880058e359d8 [ 1814.848998] RBP: ffff88005adcb5b0 R08: 00000000014080c0 R09: 00000000ffffffff [ 1814.849204] R10: ffff88005adcb660 R11: 0000000000000020 R12: 0000000000000000 [ 1814.849410] R13: ffff880058e359d8 R14: 00000000ffffffff R15: 0000000000000001 [ 1814.849616] FS: 00007f733bbca740(0000) GS:ffff88005d980000(0000) knlGS:0000000000000000 [ 1814.849919] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1814.850107] CR2: 0000000000000000 CR3: 0000000059f0d000 CR4: 00000000000406e0 [ 1814.850313] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1814.850518] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 1814.850723] Call Trace: [ 1814.850875] hrtimer_try_to_cancel+0x1a/0x93 [ 1814.851047] hrtimer_cancel+0x15/0x20 [ 1814.851211] qdisc_watchdog_cancel+0x12/0x14 [ 1814.851383] netem_reset+0xe6/0xed [sch_netem] [ 1814.851561] qdisc_destroy+0x8b/0xe5 [ 1814.851723] qdisc_create_dflt+0x86/0x94 [ 1814.851890] ? dev_activate+0x129/0x129 [ 1814.852057] attach_one_default_qdisc+0x36/0x63 [ 1814.852232] netdev_for_each_tx_queue+0x3d/0x48 [ 1814.852406] dev_activate+0x4b/0x129 [ 1814.852569] __dev_open+0xe7/0x104 [ 1814.852730] __dev_change_flags+0xc6/0x15c [ 1814.852899] dev_change_flags+0x25/0x59 [ 1814.853064] do_setlink+0x30c/0xb3f [ 1814.853228] ? check_chain_key+0xb0/0xfd [ 1814.853396] ? check_chain_key+0xb0/0xfd [ 1814.853565] rtnl_newlink+0x3a4/0x729 [ 1814.853728] ? rtnl_newlink+0x117/0x729 [ 1814.853905] ? ns_capable_common+0xd/0xb1 [ 1814.854072] ? ns_capable+0x13/0x15 [ 1814.854234] rtnetlink_rcv_msg+0x188/0x197 [ 1814.854404] ? rcu_read_unlock+0x3e/0x5f [ 1814.854572] ? rtnl_newlink+0x729/0x729 [ 1814.854737] netlink_rcv_skb+0x6c/0xce [ 1814.854902] rtnetlink_rcv+0x23/0x2a [ 1814.855064] netlink_unicast+0x103/0x181 [ 1814.855230] netlink_sendmsg+0x326/0x337 [ 1814.855398] sock_sendmsg_nosec+0x14/0x3f [ 1814.855584] sock_sendmsg+0x29/0x2e [ 1814.855747] ___sys_sendmsg+0x209/0x28b [ 1814.855912] ? do_raw_spin_unlock+0xcd/0xf8 [ 1814.856082] ? _raw_spin_unlock+0x27/0x31 [ 1814.856251] ? __handle_mm_fault+0x651/0xdb1 [ 1814.856421] ? check_chain_key+0xb0/0xfd [ 1814.856592] __sys_sendmsg+0x45/0x63 [ 1814.856755] ? __sys_sendmsg+0x45/0x63 [ 1814.856923] SyS_sendmsg+0x19/0x1b [ 1814.857083] entry_SYSCALL_64_fastpath+0x23/0xc2 [ 1814.857256] RIP: 0033:0x7f733b2dd690 [ 1814.857419] RSP: 002b:00007ffe1d3387d8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 1814.858238] RAX: ffffffffffffffda RBX: ffffffff810d278c RCX: 00007f733b2dd690 [ 1814.858445] RDX: 0000000000000000 RSI: 00007ffe1d338820 RDI: 0000000000000003 [ 1814.858651] RBP: ffff88005adcbf98 R08: 0000000000000001 R09: 0000000000000003 [ 1814.858856] R10: 00007ffe1d3385a0 R11: 0000000000000246 R12: 0000000000000002 [ 1814.859060] R13: 000000000066f1a0 R14: 00007ffe1d3408d0 R15: 0000000000000000 [ 1814.859267] ? trace_hardirqs_off_caller+0xa7/0xcf [ 1814.859446] Code: 10 55 48 89 c7 48 89 e5 e8 45 a1 fb ff 31 c0 5d c3 31 c0 c3 66 66 66 66 90 55 48 89 e5 41 56 41 55 41 54 53 49 89 fd 49 8b 45 30 <4c> 8b 20 41 8b 5c 24 38 31 c9 31 d2 48 c7 c7 50 8e 1d 82 41 89 [ 1814.860022] RIP: hrtimer_active+0x17/0x8a RSP: ffff88005adcb590 [ 1814.860214] CR2: 0000000000000000 Fixes: 87b60cfacf9f ("net_sched: fix error recovery at qdisc creation") Fixes: 0fbbeb1ba43b ("[PKT_SCHED]: Fix missing qdisc_destroy() in qdisc_create_dflt()") Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
netem can fail in ->init due to missing options (either not supplied by
user-space or used as a default qdisc) causing a timer->base null
pointer deref in its ->destroy() and ->reset() callbacks.

