linux.git/net/sched/act_sample.c, branch v5.1 Linux kernel source tree net/sched: act_sample: fix divide by zero in the traffic path 2019-04-04T17:46:33+00:00 Davide Caratti dcaratti@redhat.com 2019-04-04T10:31:35+00:00 fae2708174ae95d98d19f194e03d6e8f688ae195 the control path of 'sample' action does not validate the value of 'rate' provided by the user, but then it uses it as divisor in the traffic path. Validate it in tcf_sample_init(), and return -EINVAL with a proper extack message in case that value is zero, to fix a splat with the script below: # tc f a dev test0 egress matchall action sample rate 0 group 1 index 2 # tc -s a s action sample total acts 1 action order 0: sample rate 1/0 group 1 pipe index 2 ref 1 bind 1 installed 19 sec used 19 sec Action statistics: Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 # ping 192.0.2.1 -I test0 -c1 -q divide error: 0000 [#1] SMP PTI CPU: 1 PID: 6192 Comm: ping Not tainted 5.1.0-rc2.diag2+ #591 Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 RIP: 0010:tcf_sample_act+0x9e/0x1e0 [act_sample] Code: 6a f1 85 c0 74 0d 80 3d 83 1a 00 00 00 0f 84 9c 00 00 00 4d 85 e4 0f 84 85 00 00 00 e8 9b d7 9c f1 44 8b 8b e0 00 00 00 31 d2 <41> f7 f1 85 d2 75 70 f6 85 83 00 00 00 10 48 8b 45 10 8b 88 08 01 RSP: 0018:ffffae320190ba30 EFLAGS: 00010246 RAX: 00000000b0677d21 RBX: ffff8af1ed9ec000 RCX: 0000000059a9fe49 RDX: 0000000000000000 RSI: 000000000c7e33b7 RDI: ffff8af23daa0af0 RBP: ffff8af1ee11b200 R08: 0000000074fcaf7e R09: 0000000000000000 R10: 0000000000000050 R11: ffffffffb3088680 R12: ffff8af232307f80 R13: 0000000000000003 R14: ffff8af1ed9ec000 R15: 0000000000000000 FS: 00007fe9c6d2f740(0000) GS:ffff8af23da80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fff6772f000 CR3: 00000000746a2004 CR4: 00000000001606e0 Call Trace: tcf_action_exec+0x7c/0x1c0 tcf_classify+0x57/0x160 __dev_queue_xmit+0x3dc/0xd10 ip_finish_output2+0x257/0x6d0 ip_output+0x75/0x280 ip_send_skb+0x15/0x40 raw_sendmsg+0xae3/0x1410 sock_sendmsg+0x36/0x40 __sys_sendto+0x10e/0x140 __x64_sys_sendto+0x24/0x30 do_syscall_64+0x60/0x210 entry_SYSCALL_64_after_hwframe+0x49/0xbe [...] Kernel panic - not syncing: Fatal exception in interrupt Add a TDC selftest to document that 'rate' is now being validated. Reported-by: Matteo Croce <mcroce@redhat.com> Fixes: 5c5670fae430 ("net/sched: Introduce sample tc action") Signed-off-by: Davide Caratti <dcaratti@redhat.com> Acked-by: Yotam Gigi <yotam.gi@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
the control path of 'sample' action does not validate the value of 'rate'
provided by the user, but then it uses it as divisor in the traffic path.
Validate it in tcf_sample_init(), and return -EINVAL with a proper extack
message in case that value is zero, to fix a splat with the script below:

 # tc f a dev test0 egress matchall action sample rate 0 group 1 index 2
 # tc -s a s action sample
 total acts 1

         action order 0: sample rate 1/0 group 1 pipe
          index 2 ref 1 bind 1 installed 19 sec used 19 sec
         Action statistics:
         Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
         backlog 0b 0p requeues 0
 # ping 192.0.2.1 -I test0 -c1 -q

 divide error: 0000 [#1] SMP PTI
 CPU: 1 PID: 6192 Comm: ping Not tainted 5.1.0-rc2.diag2+ #591
 Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
 RIP: 0010:tcf_sample_act+0x9e/0x1e0 [act_sample]
 Code: 6a f1 85 c0 74 0d 80 3d 83 1a 00 00 00 0f 84 9c 00 00 00 4d 85 e4 0f 84 85 00 00 00 e8 9b d7 9c f1 44 8b 8b e0 00 00 00 31 d2 <41> f7 f1 85 d2 75 70 f6 85 83 00 00 00 10 48 8b 45 10 8b 88 08 01
 RSP: 0018:ffffae320190ba30 EFLAGS: 00010246
 RAX: 00000000b0677d21 RBX: ffff8af1ed9ec000 RCX: 0000000059a9fe49
 RDX: 0000000000000000 RSI: 000000000c7e33b7 RDI: ffff8af23daa0af0
 RBP: ffff8af1ee11b200 R08: 0000000074fcaf7e R09: 0000000000000000
 R10: 0000000000000050 R11: ffffffffb3088680 R12: ffff8af232307f80
 R13: 0000000000000003 R14: ffff8af1ed9ec000 R15: 0000000000000000
 FS:  00007fe9c6d2f740(0000) GS:ffff8af23da80000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00007fff6772f000 CR3: 00000000746a2004 CR4: 00000000001606e0
 Call Trace:
  tcf_action_exec+0x7c/0x1c0
  tcf_classify+0x57/0x160
  __dev_queue_xmit+0x3dc/0xd10
  ip_finish_output2+0x257/0x6d0
  ip_output+0x75/0x280
  ip_send_skb+0x15/0x40
  raw_sendmsg+0xae3/0x1410
  sock_sendmsg+0x36/0x40
  __sys_sendto+0x10e/0x140
  __x64_sys_sendto+0x24/0x30
  do_syscall_64+0x60/0x210
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
  [...]
  Kernel panic - not syncing: Fatal exception in interrupt

Add a TDC selftest to document that 'rate' is now being validated.

