net/sched: fq_pie: initialize timer earlier in fq_pie_init()
authorDavide Caratti <dcaratti@redhat.com>
Thu, 3 Dec 2020 18:40:47 +0000 (19:40 +0100)
committerJakub Kicinski <kuba@kernel.org>
Fri, 4 Dec 2020 22:15:01 +0000 (14:15 -0800)
commit4eef8b1f36f2ff06966b8f7c2143ef0c447877de
treea926f31a27f079736695f0861f34cfde391881da
parenta1cdfbe8f0fb2ada84fcc3dbb5ff8fdf288a99b6
net/sched: fq_pie: initialize timer earlier in fq_pie_init()

with the following tdc testcase:

 83be: (qdisc, fq_pie) Create FQ-PIE with invalid number of flows

as fq_pie_init() fails, fq_pie_destroy() is called to clean up. Since the
timer is not yet initialized, it's possible to observe a splat like this:

  INFO: trying to register non-static key.
  the code is fine but needs lockdep annotation.
  turning off the locking correctness validator.
  CPU: 0 PID: 975 Comm: tc Not tainted 5.10.0-rc4+ #298
  Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014
  Call Trace:
   dump_stack+0x99/0xcb
   register_lock_class+0x12dd/0x1750
   __lock_acquire+0xfe/0x3970
   lock_acquire+0x1c8/0x7f0
   del_timer_sync+0x49/0xd0
   fq_pie_destroy+0x3f/0x80 [sch_fq_pie]
   qdisc_create+0x916/0x1160
   tc_modify_qdisc+0x3c4/0x1630
   rtnetlink_rcv_msg+0x346/0x8e0
   netlink_unicast+0x439/0x630
   netlink_sendmsg+0x719/0xbf0
   sock_sendmsg+0xe2/0x110
   ____sys_sendmsg+0x5ba/0x890
   ___sys_sendmsg+0xe9/0x160
   __sys_sendmsg+0xd3/0x170
   do_syscall_64+0x33/0x40
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  [...]
  ODEBUG: assert_init not available (active state 0) object type: timer_list hint: 0x0
  WARNING: CPU: 0 PID: 975 at lib/debugobjects.c:508 debug_print_object+0x162/0x210
  [...]
  Call Trace:
   debug_object_assert_init+0x268/0x380
   try_to_del_timer_sync+0x6a/0x100
   del_timer_sync+0x9e/0xd0
   fq_pie_destroy+0x3f/0x80 [sch_fq_pie]
   qdisc_create+0x916/0x1160
   tc_modify_qdisc+0x3c4/0x1630
   rtnetlink_rcv_msg+0x346/0x8e0
   netlink_rcv_skb+0x120/0x380
   netlink_unicast+0x439/0x630
   netlink_sendmsg+0x719/0xbf0
   sock_sendmsg+0xe2/0x110
   ____sys_sendmsg+0x5ba/0x890
   ___sys_sendmsg+0xe9/0x160
   __sys_sendmsg+0xd3/0x170
   do_syscall_64+0x33/0x40
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

fix it moving timer_setup() before any failure, like it was done on 'red'
with former commit 608b4adab178 ("net_sched: initialize timer earlier in
red_init()").

Fixes: ec97ecf1ebe4 ("net: sched: add Flow Queue PIE packet scheduler")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Reviewed-by: Cong Wang <cong.wang@bytedance.com>
Link: https://lore.kernel.org/r/2e78e01c504c633ebdff18d041833cf2e079a3a4.1607020450.git.dcaratti@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net/sched/sch_fq_pie.c