Reproduce:
$ sysctl net.core.default_qdisc=netem
$ ip l set ethX up

Crash log:
[ 1814.846943] BUG: unable to handle kernel NULL pointer dereference at (null)
[ 1814.847181] IP: hrtimer_active+0x17/0x8a
[ 1814.847270] PGD 59c34067
[ 1814.847271] P4D 59c34067
[ 1814.847337] PUD 37374067
[ 1814.847403] PMD 0
[ 1814.847468]
[ 1814.847582] Oops: 0000 [#1] SMP
[ 1814.847655] Modules linked in: sch_netem(O) sch_fq_codel(O)
[ 1814.847761] CPU: 3 PID: 1573 Comm: ip Tainted: G           O 4.13.0-rc6+ #62
[ 1814.847884] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
[ 1814.848043] task: ffff88003723a700 task.stack: ffff88005adc8000
[ 1814.848235] RIP: 0010:hrtimer_active+0x17/0x8a
[ 1814.848407] RSP: 0018:ffff88005adcb590 EFLAGS: 00010246
[ 1814.848590] RAX: 0000000000000000 RBX: ffff880058e359d8 RCX: 0000000000000000
[ 1814.848793] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff880058e359d8
[ 1814.848998] RBP: ffff88005adcb5b0 R08: 00000000014080c0 R09: 00000000ffffffff
[ 1814.849204] R10: ffff88005adcb660 R11: 0000000000000020 R12: 0000000000000000
[ 1814.849410] R13: ffff880058e359d8 R14: 00000000ffffffff R15: 0000000000000001
[ 1814.849616] FS:  00007f733bbca740(0000) GS:ffff88005d980000(0000) knlGS:0000000000000000
[ 1814.849919] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1814.850107] CR2: 0000000000000000 CR3: 0000000059f0d000 CR4: 00000000000406e0
[ 1814.850313] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1814.850518] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 1814.850723] Call Trace:
[ 1814.850875]  hrtimer_try_to_cancel+0x1a/0x93
[ 1814.851047]  hrtimer_cancel+0x15/0x20
[ 1814.851211]  qdisc_watchdog_cancel+0x12/0x14
[ 1814.851383]  netem_reset+0xe6/0xed [sch_netem]
[ 1814.851561]  qdisc_destroy+0x8b/0xe5
[ 1814.851723]  qdisc_create_dflt+0x86/0x94
[ 1814.851890]  ? dev_activate+0x129/0x129
[ 1814.852057]  attach_one_default_qdisc+0x36/0x63
[ 1814.852232]  netdev_for_each_tx_queue+0x3d/0x48
[ 1814.852406]  dev_activate+0x4b/0x129
[ 1814.852569]  __dev_open+0xe7/0x104
[ 1814.852730]  __dev_change_flags+0xc6/0x15c
[ 1814.852899]  dev_change_flags+0x25/0x59
[ 1814.853064]  do_setlink+0x30c/0xb3f
[ 1814.853228]  ? check_chain_key+0xb0/0xfd
[ 1814.853396]  ? check_chain_key+0xb0/0xfd
[ 1814.853565]  rtnl_newlink+0x3a4/0x729
[ 1814.853728]  ? rtnl_newlink+0x117/0x729
[ 1814.853905]  ? ns_capable_common+0xd/0xb1
[ 1814.854072]  ? ns_capable+0x13/0x15
[ 1814.854234]  rtnetlink_rcv_msg+0x188/0x197
[ 1814.854404]  ? rcu_read_unlock+0x3e/0x5f
[ 1814.854572]  ? rtnl_newlink+0x729/0x729
[ 1814.854737]  netlink_rcv_skb+0x6c/0xce
[ 1814.854902]  rtnetlink_rcv+0x23/0x2a
[ 1814.855064]  netlink_unicast+0x103/0x181
[ 1814.855230]  netlink_sendmsg+0x326/0x337
[ 1814.855398]  sock_sendmsg_nosec+0x14/0x3f
[ 1814.855584]  sock_sendmsg+0x29/0x2e
[ 1814.855747]  ___sys_sendmsg+0x209/0x28b
[ 1814.855912]  ? do_raw_spin_unlock+0xcd/0xf8
[ 1814.856082]  ? _raw_spin_unlock+0x27/0x31
[ 1814.856251]  ? __handle_mm_fault+0x651/0xdb1
[ 1814.856421]  ? check_chain_key+0xb0/0xfd
[ 1814.856592]  __sys_sendmsg+0x45/0x63
[ 1814.856755]  ? __sys_sendmsg+0x45/0x63
[ 1814.856923]  SyS_sendmsg+0x19/0x1b
[ 1814.857083]  entry_SYSCALL_64_fastpath+0x23/0xc2
[ 1814.857256] RIP: 0033:0x7f733b2dd690
[ 1814.857419] RSP: 002b:00007ffe1d3387d8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[ 1814.858238] RAX: ffffffffffffffda RBX: ffffffff810d278c RCX: 00007f733b2dd690
[ 1814.858445] RDX: 0000000000000000 RSI: 00007ffe1d338820 RDI: 0000000000000003
[ 1814.858651] RBP: ffff88005adcbf98 R08: 0000000000000001 R09: 0000000000000003
[ 1814.858856] R10: 00007ffe1d3385a0 R11: 0000000000000246 R12: 0000000000000002
[ 1814.859060] R13: 000000000066f1a0 R14: 00007ffe1d3408d0 R15: 0000000000000000
[ 1814.859267]  ? trace_hardirqs_off_caller+0xa7/0xcf
[ 1814.859446] Code: 10 55 48 89 c7 48 89 e5 e8 45 a1 fb ff 31 c0 5d c3
31 c0 c3 66 66 66 66 90 55 48 89 e5 41 56 41 55 41 54 53 49 89 fd 49 8b
45 30 <4c> 8b 20 41 8b 5c 24 38 31 c9 31 d2 48 c7 c7 50 8e 1d 82 41 89
[ 1814.860022] RIP: hrtimer_active+0x17/0x8a RSP: ffff88005adcb590
[ 1814.860214] CR2: 0000000000000000

Fixes: 87b60cfacf9f ("net_sched: fix error recovery at qdisc creation")
Fixes: 0fbbeb1ba43b ("[PKT_SCHED]: Fix missing qdisc_destroy() in qdisc_create_dflt()")
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sch_fq_codel: avoid double free on init failure 2017-08-30T22:26:11+00:00 Nikolay Aleksandrov nikolay@cumulusnetworks.com 2017-08-30T09:49:02+00:00 30c31d746d0eb458ae327f522bc8e4c44cbea0f0 It is very unlikely to happen but the backlogs memory allocation could fail and will free q->flows, but then ->destroy() will free q->flows too. For correctness remove the first free and let ->destroy clean up. Fixes: 87b60cfacf9f ("net_sched: fix error recovery at qdisc creation") Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
It is very unlikely to happen but the backlogs memory allocation
could fail and will free q->flows, but then ->destroy() will free
q->flows too. For correctness remove the first free and let ->destroy
clean up.