Reported-by: Matteo Croce <mcroce@redhat.com>
Fixes: 5c5670fae430 ("net/sched: Introduce sample tc action")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Acked-by: Yotam Gigi <yotam.gi@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/sched: act_sample: validate the control action inside init() 2019-03-21T20:26:41+00:00 Davide Caratti dcaratti@redhat.com 2019-03-20T14:00:09+00:00 e8c87c643ef3603c6e63bdecb67b03d794648493 the following script: # tc qdisc add dev crash0 clsact # tc filter add dev crash0 egress matchall \ > action sample rate 1024 group 4 pass index 90 # tc actions replace action sample \ > rate 1024 group 4 goto chain 42 index 90 cookie c1a0c1a0 # tc actions show action sample had the following output: Error: Failed to init TC action chain. We have an error talking to the kernel total acts 1 action order 0: sample rate 1/1024 group 4 goto chain 42 index 90 ref 2 bind 1 cookie c1a0c1a0 Then, the first packet transmitted by crash0 made the kernel crash: BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 #PF error: [normal kernel read fault] PGD 8000000079966067 P4D 8000000079966067 PUD 7987b067 PMD 0 Oops: 0000 [#1] SMP PTI CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.0.0-rc4.gotochain_crash+ #536 Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 Workqueue: ipv6_addrconf addrconf_dad_work RIP: 0010:tcf_action_exec+0xb8/0x100 Code: 00 00 00 20 74 1d 83 f8 03 75 09 49 83 c4 08 4d 39 ec 75 bc 48 83 c4 10 5b 5d 41 5c 41 5d 41 5e 41 5f c3 49 8b 97 a8 00 00 00 <48> 8b 12 48 89 55 00 48 83 c4 10 5b 5d 41 5c 41 5d 41 5e 41 5f c3 RSP: 0018:ffffbee60033fad0 EFLAGS: 00010246 RAX: 000000002000002a RBX: ffff99d7ae6e3b00 RCX: 00000000e555df9b RDX: 0000000000000000 RSI: 00000000b0352718 RDI: ffff99d7fda1fcf0 RBP: ffffbee60033fb70 R08: 0000000070731ab1 R09: 0000000000000400 R10: 0000000000000000 R11: ffff99d7ac733838 R12: ffff99d7f3c2be00 R13: ffff99d7f3c2be08 R14: 0000000000000001 R15: ffff99d7f3c2b600 FS: 0000000000000000(0000) GS:ffff99d7fda00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000000797de006 CR4: 00000000001606f0 Call Trace: tcf_classify+0x58/0x120 __dev_queue_xmit+0x40a/0x890 ? ndisc_next_option+0x50/0x50 ? ___neigh_create+0x4d5/0x680 ? ip6_finish_output2+0x1b5/0x590 ip6_finish_output2+0x1b5/0x590 ? ip6_output+0x68/0x110 ip6_output+0x68/0x110 ? nf_hook.constprop.28+0x79/0xc0 ndisc_send_skb+0x248/0x2e0 ndisc_send_ns+0xf8/0x200 ? addrconf_dad_work+0x389/0x4b0 addrconf_dad_work+0x389/0x4b0 ? __switch_to_asm+0x34/0x70 ? process_one_work+0x195/0x380 ? addrconf_dad_completed+0x370/0x370 process_one_work+0x195/0x380 worker_thread+0x30/0x390 ? process_one_work+0x380/0x380 kthread+0x113/0x130 ? kthread_park+0x90/0x90 ret_from_fork+0x35/0x40 Modules linked in: act_sample psample veth ip6table_filter ip6_tables iptable_filter binfmt_misc ext4 crct10dif_pclmul crc32_pclmul ghash_clmulni_intel mbcache jbd2 snd_hda_codec_generic snd_hda_intel snd_hda_codec snd_hwdep snd_hda_core snd_seq snd_seq_device aesni_intel crypto_simd snd_pcm cryptd glue_helper snd_timer joydev snd pcspkr virtio_balloon i2c_piix4 soundcore nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs ata_generic pata_acpi qxl drm_kms_helper syscopyarea sysfillrect virtio_net sysimgblt fb_sys_fops net_failover ttm failover virtio_blk virtio_console drm ata_piix serio_raw crc32c_intel libata virtio_pci virtio_ring virtio floppy dm_mirror dm_region_hash dm_log dm_mod CR2: 0000000000000000 Validating the control action within tcf_sample_init() proved to fix the above issue. A TDC selftest is added to verify the correct behavior. Fixes: db50514f9a9c ("net: sched: add termination action to allow goto chain") Fixes: 97763dc0f401 ("net_sched: reject unknown tcfa_action values") Signed-off-by: Davide Caratti <dcaratti@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
the following script:

 # tc qdisc add dev crash0 clsact
 # tc filter add dev crash0 egress matchall \
 > action sample rate 1024 group 4 pass index 90
 # tc actions replace action sample \
 > rate 1024 group 4 goto chain 42 index 90 cookie c1a0c1a0
 # tc actions show action sample

had the following output:

 Error: Failed to init TC action chain.
 We have an error talking to the kernel
 total acts 1

         action order 0: sample rate 1/1024 group 4 goto chain 42
          index 90 ref 2 bind 1
         cookie c1a0c1a0

Then, the first packet transmitted by crash0 made the kernel crash:

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
 #PF error: [normal kernel read fault]
 PGD 8000000079966067 P4D 8000000079966067 PUD 7987b067 PMD 0
 Oops: 0000 [#1] SMP PTI
 CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.0.0-rc4.gotochain_crash+ #536
 Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
 Workqueue: ipv6_addrconf addrconf_dad_work
 RIP: 0010:tcf_action_exec+0xb8/0x100
 Code: 00 00 00 20 74 1d 83 f8 03 75 09 49 83 c4 08 4d 39 ec 75 bc 48 83 c4 10 5b 5d 41 5c 41 5d 41 5e 41 5f c3 49 8b 97 a8 00 00 00 <48> 8b 12 48 89 55 00 48 83 c4 10 5b 5d 41 5c 41 5d 41 5e 41 5f c3
 RSP: 0018:ffffbee60033fad0 EFLAGS: 00010246
 RAX: 000000002000002a RBX: ffff99d7ae6e3b00 RCX: 00000000e555df9b
 RDX: 0000000000000000 RSI: 00000000b0352718 RDI: ffff99d7fda1fcf0
 RBP: ffffbee60033fb70 R08: 0000000070731ab1 R09: 0000000000000400
 R10: 0000000000000000 R11: ffff99d7ac733838 R12: ffff99d7f3c2be00
 R13: ffff99d7f3c2be08 R14: 0000000000000001 R15: ffff99d7f3c2b600
 FS:  0000000000000000(0000) GS:ffff99d7fda00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000000 CR3: 00000000797de006 CR4: 00000000001606f0
 Call Trace:
  tcf_classify+0x58/0x120
  __dev_queue_xmit+0x40a/0x890
  ? ndisc_next_option+0x50/0x50
  ? ___neigh_create+0x4d5/0x680
  ? ip6_finish_output2+0x1b5/0x590
  ip6_finish_output2+0x1b5/0x590
  ? ip6_output+0x68/0x110
  ip6_output+0x68/0x110
  ? nf_hook.constprop.28+0x79/0xc0
  ndisc_send_skb+0x248/0x2e0
  ndisc_send_ns+0xf8/0x200
  ? addrconf_dad_work+0x389/0x4b0
  addrconf_dad_work+0x389/0x4b0
  ? __switch_to_asm+0x34/0x70
  ? process_one_work+0x195/0x380
  ? addrconf_dad_completed+0x370/0x370
  process_one_work+0x195/0x380
  worker_thread+0x30/0x390
  ? process_one_work+0x380/0x380
  kthread+0x113/0x130
  ? kthread_park+0x90/0x90
  ret_from_fork+0x35/0x40
 Modules linked in: act_sample psample veth ip6table_filter ip6_tables iptable_filter binfmt_misc ext4 crct10dif_pclmul crc32_pclmul ghash_clmulni_intel mbcache jbd2 snd_hda_codec_generic snd_hda_intel snd_hda_codec snd_hwdep snd_hda_core snd_seq snd_seq_device aesni_intel crypto_simd snd_pcm cryptd glue_helper snd_timer joydev snd pcspkr virtio_balloon i2c_piix4 soundcore nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs ata_generic pata_acpi qxl drm_kms_helper syscopyarea sysfillrect virtio_net sysimgblt fb_sys_fops net_failover ttm failover virtio_blk virtio_console drm ata_piix serio_raw crc32c_intel libata virtio_pci virtio_ring virtio floppy dm_mirror dm_region_hash dm_log dm_mod
 CR2: 0000000000000000