Fixes: 87b60cfacf9f ("net_sched: fix error recovery at qdisc creation")
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sch_cbq: fix null pointer dereferences on init failure 2017-08-30T22:26:11+00:00 Nikolay Aleksandrov nikolay@cumulusnetworks.com 2017-08-30T09:49:01+00:00 3501d059921246ff617b43e86250a719c140bd97 CBQ can fail on ->init by wrong nl attributes or simply for missing any, f.e. if it's set as a default qdisc then TCA_OPTIONS (opt) will be NULL when it is activated. The first thing init does is parse opt but it will dereference a null pointer if used as a default qdisc, also since init failure at default qdisc invokes ->reset() which cancels all timers then we'll also dereference two more null pointers (timer->base) as they were never initialized. To reproduce: $ sysctl net.core.default_qdisc=cbq $ ip l set ethX up Crash log of the first null ptr deref: [44727.907454] BUG: unable to handle kernel NULL pointer dereference at (null) [44727.907600] IP: cbq_init+0x27/0x205 [44727.907676] PGD 59ff4067 [44727.907677] P4D 59ff4067 [44727.907742] PUD 59c70067 [44727.907807] PMD 0 [44727.907873] [44727.907982] Oops: 0000 [#1] SMP [44727.908054] Modules linked in: [44727.908126] CPU: 1 PID: 21312 Comm: ip Not tainted 4.13.0-rc6+ #60 [44727.908235] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014 [44727.908477] task: ffff88005ad42700 task.stack: ffff880037214000 [44727.908672] RIP: 0010:cbq_init+0x27/0x205 [44727.908838] RSP: 0018:ffff8800372175f0 EFLAGS: 00010286 [44727.909018] RAX: ffffffff816c3852 RBX: ffff880058c53800 RCX: 0000000000000000 [44727.909222] RDX: 0000000000000004 RSI: 0000000000000000 RDI: ffff8800372175f8 [44727.909427] RBP: ffff880037217650 R08: ffffffff81b0f380 R09: 0000000000000000 [44727.909631] R10: ffff880037217660 R11: 0000000000000020 R12: ffffffff822a44c0 [44727.909835] R13: ffff880058b92000 R14: 00000000ffffffff R15: 0000000000000001 [44727.910040] FS: 00007ff8bc583740(0000) GS:ffff88005d880000(0000) knlGS:0000000000000000 [44727.910339] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [44727.910525] CR2: 0000000000000000 CR3: 00000000371e5000 CR4: 00000000000406e0 [44727.910731] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [44727.910936] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [44727.911141] Call Trace: [44727.911291] ? lockdep_init_map+0xb6/0x1ba [44727.911461] ? qdisc_alloc+0x14e/0x187 [44727.911626] qdisc_create_dflt+0x7a/0x94 [44727.911794] ? dev_activate+0x129/0x129 [44727.911959] attach_one_default_qdisc+0x36/0x63 [44727.912132] netdev_for_each_tx_queue+0x3d/0x48 [44727.912305] dev_activate+0x4b/0x129 [44727.912468] __dev_open+0xe7/0x104 [44727.912631] __dev_change_flags+0xc6/0x15c [44727.912799] dev_change_flags+0x25/0x59 [44727.912966] do_setlink+0x30c/0xb3f [44727.913129] ? check_chain_key+0xb0/0xfd [44727.913294] ? check_chain_key+0xb0/0xfd [44727.913463] rtnl_newlink+0x3a4/0x729 [44727.913626] ? rtnl_newlink+0x117/0x729 [44727.913801] ? ns_capable_common+0xd/0xb1 [44727.913968] ? ns_capable+0x13/0x15 [44727.914131] rtnetlink_rcv_msg+0x188/0x197 [44727.914300] ? rcu_read_unlock+0x3e/0x5f [44727.914465] ? rtnl_newlink+0x729/0x729 [44727.914630] netlink_rcv_skb+0x6c/0xce [44727.914796] rtnetlink_rcv+0x23/0x2a [44727.914956] netlink_unicast+0x103/0x181 [44727.915122] netlink_sendmsg+0x326/0x337 [44727.915291] sock_sendmsg_nosec+0x14/0x3f [44727.915459] sock_sendmsg+0x29/0x2e [44727.915619] ___sys_sendmsg+0x209/0x28b [44727.915784] ? do_raw_spin_unlock+0xcd/0xf8 [44727.915954] ? _raw_spin_unlock+0x27/0x31 [44727.916121] ? __handle_mm_fault+0x651/0xdb1 [44727.916290] ? check_chain_key+0xb0/0xfd [44727.916461] __sys_sendmsg+0x45/0x63 [44727.916626] ? __sys_sendmsg+0x45/0x63 [44727.916792] SyS_sendmsg+0x19/0x1b [44727.916950] entry_SYSCALL_64_fastpath+0x23/0xc2 [44727.917125] RIP: 0033:0x7ff8bbc96690 [44727.917286] RSP: 002b:00007ffc360991e8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [44727.917579] RAX: ffffffffffffffda RBX: ffffffff810d278c RCX: 00007ff8bbc96690 [44727.917783] RDX: 0000000000000000 RSI: 00007ffc36099230 RDI: 0000000000000003 [44727.917987] RBP: ffff880037217f98 R08: 0000000000000001 R09: 0000000000000003 [44727.918190] R10: 00007ffc36098fb0 R11: 0000000000000246 R12: 0000000000000006 [44727.918393] R13: 000000000066f1a0 R14: 00007ffc360a12e0 R15: 0000000000000000 [44727.918597] ? trace_hardirqs_off_caller+0xa7/0xcf [44727.918774] Code: 41 5f 5d c3 66 66 66 66 90 55 48 8d 56 04 45 31 c9 49 c7 c0 80 f3 b0 81 48 89 e5 41 55 41 54 53 48 89 fb 48 8d 7d a8 48 83 ec 48 <0f> b7 0e be 07 00 00 00 83 e9 04 e8 e6 f7 d8 ff 85 c0 0f 88 bb [44727.919332] RIP: cbq_init+0x27/0x205 RSP: ffff8800372175f0 [44727.919516] CR2: 0000000000000000 Fixes: 0fbbeb1ba43b ("[PKT_SCHED]: Fix missing qdisc_destroy() in qdisc_create_dflt()") Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
CBQ can fail on ->init by wrong nl attributes or simply for missing any,
f.e. if it's set as a default qdisc then TCA_OPTIONS (opt) will be NULL
when it is activated. The first thing init does is parse opt but it will
dereference a null pointer if used as a default qdisc, also since init
failure at default qdisc invokes ->reset() which cancels all timers then
we'll also dereference two more null pointers (timer->base) as they were
never initialized.

To reproduce:
$ sysctl net.core.default_qdisc=cbq
$ ip l set ethX up

Crash log of the first null ptr deref:
[44727.907454] BUG: unable to handle kernel NULL pointer dereference at (null)
[44727.907600] IP: cbq_init+0x27/0x205
[44727.907676] PGD 59ff4067
[44727.907677] P4D 59ff4067
[44727.907742] PUD 59c70067
[44727.907807] PMD 0
[44727.907873]
[44727.907982] Oops: 0000 [#1] SMP
[44727.908054] Modules linked in:
[44727.908126] CPU: 1 PID: 21312 Comm: ip Not tainted 4.13.0-rc6+ #60
[44727.908235] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
[44727.908477] task: ffff88005ad42700 task.stack: ffff880037214000
[44727.908672] RIP: 0010:cbq_init+0x27/0x205
[44727.908838] RSP: 0018:ffff8800372175f0 EFLAGS: 00010286
[44727.909018] RAX: ffffffff816c3852 RBX: ffff880058c53800 RCX: 0000000000000000
[44727.909222] RDX: 0000000000000004 RSI: 0000000000000000 RDI: ffff8800372175f8
[44727.909427] RBP: ffff880037217650 R08: ffffffff81b0f380 R09: 0000000000000000
[44727.909631] R10: ffff880037217660 R11: 0000000000000020 R12: ffffffff822a44c0
[44727.909835] R13: ffff880058b92000 R14: 00000000ffffffff R15: 0000000000000001
[44727.910040] FS:  00007ff8bc583740(0000) GS:ffff88005d880000(0000) knlGS:0000000000000000
[44727.910339] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[44727.910525] CR2: 0000000000000000 CR3: 00000000371e5000 CR4: 00000000000406e0
[44727.910731] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[44727.910936] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[44727.911141] Call Trace:
[44727.911291]  ? lockdep_init_map+0xb6/0x1ba
[44727.911461]  ? qdisc_alloc+0x14e/0x187
[44727.911626]  qdisc_create_dflt+0x7a/0x94
[44727.911794]  ? dev_activate+0x129/0x129
[44727.911959]  attach_one_default_qdisc+0x36/0x63
[44727.912132]  netdev_for_each_tx_queue+0x3d/0x48
[44727.912305]  dev_activate+0x4b/0x129
[44727.912468]  __dev_open+0xe7/0x104
[44727.912631]  __dev_change_flags+0xc6/0x15c
[44727.912799]  dev_change_flags+0x25/0x59
[44727.912966]  do_setlink+0x30c/0xb3f
[44727.913129]  ? check_chain_key+0xb0/0xfd
[44727.913294]  ? check_chain_key+0xb0/0xfd
[44727.913463]  rtnl_newlink+0x3a4/0x729
[44727.913626]  ? rtnl_newlink+0x117/0x729
[44727.913801]  ? ns_capable_common+0xd/0xb1
[44727.913968]  ? ns_capable+0x13/0x15
[44727.914131]  rtnetlink_rcv_msg+0x188/0x197
[44727.914300]  ? rcu_read_unlock+0x3e/0x5f
[44727.914465]  ? rtnl_newlink+0x729/0x729
[44727.914630]  netlink_rcv_skb+0x6c/0xce
[44727.914796]  rtnetlink_rcv+0x23/0x2a
[44727.914956]  netlink_unicast+0x103/0x181
[44727.915122]  netlink_sendmsg+0x326/0x337
[44727.915291]  sock_sendmsg_nosec+0x14/0x3f
[44727.915459]  sock_sendmsg+0x29/0x2e
[44727.915619]  ___sys_sendmsg+0x209/0x28b
[44727.915784]  ? do_raw_spin_unlock+0xcd/0xf8
[44727.915954]  ? _raw_spin_unlock+0x27/0x31
[44727.916121]  ? __handle_mm_fault+0x651/0xdb1
[44727.916290]  ? check_chain_key+0xb0/0xfd
[44727.916461]  __sys_sendmsg+0x45/0x63
[44727.916626]  ? __sys_sendmsg+0x45/0x63
[44727.916792]  SyS_sendmsg+0x19/0x1b
[44727.916950]  entry_SYSCALL_64_fastpath+0x23/0xc2
[44727.917125] RIP: 0033:0x7ff8bbc96690
[44727.917286] RSP: 002b:00007ffc360991e8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[44727.917579] RAX: ffffffffffffffda RBX: ffffffff810d278c RCX: 00007ff8bbc96690
[44727.917783] RDX: 0000000000000000 RSI: 00007ffc36099230 RDI: 0000000000000003
[44727.917987] RBP: ffff880037217f98 R08: 0000000000000001 R09: 0000000000000003
[44727.918190] R10: 00007ffc36098fb0 R11: 0000000000000246 R12: 0000000000000006
[44727.918393] R13: 000000000066f1a0 R14: 00007ffc360a12e0 R15: 0000000000000000
[44727.918597]  ? trace_hardirqs_off_caller+0xa7/0xcf
[44727.918774] Code: 41 5f 5d c3 66 66 66 66 90 55 48 8d 56 04 45 31 c9
49 c7 c0 80 f3 b0 81 48 89 e5 41 55 41 54 53 48 89 fb 48 8d 7d a8 48 83
ec 48 <0f> b7 0e be 07 00 00 00 83 e9 04 e8 e6 f7 d8 ff 85 c0 0f 88 bb
[44727.919332] RIP: cbq_init+0x27/0x205 RSP: ffff8800372175f0
[44727.919516] CR2: 0000000000000000

Fixes: 0fbbeb1ba43b ("[PKT_SCHED]: Fix missing qdisc_destroy() in qdisc_create_dflt()")
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sch_hfsc: fix null pointer deref and double free on init failure 2017-08-30T22:26:11+00:00 Nikolay Aleksandrov nikolay@cumulusnetworks.com 2017-08-30T09:49:00+00:00 3bdac362a2f89ed3e148fa6f38c5f5d858f50b1a Depending on where ->init fails we can get a null pointer deref due to uninitialized hires timer (watchdog) or a double free of the qdisc hash because it is already freed by ->destroy(). Fixes: 8d5537387505 ("net/sched/hfsc: allocate tcf block for hfsc root class") Fixes: 87b60cfacf9f ("net_sched: fix error recovery at qdisc creation") Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
Depending on where ->init fails we can get a null pointer deref due to
uninitialized hires timer (watchdog) or a double free of the qdisc hash
because it is already freed by ->destroy().

Fixes: 8d5537387505 ("net/sched/hfsc: allocate tcf block for hfsc root class")
Fixes: 87b60cfacf9f ("net_sched: fix error recovery at qdisc creation")
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sch_hhf: fix null pointer dereference on init failure 2017-08-30T22:26:11+00:00 Nikolay Aleksandrov nikolay@cumulusnetworks.com 2017-08-30T09:48:59+00:00 32db864d33c21fd70a217ba53cb7224889354ffb If sch_hhf fails in its ->init() function (either due to wrong user-space arguments as below or memory alloc failure of hh_flows) it will do a null pointer deref of q->hh_flows in its ->destroy() function. To reproduce the crash: $ tc qdisc add dev eth0 root hhf quantum 2000000 non_hh_weight 10000000 Crash log: [ 690.654882] BUG: unable to handle kernel NULL pointer dereference at (null) [ 690.655565] IP: hhf_destroy+0x48/0xbc [ 690.655944] PGD 37345067 [ 690.655948] P4D 37345067 [ 690.656252] PUD 58402067 [ 690.656554] PMD 0 [ 690.656857] [ 690.657362] Oops: 0000 [#1] SMP [ 690.657696] Modules linked in: [ 690.658032] CPU: 3 PID: 920 Comm: tc Not tainted 4.13.0-rc6+ #57 [ 690.658525] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014 [ 690.659255] task: ffff880058578000 task.stack: ffff88005acbc000 [ 690.659747] RIP: 0010:hhf_destroy+0x48/0xbc [ 690.660146] RSP: 0018:ffff88005acbf9e0 EFLAGS: 00010246 [ 690.660601] RAX: 0000000000000000 RBX: 0000000000000020 RCX: 0000000000000000 [ 690.661155] RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff821f63f0 [ 690.661710] RBP: ffff88005acbfa08 R08: ffffffff81b10a90 R09: 0000000000000000 [ 690.662267] R10: 00000000f42b7019 R11: ffff880058578000 R12: 00000000ffffffea [ 690.662820] R13: ffff8800372f6400 R14: 0000000000000000 R15: 0000000000000000 [ 690.663769] FS: 00007f8ae5e8b740(0000) GS:ffff88005d980000(0000) knlGS:0000000000000000 [ 690.667069] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 690.667965] CR2: 0000000000000000 CR3: 0000000058523000 CR4: 00000000000406e0 [ 690.668918] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 690.669945] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 690.671003] Call Trace: [ 690.671743] qdisc_create+0x377/0x3fd [ 690.672534] tc_modify_qdisc+0x4d2/0x4fd [ 690.673324] rtnetlink_rcv_msg+0x188/0x197 [ 690.674204] ? rcu_read_unlock+0x3e/0x5f [ 690.675091] ? rtnl_newlink+0x729/0x729 [ 690.675877] netlink_rcv_skb+0x6c/0xce [ 690.676648] rtnetlink_rcv+0x23/0x2a [ 690.677405] netlink_unicast+0x103/0x181 [ 690.678179] netlink_sendmsg+0x326/0x337 [ 690.678958] sock_sendmsg_nosec+0x14/0x3f [ 690.679743] sock_sendmsg+0x29/0x2e [ 690.680506] ___sys_sendmsg+0x209/0x28b [ 690.681283] ? __handle_mm_fault+0xc7d/0xdb1 [ 690.681915] ? check_chain_key+0xb0/0xfd [ 690.682449] __sys_sendmsg+0x45/0x63 [ 690.682954] ? __sys_sendmsg+0x45/0x63 [ 690.683471] SyS_sendmsg+0x19/0x1b [ 690.683974] entry_SYSCALL_64_fastpath+0x23/0xc2 [ 690.684516] RIP: 0033:0x7f8ae529d690 [ 690.685016] RSP: 002b:00007fff26d2d6b8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 690.685931] RAX: ffffffffffffffda RBX: ffffffff810d278c RCX: 00007f8ae529d690 [ 690.686573] RDX: 0000000000000000 RSI: 00007fff26d2d700 RDI: 0000000000000003 [ 690.687047] RBP: ffff88005acbff98 R08: 0000000000000001 R09: 0000000000000000 [ 690.687519] R10: 00007fff26d2d480 R11: 0000000000000246 R12: 0000000000000002 [ 690.687996] R13: 0000000001258070 R14: 0000000000000001 R15: 0000000000000000 [ 690.688475] ? trace_hardirqs_off_caller+0xa7/0xcf [ 690.688887] Code: 00 00 e8 2a 02 ae ff 49 8b bc 1d 60 02 00 00 48 83 c3 08 e8 19 02 ae ff 48 83 fb 20 75 dc 45 31 f6 4d 89 f7 4d 03 bd 20 02 00 00 <49> 8b 07 49 39 c7 75 24 49 83 c6 10 49 81 fe 00 40 00 00 75 e1 [ 690.690200] RIP: hhf_destroy+0x48/0xbc RSP: ffff88005acbf9e0 [ 690.690636] CR2: 0000000000000000 Fixes: 87b60cfacf9f ("net_sched: fix error recovery at qdisc creation") Fixes: 10239edf86f1 ("net-qdisc-hhf: Heavy-Hitter Filter (HHF) qdisc") Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
If sch_hhf fails in its ->init() function (either due to wrong
user-space arguments as below or memory alloc failure of hh_flows) it
will do a null pointer deref of q->hh_flows in its ->destroy() function.