Validating the control action within tcf_sample_init() proved to fix the
above issue. A TDC selftest is added to verify the correct behavior.

Fixes: db50514f9a9c ("net: sched: add termination action to allow goto chain")
Fixes: 97763dc0f401 ("net_sched: reject unknown tcfa_action values")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/sched: prepare TC actions to properly validate the control action 2019-03-21T20:26:41+00:00 Davide Caratti dcaratti@redhat.com 2019-03-20T13:59:59+00:00 85d0966fa57e0ef2d30d913c98ca93674f7a03c9 - pass a pointer to struct tcf_proto in each actions's init() handler, to allow validating the control action, checking whether the chain exists and (eventually) refcounting it. - remove code that validates the control action after a successful call to the action's init() handler, and replace it with a test that forbids addition of actions having 'goto_chain' and NULL goto_chain pointer at the same time. - add tcf_action_check_ctrlact(), that will validate the control action and eventually allocate the action 'goto_chain' within the init() handler. - add tcf_action_set_ctrlact(), that will assign the control action and swap the current 'goto_chain' pointer with the new given one. This disallows 'goto_chain' on actions that don't initialize it properly in their init() handler, i.e. calling tcf_action_check_ctrlact() after successful IDR reservation and then calling tcf_action_set_ctrlact() to assign 'goto_chain' and 'tcf_action' consistently. By doing this, the kernel does not leak anymore refcounts when a valid 'goto chain' handle is replaced in TC actions, causing kmemleak splats like the following one: # tc chain add dev dd0 chain 42 ingress protocol ip flower \ > ip_proto tcp action drop # tc chain add dev dd0 chain 43 ingress protocol ip flower \ > ip_proto udp action drop # tc filter add dev dd0 ingress matchall \ > action gact goto chain 42 index 66 # tc filter replace dev dd0 ingress matchall \ > action gact goto chain 43 index 66 # echo scan >/sys/kernel/debug/kmemleak <...> unreferenced object 0xffff93c0ee09f000 (size 1024): comm "tc", pid 2565, jiffies 4295339808 (age 65.426s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 08 00 06 00 00 00 00 00 00 00 00 00 ................ backtrace: [<000000009b63f92d>] tc_ctl_chain+0x3d2/0x4c0 [<00000000683a8d72>] rtnetlink_rcv_msg+0x263/0x2d0 [<00000000ddd88f8e>] netlink_rcv_skb+0x4a/0x110 [<000000006126a348>] netlink_unicast+0x1a0/0x250 [<00000000b3340877>] netlink_sendmsg+0x2c1/0x3c0 [<00000000a25a2171>] sock_sendmsg+0x36/0x40 [<00000000f19ee1ec>] ___sys_sendmsg+0x280/0x2f0 [<00000000d0422042>] __sys_sendmsg+0x5e/0xa0 [<000000007a6c61f9>] do_syscall_64+0x5b/0x180 [<00000000ccd07542>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [<0000000013eaa334>] 0xffffffffffffffff Fixes: db50514f9a9c ("net: sched: add termination action to allow goto chain") Fixes: 97763dc0f401 ("net_sched: reject unknown tcfa_action values") Signed-off-by: Davide Caratti <dcaratti@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
- pass a pointer to struct tcf_proto in each actions's init() handler,
  to allow validating the control action, checking whether the chain
  exists and (eventually) refcounting it.
- remove code that validates the control action after a successful call
  to the action's init() handler, and replace it with a test that forbids
  addition of actions having 'goto_chain' and NULL goto_chain pointer at
  the same time.
- add tcf_action_check_ctrlact(), that will validate the control action
  and eventually allocate the action 'goto_chain' within the init()
  handler.
- add tcf_action_set_ctrlact(), that will assign the control action and
  swap the current 'goto_chain' pointer with the new given one.

This disallows 'goto_chain' on actions that don't initialize it properly
in their init() handler, i.e. calling tcf_action_check_ctrlact() after
successful IDR reservation and then calling tcf_action_set_ctrlact()
to assign 'goto_chain' and 'tcf_action' consistently.

By doing this, the kernel does not leak anymore refcounts when a valid
'goto chain' handle is replaced in TC actions, causing kmemleak splats
like the following one:

 # tc chain add dev dd0 chain 42 ingress protocol ip flower \
 > ip_proto tcp action drop
 # tc chain add dev dd0 chain 43 ingress protocol ip flower \
 > ip_proto udp action drop
 # tc filter add dev dd0 ingress matchall \
 > action gact goto chain 42 index 66
 # tc filter replace dev dd0 ingress matchall \
 > action gact goto chain 43 index 66
 # echo scan >/sys/kernel/debug/kmemleak
 <...>
 unreferenced object 0xffff93c0ee09f000 (size 1024):
 comm "tc", pid 2565, jiffies 4295339808 (age 65.426s)
 hex dump (first 32 bytes):
   00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
   00 00 00 00 08 00 06 00 00 00 00 00 00 00 00 00  ................
 backtrace:
   [<000000009b63f92d>] tc_ctl_chain+0x3d2/0x4c0
   [<00000000683a8d72>] rtnetlink_rcv_msg+0x263/0x2d0
   [<00000000ddd88f8e>] netlink_rcv_skb+0x4a/0x110
   [<000000006126a348>] netlink_unicast+0x1a0/0x250
   [<00000000b3340877>] netlink_sendmsg+0x2c1/0x3c0
   [<00000000a25a2171>] sock_sendmsg+0x36/0x40
   [<00000000f19ee1ec>] ___sys_sendmsg+0x280/0x2f0
   [<00000000d0422042>] __sys_sendmsg+0x5e/0xa0
   [<000000007a6c61f9>] do_syscall_64+0x5b/0x180
   [<00000000ccd07542>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
   [<0000000013eaa334>] 0xffffffffffffffff