To reproduce the crash:
$ tc qdisc add dev eth0 root hhf quantum 2000000 non_hh_weight 10000000

Crash log:
[  690.654882] BUG: unable to handle kernel NULL pointer dereference at (null)
[  690.655565] IP: hhf_destroy+0x48/0xbc
[  690.655944] PGD 37345067
[  690.655948] P4D 37345067
[  690.656252] PUD 58402067
[  690.656554] PMD 0
[  690.656857]
[  690.657362] Oops: 0000 [#1] SMP
[  690.657696] Modules linked in:
[  690.658032] CPU: 3 PID: 920 Comm: tc Not tainted 4.13.0-rc6+ #57
[  690.658525] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
[  690.659255] task: ffff880058578000 task.stack: ffff88005acbc000
[  690.659747] RIP: 0010:hhf_destroy+0x48/0xbc
[  690.660146] RSP: 0018:ffff88005acbf9e0 EFLAGS: 00010246
[  690.660601] RAX: 0000000000000000 RBX: 0000000000000020 RCX: 0000000000000000
[  690.661155] RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff821f63f0
[  690.661710] RBP: ffff88005acbfa08 R08: ffffffff81b10a90 R09: 0000000000000000
[  690.662267] R10: 00000000f42b7019 R11: ffff880058578000 R12: 00000000ffffffea
[  690.662820] R13: ffff8800372f6400 R14: 0000000000000000 R15: 0000000000000000
[  690.663769] FS:  00007f8ae5e8b740(0000) GS:ffff88005d980000(0000) knlGS:0000000000000000
[  690.667069] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  690.667965] CR2: 0000000000000000 CR3: 0000000058523000 CR4: 00000000000406e0
[  690.668918] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  690.669945] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  690.671003] Call Trace:
[  690.671743]  qdisc_create+0x377/0x3fd
[  690.672534]  tc_modify_qdisc+0x4d2/0x4fd
[  690.673324]  rtnetlink_rcv_msg+0x188/0x197
[  690.674204]  ? rcu_read_unlock+0x3e/0x5f
[  690.675091]  ? rtnl_newlink+0x729/0x729
[  690.675877]  netlink_rcv_skb+0x6c/0xce
[  690.676648]  rtnetlink_rcv+0x23/0x2a
[  690.677405]  netlink_unicast+0x103/0x181
[  690.678179]  netlink_sendmsg+0x326/0x337
[  690.678958]  sock_sendmsg_nosec+0x14/0x3f
[  690.679743]  sock_sendmsg+0x29/0x2e
[  690.680506]  ___sys_sendmsg+0x209/0x28b
[  690.681283]  ? __handle_mm_fault+0xc7d/0xdb1
[  690.681915]  ? check_chain_key+0xb0/0xfd
[  690.682449]  __sys_sendmsg+0x45/0x63
[  690.682954]  ? __sys_sendmsg+0x45/0x63
[  690.683471]  SyS_sendmsg+0x19/0x1b
[  690.683974]  entry_SYSCALL_64_fastpath+0x23/0xc2
[  690.684516] RIP: 0033:0x7f8ae529d690
[  690.685016] RSP: 002b:00007fff26d2d6b8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[  690.685931] RAX: ffffffffffffffda RBX: ffffffff810d278c RCX: 00007f8ae529d690
[  690.686573] RDX: 0000000000000000 RSI: 00007fff26d2d700 RDI: 0000000000000003
[  690.687047] RBP: ffff88005acbff98 R08: 0000000000000001 R09: 0000000000000000
[  690.687519] R10: 00007fff26d2d480 R11: 0000000000000246 R12: 0000000000000002
[  690.687996] R13: 0000000001258070 R14: 0000000000000001 R15: 0000000000000000
[  690.688475]  ? trace_hardirqs_off_caller+0xa7/0xcf
[  690.688887] Code: 00 00 e8 2a 02 ae ff 49 8b bc 1d 60 02 00 00 48 83
c3 08 e8 19 02 ae ff 48 83 fb 20 75 dc 45 31 f6 4d 89 f7 4d 03 bd 20 02
00 00 <49> 8b 07 49 39 c7 75 24 49 83 c6 10 49 81 fe 00 40 00 00 75 e1
[  690.690200] RIP: hhf_destroy+0x48/0xbc RSP: ffff88005acbf9e0
[  690.690636] CR2: 0000000000000000

Fixes: 87b60cfacf9f ("net_sched: fix error recovery at qdisc creation")
Fixes: 10239edf86f1 ("net-qdisc-hhf: Heavy-Hitter Filter (HHF) qdisc")
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sch_multiq: fix double free on init failure 2017-08-30T22:26:11+00:00 Nikolay Aleksandrov nikolay@cumulusnetworks.com 2017-08-30T09:48:58+00:00 e89d469e3be3ed3d7124a803211a463ff83d0964 The below commit added a call to ->destroy() on init failure, but multiq still frees ->queues on error in init, but ->queues is also freed by ->destroy() thus we get double free and corrupted memory. Very easy to reproduce (eth0 not multiqueue): $ tc qdisc add dev eth0 root multiq RTNETLINK answers: Operation not supported $ ip l add dumdum type dummy (crash) Trace log: [ 3929.467747] general protection fault: 0000 [#1] SMP [ 3929.468083] Modules linked in: [ 3929.468302] CPU: 3 PID: 967 Comm: ip Not tainted 4.13.0-rc6+ #56 [ 3929.468625] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014 [ 3929.469124] task: ffff88003716a700 task.stack: ffff88005872c000 [ 3929.469449] RIP: 0010:__kmalloc_track_caller+0x117/0x1be [ 3929.469746] RSP: 0018:ffff88005872f6a0 EFLAGS: 00010246 [ 3929.470042] RAX: 00000000000002de RBX: 0000000058a59000 RCX: 00000000000002df [ 3929.470406] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff821f7020 [ 3929.470770] RBP: ffff88005872f6e8 R08: 000000000001f010 R09: 0000000000000000 [ 3929.471133] R10: ffff88005872f730 R11: 0000000000008cdd R12: ff006d75646d7564 [ 3929.471496] R13: 00000000014000c0 R14: ffff88005b403c00 R15: ffff88005b403c00 [ 3929.471869] FS: 00007f0b70480740(0000) GS:ffff88005d980000(0000) knlGS:0000000000000000 [ 3929.472286] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 3929.472677] CR2: 00007ffcee4f3000 CR3: 0000000059d45000 CR4: 00000000000406e0 [ 3929.473209] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 3929.474109] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 3929.474873] Call Trace: [ 3929.475337] ? kstrdup_const+0x23/0x25 [ 3929.475863] kstrdup+0x2e/0x4b [ 3929.476338] kstrdup_const+0x23/0x25 [ 3929.478084] __kernfs_new_node+0x28/0xbc [ 3929.478478] kernfs_new_node+0x35/0x55 [ 3929.478929] kernfs_create_link+0x23/0x76 [ 3929.479478] sysfs_do_create_link_sd.isra.2+0x85/0xd7 [ 3929.480096] sysfs_create_link+0x33/0x35 [ 3929.480649] device_add+0x200/0x589 [ 3929.481184] netdev_register_kobject+0x7c/0x12f [ 3929.481711] register_netdevice+0x373/0x471 [ 3929.482174] rtnl_newlink+0x614/0x729 [ 3929.482610] ? rtnl_newlink+0x17f/0x729 [ 3929.483080] rtnetlink_rcv_msg+0x188/0x197 [ 3929.483533] ? rcu_read_unlock+0x3e/0x5f [ 3929.483984] ? rtnl_newlink+0x729/0x729 [ 3929.484420] netlink_rcv_skb+0x6c/0xce [ 3929.484858] rtnetlink_rcv+0x23/0x2a [ 3929.485291] netlink_unicast+0x103/0x181 [ 3929.485735] netlink_sendmsg+0x326/0x337 [ 3929.486181] sock_sendmsg_nosec+0x14/0x3f [ 3929.486614] sock_sendmsg+0x29/0x2e [ 3929.486973] ___sys_sendmsg+0x209/0x28b [ 3929.487340] ? do_raw_spin_unlock+0xcd/0xf8 [ 3929.487719] ? _raw_spin_unlock+0x27/0x31 [ 3929.488092] ? __handle_mm_fault+0x651/0xdb1 [ 3929.488471] ? check_chain_key+0xb0/0xfd [ 3929.488847] __sys_sendmsg+0x45/0x63 [ 3929.489206] ? __sys_sendmsg+0x45/0x63 [ 3929.489576] SyS_sendmsg+0x19/0x1b [ 3929.489901] entry_SYSCALL_64_fastpath+0x23/0xc2 [ 3929.490172] RIP: 0033:0x7f0b6fb93690 [ 3929.490423] RSP: 002b:00007ffcee4ed588 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 3929.490881] RAX: ffffffffffffffda RBX: ffffffff810d278c RCX: 00007f0b6fb93690 [ 3929.491198] RDX: 0000000000000000 RSI: 00007ffcee4ed5d0 RDI: 0000000000000003 [ 3929.491521] RBP: ffff88005872ff98 R08: 0000000000000001 R09: 0000000000000000 [ 3929.491801] R10: 00007ffcee4ed350 R11: 0000000000000246 R12: 0000000000000002 [ 3929.492075] R13: 000000000066f1a0 R14: 00007ffcee4f5680 R15: 0000000000000000 [ 3929.492352] ? trace_hardirqs_off_caller+0xa7/0xcf [ 3929.492590] Code: 8b 45 c0 48 8b 45 b8 74 17 48 8b 4d c8 83 ca ff 44 89 ee 4c 89 f7 e8 83 ca ff ff 49 89 c4 eb 49 49 63 56 20 48 8d 48 01 4d 8b 06 <49> 8b 1c 14 48 89 c2 4c 89 e0 65 49 0f c7 08 0f 94 c0 83 f0 01 [ 3929.493335] RIP: __kmalloc_track_caller+0x117/0x1be RSP: ffff88005872f6a0 Fixes: 87b60cfacf9f ("net_sched: fix error recovery at qdisc creation") Fixes: f07d1501292b ("multiq: Further multiqueue cleanup") Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
The below commit added a call to ->destroy() on init failure, but multiq
still frees ->queues on error in init, but ->queues is also freed by
->destroy() thus we get double free and corrupted memory.

Very easy to reproduce (eth0 not multiqueue):
$ tc qdisc add dev eth0 root multiq
RTNETLINK answers: Operation not supported
$ ip l add dumdum type dummy
(crash)

Trace log:
[ 3929.467747] general protection fault: 0000 [#1] SMP
[ 3929.468083] Modules linked in:
[ 3929.468302] CPU: 3 PID: 967 Comm: ip Not tainted 4.13.0-rc6+ #56
[ 3929.468625] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
[ 3929.469124] task: ffff88003716a700 task.stack: ffff88005872c000
[ 3929.469449] RIP: 0010:__kmalloc_track_caller+0x117/0x1be
[ 3929.469746] RSP: 0018:ffff88005872f6a0 EFLAGS: 00010246
[ 3929.470042] RAX: 00000000000002de RBX: 0000000058a59000 RCX: 00000000000002df
[ 3929.470406] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff821f7020
[ 3929.470770] RBP: ffff88005872f6e8 R08: 000000000001f010 R09: 0000000000000000
[ 3929.471133] R10: ffff88005872f730 R11: 0000000000008cdd R12: ff006d75646d7564
[ 3929.471496] R13: 00000000014000c0 R14: ffff88005b403c00 R15: ffff88005b403c00
[ 3929.471869] FS:  00007f0b70480740(0000) GS:ffff88005d980000(0000) knlGS:0000000000000000
[ 3929.472286] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 3929.472677] CR2: 00007ffcee4f3000 CR3: 0000000059d45000 CR4: 00000000000406e0
[ 3929.473209] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 3929.474109] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 3929.474873] Call Trace:
[ 3929.475337]  ? kstrdup_const+0x23/0x25
[ 3929.475863]  kstrdup+0x2e/0x4b
[ 3929.476338]  kstrdup_const+0x23/0x25
[ 3929.478084]  __kernfs_new_node+0x28/0xbc
[ 3929.478478]  kernfs_new_node+0x35/0x55
[ 3929.478929]  kernfs_create_link+0x23/0x76
[ 3929.479478]  sysfs_do_create_link_sd.isra.2+0x85/0xd7
[ 3929.480096]  sysfs_create_link+0x33/0x35
[ 3929.480649]  device_add+0x200/0x589
[ 3929.481184]  netdev_register_kobject+0x7c/0x12f
[ 3929.481711]  register_netdevice+0x373/0x471
[ 3929.482174]  rtnl_newlink+0x614/0x729
[ 3929.482610]  ? rtnl_newlink+0x17f/0x729
[ 3929.483080]  rtnetlink_rcv_msg+0x188/0x197
[ 3929.483533]  ? rcu_read_unlock+0x3e/0x5f
[ 3929.483984]  ? rtnl_newlink+0x729/0x729
[ 3929.484420]  netlink_rcv_skb+0x6c/0xce
[ 3929.484858]  rtnetlink_rcv+0x23/0x2a
[ 3929.485291]  netlink_unicast+0x103/0x181
[ 3929.485735]  netlink_sendmsg+0x326/0x337
[ 3929.486181]  sock_sendmsg_nosec+0x14/0x3f
[ 3929.486614]  sock_sendmsg+0x29/0x2e
[ 3929.486973]  ___sys_sendmsg+0x209/0x28b
[ 3929.487340]  ? do_raw_spin_unlock+0xcd/0xf8
[ 3929.487719]  ? _raw_spin_unlock+0x27/0x31
[ 3929.488092]  ? __handle_mm_fault+0x651/0xdb1
[ 3929.488471]  ? check_chain_key+0xb0/0xfd
[ 3929.488847]  __sys_sendmsg+0x45/0x63
[ 3929.489206]  ? __sys_sendmsg+0x45/0x63
[ 3929.489576]  SyS_sendmsg+0x19/0x1b
[ 3929.489901]  entry_SYSCALL_64_fastpath+0x23/0xc2
[ 3929.490172] RIP: 0033:0x7f0b6fb93690
[ 3929.490423] RSP: 002b:00007ffcee4ed588 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[ 3929.490881] RAX: ffffffffffffffda RBX: ffffffff810d278c RCX: 00007f0b6fb93690
[ 3929.491198] RDX: 0000000000000000 RSI: 00007ffcee4ed5d0 RDI: 0000000000000003
[ 3929.491521] RBP: ffff88005872ff98 R08: 0000000000000001 R09: 0000000000000000
[ 3929.491801] R10: 00007ffcee4ed350 R11: 0000000000000246 R12: 0000000000000002
[ 3929.492075] R13: 000000000066f1a0 R14: 00007ffcee4f5680 R15: 0000000000000000
[ 3929.492352]  ? trace_hardirqs_off_caller+0xa7/0xcf
[ 3929.492590] Code: 8b 45 c0 48 8b 45 b8 74 17 48 8b 4d c8 83 ca ff 44
89 ee 4c 89 f7 e8 83 ca ff ff 49 89 c4 eb 49 49 63 56 20 48 8d 48 01 4d
8b 06 <49> 8b 1c 14 48 89 c2 4c 89 e0 65 49 0f c7 08 0f 94 c0 83 f0 01
[ 3929.493335] RIP: __kmalloc_track_caller+0x117/0x1be RSP: ffff88005872f6a0