Fixes: db50514f9a9c ("net: sched: add termination action to allow goto chain")
Fixes: 97763dc0f401 ("net_sched: reject unknown tcfa_action values")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net: Change TCA_ACT_* to TCA_ID_* to match that of TCA_ID_POLICE 2019-02-10T17:28:43+00:00 Eli Cohen eli@mellanox.com 2019-02-10T12:25:00+00:00 eddd2cf195d6fb5e4bbc91a0fe4be55110f559ab Modify the kernel users of the TCA_ACT_* macros to use TCA_ID_*. For example, use TCA_ID_GACT instead of TCA_ACT_GACT. This will align with TCA_ID_POLICE and also differentiates these identifier, used in struct tc_action_ops type field, from other macros starting with TCA_ACT_. To make things clearer, we name the enum defining the TCA_ID_* identifiers and also change the "type" field of struct tc_action to id. Signed-off-by: Eli Cohen <eli@mellanox.com> Acked-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
Modify the kernel users of the TCA_ACT_* macros to use TCA_ID_*. For
example, use TCA_ID_GACT instead of TCA_ACT_GACT. This will align with
TCA_ID_POLICE and also differentiates these identifier, used in struct
tc_action_ops type field, from other macros starting with TCA_ACT_.

To make things clearer, we name the enum defining the TCA_ID_*
identifiers and also change the "type" field of struct tc_action to
id.

Signed-off-by: Eli Cohen <eli@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Merge ra.kernel.org:/pub/scm/linux/kernel/git/davem/net 2018-09-18T16:33:27+00:00 David S. Miller davem@davemloft.net 2018-09-18T16:33:27+00:00 e366fa435032db1ce1538a2c029714666985dd48 Two new tls tests added in parallel in both net and net-next. Used Stephen Rothwell's linux-next resolution. Signed-off-by: David S. Miller <davem@davemloft.net> 
Two new tls tests added in parallel in both net and net-next.

Used Stephen Rothwell's linux-next resolution.

Signed-off-by: David S. Miller <davem@davemloft.net>
net/sched: act_sample: fix NULL dereference in the data path 2018-09-14T15:46:28+00:00 Davide Caratti dcaratti@redhat.com 2018-09-14T10:03:18+00:00 34043d250f51368f214aed7f54c2dc29c819a8c7 Matteo reported the following splat, testing the datapath of TC 'sample': BUG: KASAN: null-ptr-deref in tcf_sample_act+0xc4/0x310 Read of size 8 at addr 0000000000000000 by task nc/433 CPU: 0 PID: 433 Comm: nc Not tainted 4.19.0-rc3-kvm #17 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS ?-20180531_142017-buildhw-08.phx2.fedoraproject.org-1.fc28 04/01/2014 Call Trace: kasan_report.cold.6+0x6c/0x2fa tcf_sample_act+0xc4/0x310 ? dev_hard_start_xmit+0x117/0x180 tcf_action_exec+0xa3/0x160 tcf_classify+0xdd/0x1d0 htb_enqueue+0x18e/0x6b0 ? deref_stack_reg+0x7a/0xb0 ? htb_delete+0x4b0/0x4b0 ? unwind_next_frame+0x819/0x8f0 ? entry_SYSCALL_64_after_hwframe+0x44/0xa9 __dev_queue_xmit+0x722/0xca0 ? unwind_get_return_address_ptr+0x50/0x50 ? netdev_pick_tx+0xe0/0xe0 ? save_stack+0x8c/0xb0 ? kasan_kmalloc+0xbe/0xd0 ? __kmalloc_track_caller+0xe4/0x1c0 ? __kmalloc_reserve.isra.45+0x24/0x70 ? __alloc_skb+0xdd/0x2e0 ? sk_stream_alloc_skb+0x91/0x3b0 ? tcp_sendmsg_locked+0x71b/0x15a0 ? tcp_sendmsg+0x22/0x40 ? __sys_sendto+0x1b0/0x250 ? __x64_sys_sendto+0x6f/0x80 ? do_syscall_64+0x5d/0x150 ? entry_SYSCALL_64_after_hwframe+0x44/0xa9 ? __sys_sendto+0x1b0/0x250 ? __x64_sys_sendto+0x6f/0x80 ? do_syscall_64+0x5d/0x150 ? entry_SYSCALL_64_after_hwframe+0x44/0xa9 ip_finish_output2+0x495/0x590 ? ip_copy_metadata+0x2e0/0x2e0 ? skb_gso_validate_network_len+0x6f/0x110 ? ip_finish_output+0x174/0x280 __tcp_transmit_skb+0xb17/0x12b0 ? __tcp_select_window+0x380/0x380 tcp_write_xmit+0x913/0x1de0 ? __sk_mem_schedule+0x50/0x80 tcp_sendmsg_locked+0x49d/0x15a0 ? tcp_rcv_established+0x8da/0xa30 ? tcp_set_state+0x220/0x220 ? clear_user+0x1f/0x50 ? iov_iter_zero+0x1ae/0x590 ? __fget_light+0xa0/0xe0 tcp_sendmsg+0x22/0x40 __sys_sendto+0x1b0/0x250 ? __ia32_sys_getpeername+0x40/0x40 ? _copy_to_user+0x58/0x70 ? poll_select_copy_remaining+0x176/0x200 ? __pollwait+0x1c0/0x1c0 ? ktime_get_ts64+0x11f/0x140 ? kern_select+0x108/0x150 ? core_sys_select+0x360/0x360 ? vfs_read+0x127/0x150 ? kernel_write+0x90/0x90 __x64_sys_sendto+0x6f/0x80 do_syscall_64+0x5d/0x150 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fefef2b129d Code: ff ff ff ff eb b6 0f 1f 80 00 00 00 00 48 8d 05 51 37 0c 00 41 89 ca 8b 00 85 c0 75 20 45 31 c9 45 31 c0 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 6b f3 c3 66 0f 1f 84 00 00 00 00 00 41 56 41 RSP: 002b:00007fff2f5350c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 000056118d60c120 RCX: 00007fefef2b129d RDX: 0000000000002000 RSI: 000056118d629320 RDI: 0000000000000003 RBP: 000056118d530370 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000002000 R13: 000056118d5c2a10 R14: 000056118d5c2a10 R15: 000056118d5303b8 tcf_sample_act() tried to update its per-cpu stats, but tcf_sample_init() forgot to allocate them, because tcf_idr_create() was called with a wrong value of 'cpustats'. Setting it to true proved to fix the reported crash. Reported-by: Matteo Croce <mcroce@redhat.com> Fixes: 65a206c01e8e ("net/sched: Change act_api and act_xxx modules to use IDR") Fixes: 5c5670fae430 ("net/sched: Introduce sample tc action") Tested-by: Matteo Croce <mcroce@redhat.com> Signed-off-by: Davide Caratti <dcaratti@redhat.com> Acked-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
Matteo reported the following splat, testing the datapath of TC 'sample':