Fixes: 87b60cfacf9f ("net_sched: fix error recovery at qdisc creation")
Fixes: f07d1501292b ("multiq: Further multiqueue cleanup")
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sch_htb: fix crash on init failure 2017-08-30T22:26:11+00:00 Nikolay Aleksandrov nikolay@cumulusnetworks.com 2017-08-30T09:48:57+00:00 88c2ace69dbef696edba77712882af03879abc9c The commit below added a call to the ->destroy() callback for all qdiscs which failed in their ->init(), but some were not prepared for such change and can't handle partially initialized qdisc. HTB is one of them and if any error occurs before the qdisc watchdog timer and qdisc work are initialized then we can hit either a null ptr deref (timer->base) when canceling in ->destroy or lockdep error info about trying to register a non-static key and a stack dump. So to fix these two move the watchdog timer and workqueue init before anything that can err out. To reproduce userspace needs to send broken htb qdisc create request, tested with a modified tc (q_htb.c). Trace log: [ 2710.897602] BUG: unable to handle kernel NULL pointer dereference at (null) [ 2710.897977] IP: hrtimer_active+0x17/0x8a [ 2710.898174] PGD 58fab067 [ 2710.898175] P4D 58fab067 [ 2710.898353] PUD 586c0067 [ 2710.898531] PMD 0 [ 2710.898710] [ 2710.899045] Oops: 0000 [#1] SMP [ 2710.899232] Modules linked in: [ 2710.899419] CPU: 1 PID: 950 Comm: tc Not tainted 4.13.0-rc6+ #54 [ 2710.899646] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014 [ 2710.900035] task: ffff880059ed2700 task.stack: ffff88005ad4c000 [ 2710.900262] RIP: 0010:hrtimer_active+0x17/0x8a [ 2710.900467] RSP: 0018:ffff88005ad4f960 EFLAGS: 00010246 [ 2710.900684] RAX: 0000000000000000 RBX: ffff88003701e298 RCX: 0000000000000000 [ 2710.900933] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88003701e298 [ 2710.901177] RBP: ffff88005ad4f980 R08: 0000000000000001 R09: 0000000000000001 [ 2710.901419] R10: ffff88005ad4f800 R11: 0000000000000400 R12: 0000000000000000 [ 2710.901663] R13: ffff88003701e298 R14: ffffffff822a4540 R15: ffff88005ad4fac0 [ 2710.901907] FS: 00007f2f5e90f740(0000) GS:ffff88005d880000(0000) knlGS:0000000000000000 [ 2710.902277] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 2710.902500] CR2: 0000000000000000 CR3: 0000000058ca3000 CR4: 00000000000406e0 [ 2710.902744] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 2710.902977] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 2710.903180] Call Trace: [ 2710.903332] hrtimer_try_to_cancel+0x1a/0x93 [ 2710.903504] hrtimer_cancel+0x15/0x20 [ 2710.903667] qdisc_watchdog_cancel+0x12/0x14 [ 2710.903866] htb_destroy+0x2e/0xf7 [ 2710.904097] qdisc_create+0x377/0x3fd [ 2710.904330] tc_modify_qdisc+0x4d2/0x4fd [ 2710.904511] rtnetlink_rcv_msg+0x188/0x197 [ 2710.904682] ? rcu_read_unlock+0x3e/0x5f [ 2710.904849] ? rtnl_newlink+0x729/0x729 [ 2710.905017] netlink_rcv_skb+0x6c/0xce [ 2710.905183] rtnetlink_rcv+0x23/0x2a [ 2710.905345] netlink_unicast+0x103/0x181 [ 2710.905511] netlink_sendmsg+0x326/0x337 [ 2710.905679] sock_sendmsg_nosec+0x14/0x3f [ 2710.905847] sock_sendmsg+0x29/0x2e [ 2710.906010] ___sys_sendmsg+0x209/0x28b [ 2710.906176] ? do_raw_spin_unlock+0xcd/0xf8 [ 2710.906346] ? _raw_spin_unlock+0x27/0x31 [ 2710.906514] ? __handle_mm_fault+0x651/0xdb1 [ 2710.906685] ? check_chain_key+0xb0/0xfd [ 2710.906855] __sys_sendmsg+0x45/0x63 [ 2710.907018] ? __sys_sendmsg+0x45/0x63 [ 2710.907185] SyS_sendmsg+0x19/0x1b [ 2710.907344] entry_SYSCALL_64_fastpath+0x23/0xc2 Note that probably this bug goes further back because the default qdisc handling always calls ->destroy on init failure too. Fixes: 87b60cfacf9f ("net_sched: fix error recovery at qdisc creation") Fixes: 0fbbeb1ba43b ("[PKT_SCHED]: Fix missing qdisc_destroy() in qdisc_create_dflt()") Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
The commit below added a call to the ->destroy() callback for all qdiscs
which failed in their ->init(), but some were not prepared for such
change and can't handle partially initialized qdisc. HTB is one of them
and if any error occurs before the qdisc watchdog timer and qdisc work are
initialized then we can hit either a null ptr deref (timer->base) when
canceling in ->destroy or lockdep error info about trying to register
a non-static key and a stack dump. So to fix these two move the watchdog
timer and workqueue init before anything that can err out.
To reproduce userspace needs to send broken htb qdisc create request,
tested with a modified tc (q_htb.c).

Trace log:
[ 2710.897602] BUG: unable to handle kernel NULL pointer dereference at (null)
[ 2710.897977] IP: hrtimer_active+0x17/0x8a
[ 2710.898174] PGD 58fab067
[ 2710.898175] P4D 58fab067
[ 2710.898353] PUD 586c0067
[ 2710.898531] PMD 0
[ 2710.898710]
[ 2710.899045] Oops: 0000 [#1] SMP
[ 2710.899232] Modules linked in:
[ 2710.899419] CPU: 1 PID: 950 Comm: tc Not tainted 4.13.0-rc6+ #54
[ 2710.899646] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
[ 2710.900035] task: ffff880059ed2700 task.stack: ffff88005ad4c000
[ 2710.900262] RIP: 0010:hrtimer_active+0x17/0x8a
[ 2710.900467] RSP: 0018:ffff88005ad4f960 EFLAGS: 00010246
[ 2710.900684] RAX: 0000000000000000 RBX: ffff88003701e298 RCX: 0000000000000000
[ 2710.900933] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88003701e298
[ 2710.901177] RBP: ffff88005ad4f980 R08: 0000000000000001 R09: 0000000000000001
[ 2710.901419] R10: ffff88005ad4f800 R11: 0000000000000400 R12: 0000000000000000
[ 2710.901663] R13: ffff88003701e298 R14: ffffffff822a4540 R15: ffff88005ad4fac0
[ 2710.901907] FS:  00007f2f5e90f740(0000) GS:ffff88005d880000(0000) knlGS:0000000000000000
[ 2710.902277] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 2710.902500] CR2: 0000000000000000 CR3: 0000000058ca3000 CR4: 00000000000406e0
[ 2710.902744] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 2710.902977] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 2710.903180] Call Trace:
[ 2710.903332]  hrtimer_try_to_cancel+0x1a/0x93
[ 2710.903504]  hrtimer_cancel+0x15/0x20
[ 2710.903667]  qdisc_watchdog_cancel+0x12/0x14
[ 2710.903866]  htb_destroy+0x2e/0xf7
[ 2710.904097]  qdisc_create+0x377/0x3fd
[ 2710.904330]  tc_modify_qdisc+0x4d2/0x4fd
[ 2710.904511]  rtnetlink_rcv_msg+0x188/0x197
[ 2710.904682]  ? rcu_read_unlock+0x3e/0x5f
[ 2710.904849]  ? rtnl_newlink+0x729/0x729
[ 2710.905017]  netlink_rcv_skb+0x6c/0xce
[ 2710.905183]  rtnetlink_rcv+0x23/0x2a
[ 2710.905345]  netlink_unicast+0x103/0x181
[ 2710.905511]  netlink_sendmsg+0x326/0x337
[ 2710.905679]  sock_sendmsg_nosec+0x14/0x3f
[ 2710.905847]  sock_sendmsg+0x29/0x2e
[ 2710.906010]  ___sys_sendmsg+0x209/0x28b
[ 2710.906176]  ? do_raw_spin_unlock+0xcd/0xf8
[ 2710.906346]  ? _raw_spin_unlock+0x27/0x31
[ 2710.906514]  ? __handle_mm_fault+0x651/0xdb1
[ 2710.906685]  ? check_chain_key+0xb0/0xfd
[ 2710.906855]  __sys_sendmsg+0x45/0x63
[ 2710.907018]  ? __sys_sendmsg+0x45/0x63
[ 2710.907185]  SyS_sendmsg+0x19/0x1b
[ 2710.907344]  entry_SYSCALL_64_fastpath+0x23/0xc2

Note that probably this bug goes further back because the default qdisc
handling always calls ->destroy on init failure too.

Fixes: 87b60cfacf9f ("net_sched: fix error recovery at qdisc creation")
Fixes: 0fbbeb1ba43b ("[PKT_SCHED]: Fix missing qdisc_destroy() in qdisc_create_dflt()")
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net_sched: fix a refcount_t issue with noop_qdisc 2017-08-25T04:28:24+00:00 Eric Dumazet edumazet@google.com 2017-08-25T04:12:28+00:00 551143d8d954fe398324a5caa276f518466c428b syzkaller reported a refcount_t warning [1] Issue here is that noop_qdisc refcnt was never really considered as a true refcount, since qdisc_destroy() found TCQ_F_BUILTIN set : if (qdisc->flags & TCQ_F_BUILTIN || !refcount_dec_and_test(&qdisc->refcnt))) return; Meaning that all atomic_inc() we did on noop_qdisc.refcnt were not really needed, but harmless until refcount_t came. To fix this problem, we simply need to not increment noop_qdisc.refcnt, since we never decrement it. [1] refcount_t: increment on 0; use-after-free. ------------[ cut here ]------------ WARNING: CPU: 0 PID: 21754 at lib/refcount.c:152 refcount_inc+0x47/0x50 lib/refcount.c:152 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 21754 Comm: syz-executor7 Not tainted 4.13.0-rc6+ #20 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:52 panic+0x1e4/0x417 kernel/panic.c:180 __warn+0x1c4/0x1d9 kernel/panic.c:541 report_bug+0x211/0x2d0 lib/bug.c:183 fixup_bug+0x40/0x90 arch/x86/kernel/traps.c:190 do_trap_no_signal arch/x86/kernel/traps.c:224 [inline] do_trap+0x260/0x390 arch/x86/kernel/traps.c:273 do_error_trap+0x120/0x390 arch/x86/kernel/traps.c:310 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:323 invalid_op+0x1e/0x30 arch/x86/entry/entry_64.S:846 RIP: 0010:refcount_inc+0x47/0x50 lib/refcount.c:152 RSP: 0018:ffff8801c43477a0 EFLAGS: 00010282 RAX: 000000000000002b RBX: ffffffff86093c14 RCX: 0000000000000000 RDX: 000000000000002b RSI: ffffffff8159314e RDI: ffffed0038868ee8 RBP: ffff8801c43477a8 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff86093ac0 R13: 0000000000000001 R14: ffff8801d0f3bac0 R15: dffffc0000000000 attach_default_qdiscs net/sched/sch_generic.c:792 [inline] dev_activate+0x7d3/0xaa0 net/sched/sch_generic.c:833 __dev_open+0x227/0x330 net/core/dev.c:1380 __dev_change_flags+0x695/0x990 net/core/dev.c:6726 dev_change_flags+0x88/0x140 net/core/dev.c:6792 dev_ifsioc+0x5a6/0x930 net/core/dev_ioctl.c:256 dev_ioctl+0x2bc/0xf90 net/core/dev_ioctl.c:554 sock_do_ioctl+0x94/0xb0 net/socket.c:968 sock_ioctl+0x2c2/0x440 net/socket.c:1058 vfs_ioctl fs/ioctl.c:45 [inline] do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:685 SYSC_ioctl fs/ioctl.c:700 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691 Fixes: 7b9364050246 ("net, sched: convert Qdisc.refcnt from atomic_t to refcount_t") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Cc: Reshetova, Elena <elena.reshetova@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
syzkaller reported a refcount_t warning [1]

Issue here is that noop_qdisc refcnt was never really considered as
a true refcount, since qdisc_destroy() found TCQ_F_BUILTIN set :

if (qdisc->flags & TCQ_F_BUILTIN ||
    !refcount_dec_and_test(&qdisc->refcnt)))
	return;

Meaning that all atomic_inc() we did on noop_qdisc.refcnt were not
really needed, but harmless until refcount_t came.

To fix this problem, we simply need to not increment noop_qdisc.refcnt,
since we never decrement it.

[1]
refcount_t: increment on 0; use-after-free.
------------[ cut here ]------------
WARNING: CPU: 0 PID: 21754 at lib/refcount.c:152 refcount_inc+0x47/0x50 lib/refcount.c:152
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 21754 Comm: syz-executor7 Not tainted 4.13.0-rc6+ #20
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:52
 panic+0x1e4/0x417 kernel/panic.c:180
 __warn+0x1c4/0x1d9 kernel/panic.c:541
 report_bug+0x211/0x2d0 lib/bug.c:183
 fixup_bug+0x40/0x90 arch/x86/kernel/traps.c:190
 do_trap_no_signal arch/x86/kernel/traps.c:224 [inline]
 do_trap+0x260/0x390 arch/x86/kernel/traps.c:273
 do_error_trap+0x120/0x390 arch/x86/kernel/traps.c:310
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:323
 invalid_op+0x1e/0x30 arch/x86/entry/entry_64.S:846
RIP: 0010:refcount_inc+0x47/0x50 lib/refcount.c:152
RSP: 0018:ffff8801c43477a0 EFLAGS: 00010282
RAX: 000000000000002b RBX: ffffffff86093c14 RCX: 0000000000000000
RDX: 000000000000002b RSI: ffffffff8159314e RDI: ffffed0038868ee8
RBP: ffff8801c43477a8 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff86093ac0
R13: 0000000000000001 R14: ffff8801d0f3bac0 R15: dffffc0000000000
 attach_default_qdiscs net/sched/sch_generic.c:792 [inline]
 dev_activate+0x7d3/0xaa0 net/sched/sch_generic.c:833
 __dev_open+0x227/0x330 net/core/dev.c:1380
 __dev_change_flags+0x695/0x990 net/core/dev.c:6726
 dev_change_flags+0x88/0x140 net/core/dev.c:6792
 dev_ifsioc+0x5a6/0x930 net/core/dev_ioctl.c:256
 dev_ioctl+0x2bc/0xf90 net/core/dev_ioctl.c:554
 sock_do_ioctl+0x94/0xb0 net/socket.c:968
 sock_ioctl+0x2c2/0x440 net/socket.c:1058
 vfs_ioctl fs/ioctl.c:45 [inline]
 do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:685
 SYSC_ioctl fs/ioctl.c:700 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691

Fixes: 7b9364050246 ("net, sched: convert Qdisc.refcnt from atomic_t to refcount_t")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Reshetova, Elena <elena.reshetova@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>