 BUG: KASAN: null-ptr-deref in tcf_sample_act+0xc4/0x310
 Read of size 8 at addr 0000000000000000 by task nc/433

 CPU: 0 PID: 433 Comm: nc Not tainted 4.19.0-rc3-kvm #17
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS ?-20180531_142017-buildhw-08.phx2.fedoraproject.org-1.fc28 04/01/2014
 Call Trace:
  kasan_report.cold.6+0x6c/0x2fa
  tcf_sample_act+0xc4/0x310
  ? dev_hard_start_xmit+0x117/0x180
  tcf_action_exec+0xa3/0x160
  tcf_classify+0xdd/0x1d0
  htb_enqueue+0x18e/0x6b0
  ? deref_stack_reg+0x7a/0xb0
  ? htb_delete+0x4b0/0x4b0
  ? unwind_next_frame+0x819/0x8f0
  ? entry_SYSCALL_64_after_hwframe+0x44/0xa9
  __dev_queue_xmit+0x722/0xca0
  ? unwind_get_return_address_ptr+0x50/0x50
  ? netdev_pick_tx+0xe0/0xe0
  ? save_stack+0x8c/0xb0
  ? kasan_kmalloc+0xbe/0xd0
  ? __kmalloc_track_caller+0xe4/0x1c0
  ? __kmalloc_reserve.isra.45+0x24/0x70
  ? __alloc_skb+0xdd/0x2e0
  ? sk_stream_alloc_skb+0x91/0x3b0
  ? tcp_sendmsg_locked+0x71b/0x15a0
  ? tcp_sendmsg+0x22/0x40
  ? __sys_sendto+0x1b0/0x250
  ? __x64_sys_sendto+0x6f/0x80
  ? do_syscall_64+0x5d/0x150
  ? entry_SYSCALL_64_after_hwframe+0x44/0xa9
  ? __sys_sendto+0x1b0/0x250
  ? __x64_sys_sendto+0x6f/0x80
  ? do_syscall_64+0x5d/0x150
  ? entry_SYSCALL_64_after_hwframe+0x44/0xa9
  ip_finish_output2+0x495/0x590
  ? ip_copy_metadata+0x2e0/0x2e0
  ? skb_gso_validate_network_len+0x6f/0x110
  ? ip_finish_output+0x174/0x280
  __tcp_transmit_skb+0xb17/0x12b0
  ? __tcp_select_window+0x380/0x380
  tcp_write_xmit+0x913/0x1de0
  ? __sk_mem_schedule+0x50/0x80
  tcp_sendmsg_locked+0x49d/0x15a0
  ? tcp_rcv_established+0x8da/0xa30
  ? tcp_set_state+0x220/0x220
  ? clear_user+0x1f/0x50
  ? iov_iter_zero+0x1ae/0x590
  ? __fget_light+0xa0/0xe0
  tcp_sendmsg+0x22/0x40
  __sys_sendto+0x1b0/0x250
  ? __ia32_sys_getpeername+0x40/0x40
  ? _copy_to_user+0x58/0x70
  ? poll_select_copy_remaining+0x176/0x200
  ? __pollwait+0x1c0/0x1c0
  ? ktime_get_ts64+0x11f/0x140
  ? kern_select+0x108/0x150
  ? core_sys_select+0x360/0x360
  ? vfs_read+0x127/0x150
  ? kernel_write+0x90/0x90
  __x64_sys_sendto+0x6f/0x80
  do_syscall_64+0x5d/0x150
  entry_SYSCALL_64_after_hwframe+0x44/0xa9
 RIP: 0033:0x7fefef2b129d
 Code: ff ff ff ff eb b6 0f 1f 80 00 00 00 00 48 8d 05 51 37 0c 00 41 89 ca 8b 00 85 c0 75 20 45 31 c9 45 31 c0 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 6b f3 c3 66 0f 1f 84 00 00 00 00 00 41 56 41
 RSP: 002b:00007fff2f5350c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
 RAX: ffffffffffffffda RBX: 000056118d60c120 RCX: 00007fefef2b129d
 RDX: 0000000000002000 RSI: 000056118d629320 RDI: 0000000000000003
 RBP: 000056118d530370 R08: 0000000000000000 R09: 0000000000000000
 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000002000
 R13: 000056118d5c2a10 R14: 000056118d5c2a10 R15: 000056118d5303b8

tcf_sample_act() tried to update its per-cpu stats, but tcf_sample_init()
forgot to allocate them, because tcf_idr_create() was called with a wrong
value of 'cpustats'. Setting it to true proved to fix the reported crash.

Reported-by: Matteo Croce <mcroce@redhat.com>
Fixes: 65a206c01e8e ("net/sched: Change act_api and act_xxx modules to use IDR")
Fixes: 5c5670fae430 ("net/sched: Introduce sample tc action")
Tested-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Revert "net: sched: act: add extack for lookup callback" 2018-09-01T05:50:15+00:00 Cong Wang xiyou.wangcong@gmail.com 2018-08-29T17:15:35+00:00 f061b48c1787e6fece2190e27da6878f4f1796d0 This reverts commit 331a9295de23 ("net: sched: act: add extack for lookup callback"). This extack is never used after 6 months... In fact, it can be just set in the caller, right after ->lookup(). Cc: Alexander Aring <aring@mojatatu.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
This reverts commit 331a9295de23 ("net: sched: act: add extack for lookup callback").

This extack is never used after 6 months... In fact, it can be just
set in the caller, right after ->lookup().

Cc: Alexander Aring <aring@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net_sched: remove unnecessary ops->delete() 2018-08-21T19:45:44+00:00 Cong Wang xiyou.wangcong@gmail.com 2018-08-19T19:22:06+00:00 97a3f84f2c84f81b859aedd2c186df09c2ee21a6 All ops->delete() wants is getting the tn->idrinfo, but we already have tc_action before calling ops->delete(), and tc_action has a pointer ->idrinfo. More importantly, each type of action does the same thing, that is, just calling tcf_idr_delete_index(). So it can be just removed. Fixes: b409074e6693 ("net: sched: add 'delete' function to action ops") Cc: Jiri Pirko <jiri@mellanox.com> Cc: Vlad Buslov <vladbu@mellanox.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
All ops->delete() wants is getting the tn->idrinfo, but we already
have tc_action before calling ops->delete(), and tc_action has
a pointer ->idrinfo.

More importantly, each type of action does the same thing, that is,
just calling tcf_idr_delete_index().

So it can be just removed.

Fixes: b409074e6693 ("net: sched: add 'delete' function to action ops")
Cc: Jiri Pirko <jiri@mellanox.com>
Cc: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net: sched: always disable bh when taking tcf_lock 2018-08-19T17:46:21+00:00 Vlad Buslov vladbu@mellanox.com 2018-08-14T18:46:16+00:00 653cd284a8a857ddfcf24f5bc3bd204a229f6c9f Recently, ops->init() and ops->dump() of all actions were modified to always obtain tcf_lock when accessing private action state. Actions that don't depend on tcf_lock for synchronization with their data path use non-bh locking API. However, tcf_lock is also used to protect rate estimator stats in softirq context by timer callback. Change ops->init() and ops->dump() of all actions to disable bh when using tcf_lock to prevent deadlock reported by following lockdep warning: [ 105.470398] ================================ [ 105.475014] WARNING: inconsistent lock state [ 105.479628] 4.18.0-rc8+ #664 Not tainted [ 105.483897] -------------------------------- [ 105.488511] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. [ 105.494871] swapper/16/0 [HC0[0]:SC1[1]:HE1:SE0] takes: [ 105.500449] 00000000f86c012e (&(&p->tcfa_lock)->rlock){+.?.}, at: est_fetch_counters+0x3c/0xa0 [ 105.509696] {SOFTIRQ-ON-W} state was registered at: [ 105.514925] _raw_spin_lock+0x2c/0x40 [ 105.519022] tcf_bpf_init+0x579/0x820 [act_bpf] [ 105.523990] tcf_action_init_1+0x4e4/0x660 [ 105.528518] tcf_action_init+0x1ce/0x2d0 [ 105.532880] tcf_exts_validate+0x1d8/0x200 [ 105.537416] fl_change+0x55a/0x268b [cls_flower] [ 105.542469] tc_new_tfilter+0x748/0xa20 [ 105.546738] rtnetlink_rcv_msg+0x56a/0x6d0 [ 105.551268] netlink_rcv_skb+0x18d/0x200 [ 105.555628] netlink_unicast+0x2d0/0x370 [ 105.559990] netlink_sendmsg+0x3b9/0x6a0 [ 105.564349] sock_sendmsg+0x6b/0x80 [ 105.568271] ___sys_sendmsg+0x4a1/0x520 [ 105.572547] __sys_sendmsg+0xd7/0x150 [ 105.576655] do_syscall_64+0x72/0x2c0 [ 105.580757] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 105.586243] irq event stamp: 489296 [ 105.590084] hardirqs last enabled at (489296): [<ffffffffb507e639>] _raw_spin_unlock_irq+0x29/0x40 [ 105.599765] hardirqs last disabled at (489295): [<ffffffffb507e745>] _raw_spin_lock_irq+0x15/0x50 [ 105.609277] softirqs last enabled at (489292): [<ffffffffb413a6a3>] irq_enter+0x83/0xa0 [ 105.618001] softirqs last disabled at (489293): [<ffffffffb413a800>] irq_exit+0x140/0x190 [ 105.626813] other info that might help us debug this: [ 105.633976] Possible unsafe locking scenario: [ 105.640526] CPU0 [ 105.643325] ---- [ 105.646125] lock(&(&p->tcfa_lock)->rlock); [ 105.650747] <Interrupt> [ 105.653717] lock(&(&p->tcfa_lock)->rlock); [ 105.658514] *** DEADLOCK *** [ 105.665349] 1 lock held by swapper/16/0: [ 105.669629] #0: 00000000a640ad99 ((&est->timer)){+.-.}, at: call_timer_fn+0x10b/0x550 [ 105.678200] stack backtrace: [ 105.683194] CPU: 16 PID: 0 Comm: swapper/16 Not tainted 4.18.0-rc8+ #664 [ 105.690249] Hardware name: Supermicro SYS-2028TP-DECR/X10DRT-P, BIOS 2.0b 03/30/2017 [ 105.698626] Call Trace: [ 105.701421] <IRQ> [ 105.703791] dump_stack+0x92/0xeb [ 105.707461] print_usage_bug+0x336/0x34c [ 105.711744] mark_lock+0x7c9/0x980 [ 105.715500] ? print_shortest_lock_dependencies+0x2e0/0x2e0 [ 105.721424] ? check_usage_forwards+0x230/0x230 [ 105.726315] __lock_acquire+0x923/0x26f0 [ 105.730597] ? debug_show_all_locks+0x240/0x240 [ 105.735478] ? mark_lock+0x493/0x980 [ 105.739412] ? check_chain_key+0x140/0x1f0 [ 105.743861] ? __lock_acquire+0x836/0x26f0 [ 105.748323] ? lock_acquire+0x12e/0x290 [ 105.752516] lock_acquire+0x12e/0x290 [ 105.756539] ? est_fetch_counters+0x3c/0xa0 [ 105.761084] _raw_spin_lock+0x2c/0x40 [ 105.765099] ? est_fetch_counters+0x3c/0xa0 [ 105.769633] est_fetch_counters+0x3c/0xa0 [ 105.773995] est_timer+0x87/0x390 [ 105.777670] ? est_fetch_counters+0xa0/0xa0 [ 105.782210] ? lock_acquire+0x12e/0x290 [ 105.786410] call_timer_fn+0x161/0x550 [ 105.790512] ? est_fetch_counters+0xa0/0xa0 [ 105.795055] ? del_timer_sync+0xd0/0xd0 [ 105.799249] ? __lock_is_held+0x93/0x110 [ 105.803531] ? mark_held_locks+0x20/0xe0 [ 105.807813] ? _raw_spin_unlock_irq+0x29/0x40 [ 105.812525] ? est_fetch_counters+0xa0/0xa0 [ 105.817069] ? est_fetch_counters+0xa0/0xa0 [ 105.821610] run_timer_softirq+0x3c4/0x9f0 [ 105.826064] ? lock_acquire+0x12e/0x290 [ 105.830257] ? __bpf_trace_timer_class+0x10/0x10 [ 105.835237] ? __lock_is_held+0x25/0x110 [ 105.839517] __do_softirq+0x11d/0x7bf [ 105.843542] irq_exit+0x140/0x190 [ 105.847208] smp_apic_timer_interrupt+0xac/0x3b0 [ 105.852182] apic_timer_interrupt+0xf/0x20 [ 105.856628] </IRQ> [ 105.859081] RIP: 0010:cpuidle_enter_state+0xd8/0x4d0 [ 105.864395] Code: 46 ff 48 89 44 24 08 0f 1f 44 00 00 31 ff e8 cf ec 46 ff 80 7c 24 07 00 0f 85 1d 02 00 00 e8 9f 90 4b ff fb 66 0f 1f 44 00 00 <4c> 8b 6c 24 08 4d 29 fd 0f 80 36 03 00 00 4c 89 e8 48 ba cf f7 53 [ 105.884288] RSP: 0018:ffff8803ad94fd20 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 [ 105.892494] RAX: 0000000000000000 RBX: ffffe8fb300829c0 RCX: ffffffffb41e19e1 [ 105.899988] RDX: 0000000000000007 RSI: dffffc0000000000 RDI: ffff8803ad9358ac [ 105.907503] RBP: ffffffffb6636300 R08: 0000000000000004 R09: 0000000000000000 [ 105.914997] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000004 [ 105.922487] R13: ffffffffb6636140 R14: ffffffffb66362d8 R15: 000000188d36091b [ 105.929988] ? trace_hardirqs_on_caller+0x141/0x2d0 [ 105.935232] do_idle+0x28e/0x320 [ 105.938817] ? arch_cpu_idle_exit+0x40/0x40 [ 105.943361] ? mark_lock+0x8c1/0x980 [ 105.947295] ? _raw_spin_unlock_irqrestore+0x32/0x60 [ 105.952619] cpu_startup_entry+0xc2/0xd0 [ 105.956900] ? cpu_in_idle+0x20/0x20 [ 105.960830] ? _raw_spin_unlock_irqrestore+0x32/0x60 [ 105.966146] ? trace_hardirqs_on_caller+0x141/0x2d0 [ 105.971391] start_secondary+0x2b5/0x360 [ 105.975669] ? set_cpu_sibling_map+0x1330/0x1330 [ 105.980654] secondary_startup_64+0xa5/0xb0 Taking tcf_lock in sample action with bh disabled causes lockdep to issue a warning regarding possible irq lock inversion dependency between tcf_lock, and psample_groups_lock that is taken when holding tcf_lock in sample init: [ 162.108959] Possible interrupt unsafe locking scenario: [ 162.116386] CPU0 CPU1 [ 162.121277] ---- ---- [ 162.126162] lock(psample_groups_lock); [ 162.130447] local_irq_disable(); [ 162.136772] lock(&(&p->tcfa_lock)->rlock); [ 162.143957] lock(psample_groups_lock); [ 162.150813] <Interrupt> [ 162.153808] lock(&(&p->tcfa_lock)->rlock); [ 162.158608] *** DEADLOCK *** In order to prevent potential lock inversion dependency between tcf_lock and psample_groups_lock, extract call to psample_group_get() from tcf_lock protected section in sample action init function. Fixes: 4e232818bd32 ("net: sched: act_mirred: remove dependency on rtnl lock") Fixes: 764e9a24480f ("net: sched: act_vlan: remove dependency on rtnl lock") Fixes: 729e01260989 ("net: sched: act_tunnel_key: remove dependency on rtnl lock") Fixes: d77284956656 ("net: sched: act_sample: remove dependency on rtnl lock") Fixes: e8917f437006 ("net: sched: act_gact: remove dependency on rtnl lock") Fixes: b6a2b971c0b0 ("net: sched: act_csum: remove dependency on rtnl lock") Fixes: 2142236b4584 ("net: sched: act_bpf: remove dependency on rtnl lock") Signed-off-by: Vlad Buslov <vladbu@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
Recently, ops->init() and ops->dump() of all actions were modified to
always obtain tcf_lock when accessing private action state. Actions that
don't depend on tcf_lock for synchronization with their data path use
non-bh locking API. However, tcf_lock is also used to protect rate
estimator stats in softirq context by timer callback.

Change ops->init() and ops->dump() of all actions to disable bh when using
tcf_lock to prevent deadlock reported by following lockdep warning:

[  105.470398] ================================
[  105.475014] WARNING: inconsistent lock state
[  105.479628] 4.18.0-rc8+ #664 Not tainted
[  105.483897] --------------------------------
[  105.488511] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
[  105.494871] swapper/16/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
[  105.500449] 00000000f86c012e (&(&p->tcfa_lock)->rlock){+.?.}, at: est_fetch_counters+0x3c/0xa0
[  105.509696] {SOFTIRQ-ON-W} state was registered at:
[  105.514925]   _raw_spin_lock+0x2c/0x40
[  105.519022]   tcf_bpf_init+0x579/0x820 [act_bpf]
[  105.523990]   tcf_action_init_1+0x4e4/0x660
[  105.528518]   tcf_action_init+0x1ce/0x2d0
[  105.532880]   tcf_exts_validate+0x1d8/0x200
[  105.537416]   fl_change+0x55a/0x268b [cls_flower]
[  105.542469]   tc_new_tfilter+0x748/0xa20
[  105.546738]   rtnetlink_rcv_msg+0x56a/0x6d0
[  105.551268]   netlink_rcv_skb+0x18d/0x200
[  105.555628]   netlink_unicast+0x2d0/0x370
[  105.559990]   netlink_sendmsg+0x3b9/0x6a0
[  105.564349]   sock_sendmsg+0x6b/0x80
[  105.568271]   ___sys_sendmsg+0x4a1/0x520
[  105.572547]   __sys_sendmsg+0xd7/0x150
[  105.576655]   do_syscall_64+0x72/0x2c0
[  105.580757]   entry_SYSCALL_64_after_hwframe+0x49/0xbe
[  105.586243] irq event stamp: 489296
[  105.590084] hardirqs last  enabled at (489296): [<ffffffffb507e639>] _raw_spin_unlock_irq+0x29/0x40
[  105.599765] hardirqs last disabled at (489295): [<ffffffffb507e745>] _raw_spin_lock_irq+0x15/0x50
[  105.609277] softirqs last  enabled at (489292): [<ffffffffb413a6a3>] irq_enter+0x83/0xa0
[  105.618001] softirqs last disabled at (489293): [<ffffffffb413a800>] irq_exit+0x140/0x190
[  105.626813]
               other info that might help us debug this:
[  105.633976]  Possible unsafe locking scenario:

[  105.640526]        CPU0
[  105.643325]        ----
[  105.646125]   lock(&(&p->tcfa_lock)->rlock);
[  105.650747]   <Interrupt>
[  105.653717]     lock(&(&p->tcfa_lock)->rlock);
[  105.658514]
                *** DEADLOCK ***

[  105.665349] 1 lock held by swapper/16/0:
[  105.669629]  #0: 00000000a640ad99 ((&est->timer)){+.-.}, at: call_timer_fn+0x10b/0x550
[  105.678200]
               stack backtrace:
[  105.683194] CPU: 16 PID: 0 Comm: swapper/16 Not tainted 4.18.0-rc8+ #664
[  105.690249] Hardware name: Supermicro SYS-2028TP-DECR/X10DRT-P, BIOS 2.0b 03/30/2017
[  105.698626] Call Trace:
[  105.701421]  <IRQ>
[  105.703791]  dump_stack+0x92/0xeb
[  105.707461]  print_usage_bug+0x336/0x34c
[  105.711744]  mark_lock+0x7c9/0x980
[  105.715500]  ? print_shortest_lock_dependencies+0x2e0/0x2e0
[  105.721424]  ? check_usage_forwards+0x230/0x230
[  105.726315]  __lock_acquire+0x923/0x26f0
[  105.730597]  ? debug_show_all_locks+0x240/0x240
[  105.735478]  ? mark_lock+0x493/0x980
[  105.739412]  ? check_chain_key+0x140/0x1f0
[  105.743861]  ? __lock_acquire+0x836/0x26f0
[  105.748323]  ? lock_acquire+0x12e/0x290
[  105.752516]  lock_acquire+0x12e/0x290
[  105.756539]  ? est_fetch_counters+0x3c/0xa0
[  105.761084]  _raw_spin_lock+0x2c/0x40
[  105.765099]  ? est_fetch_counters+0x3c/0xa0
[  105.769633]  est_fetch_counters+0x3c/0xa0
[  105.773995]  est_timer+0x87/0x390
[  105.777670]  ? est_fetch_counters+0xa0/0xa0
[  105.782210]  ? lock_acquire+0x12e/0x290
[  105.786410]  call_timer_fn+0x161/0x550
[  105.790512]  ? est_fetch_counters+0xa0/0xa0
[  105.795055]  ? del_timer_sync+0xd0/0xd0
[  105.799249]  ? __lock_is_held+0x93/0x110
[  105.803531]  ? mark_held_locks+0x20/0xe0
[  105.807813]  ? _raw_spin_unlock_irq+0x29/0x40
[  105.812525]  ? est_fetch_counters+0xa0/0xa0
[  105.817069]  ? est_fetch_counters+0xa0/0xa0
[  105.821610]  run_timer_softirq+0x3c4/0x9f0
[  105.826064]  ? lock_acquire+0x12e/0x290
[  105.830257]  ? __bpf_trace_timer_class+0x10/0x10
[  105.835237]  ? __lock_is_held+0x25/0x110
[  105.839517]  __do_softirq+0x11d/0x7bf
[  105.843542]  irq_exit+0x140/0x190
[  105.847208]  smp_apic_timer_interrupt+0xac/0x3b0
[  105.852182]  apic_timer_interrupt+0xf/0x20
[  105.856628]  </IRQ>
[  105.859081] RIP: 0010:cpuidle_enter_state+0xd8/0x4d0
[  105.864395] Code: 46 ff 48 89 44 24 08 0f 1f 44 00 00 31 ff e8 cf ec 46 ff 80 7c 24 07 00 0f 85 1d 02 00 00 e8 9f 90 4b ff fb 66 0f 1f 44 00 00 <4c> 8b 6c 24 08 4d 29 fd 0f 80 36 03 00 00 4c 89 e8 48 ba cf f7 53
[  105.884288] RSP: 0018:ffff8803ad94fd20 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
[  105.892494] RAX: 0000000000000000 RBX: ffffe8fb300829c0 RCX: ffffffffb41e19e1
[  105.899988] RDX: 0000000000000007 RSI: dffffc0000000000 RDI: ffff8803ad9358ac
[  105.907503] RBP: ffffffffb6636300 R08: 0000000000000004 R09: 0000000000000000
[  105.914997] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000004
[  105.922487] R13: ffffffffb6636140 R14: ffffffffb66362d8 R15: 000000188d36091b
[  105.929988]  ? trace_hardirqs_on_caller+0x141/0x2d0
[  105.935232]  do_idle+0x28e/0x320
[  105.938817]  ? arch_cpu_idle_exit+0x40/0x40
[  105.943361]  ? mark_lock+0x8c1/0x980
[  105.947295]  ? _raw_spin_unlock_irqrestore+0x32/0x60
[  105.952619]  cpu_startup_entry+0xc2/0xd0
[  105.956900]  ? cpu_in_idle+0x20/0x20
[  105.960830]  ? _raw_spin_unlock_irqrestore+0x32/0x60
[  105.966146]  ? trace_hardirqs_on_caller+0x141/0x2d0
[  105.971391]  start_secondary+0x2b5/0x360
[  105.975669]  ? set_cpu_sibling_map+0x1330/0x1330
[  105.980654]  secondary_startup_64+0xa5/0xb0

Taking tcf_lock in sample action with bh disabled causes lockdep to issue a
warning regarding possible irq lock inversion dependency between tcf_lock,
and psample_groups_lock that is taken when holding tcf_lock in sample init:

[  162.108959]  Possible interrupt unsafe locking scenario:

[  162.116386]        CPU0                    CPU1
[  162.121277]        ----                    ----
[  162.126162]   lock(psample_groups_lock);
[  162.130447]                                local_irq_disable();
[  162.136772]                                lock(&(&p->tcfa_lock)->rlock);
[  162.143957]                                lock(psample_groups_lock);
[  162.150813]   <Interrupt>
[  162.153808]     lock(&(&p->tcfa_lock)->rlock);
[  162.158608]
                *** DEADLOCK ***

In order to prevent potential lock inversion dependency between tcf_lock
and psample_groups_lock, extract call to psample_group_get() from tcf_lock
protected section in sample action init function.

Fixes: 4e232818bd32 ("net: sched: act_mirred: remove dependency on rtnl lock")
Fixes: 764e9a24480f ("net: sched: act_vlan: remove dependency on rtnl lock")
Fixes: 729e01260989 ("net: sched: act_tunnel_key: remove dependency on rtnl lock")
Fixes: d77284956656 ("net: sched: act_sample: remove dependency on rtnl lock")
Fixes: e8917f437006 ("net: sched: act_gact: remove dependency on rtnl lock")
Fixes: b6a2b971c0b0 ("net: sched: act_csum: remove dependency on rtnl lock")
Fixes: 2142236b4584 ("net: sched: act_bpf: remove dependency on rtnl lock")
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net: sched: act_sample: remove dependency on rtnl lock 2018-08-11T19:37:09+00:00 Vlad Buslov vladbu@mellanox.com 2018-08-10T17:51:47+00:00 d7728495665601658c7f94f3b5fa4e3f54d71c18 Use tcf spinlock to protect private sample action data from concurrent modification during dump and init. Signed-off-by: Vlad Buslov <vladbu@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
Use tcf spinlock to protect private sample action data from concurrent
modification during dump and init.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>