This is a note to let you know that I've just added the patch titled net/sched: fq_pie: initialize timer earlier in fq_pie_init() to the 5.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-sched-fq_pie-initialize-timer-earlier-in-fq_pie_init.patch and it can be found in the queue-5.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Sat Dec 19 11:38:43 AM CET 2020 From: Davide Caratti <dcaratti@xxxxxxxxxx> Date: Thu, 3 Dec 2020 19:40:47 +0100 Subject: net/sched: fq_pie: initialize timer earlier in fq_pie_init() From: Davide Caratti <dcaratti@xxxxxxxxxx> [ Upstream commit 4eef8b1f36f2ff06966b8f7c2143ef0c447877de ] 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@xxxxxxxxxx> Reviewed-by: Cong Wang <cong.wang@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/2e78e01c504c633ebdff18d041833cf2e079a3a4.1607020450.git.dcaratti@xxxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/sched/sch_fq_pie.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/sched/sch_fq_pie.c +++ b/net/sched/sch_fq_pie.c @@ -401,6 +401,7 @@ static int fq_pie_init(struct Qdisc *sch INIT_LIST_HEAD(&q->new_flows); INIT_LIST_HEAD(&q->old_flows); + timer_setup(&q->adapt_timer, fq_pie_timer, 0); if (opt) { err = fq_pie_change(sch, opt, extack); @@ -426,7 +427,6 @@ static int fq_pie_init(struct Qdisc *sch pie_vars_init(&flow->vars); } - timer_setup(&q->adapt_timer, fq_pie_timer, 0); mod_timer(&q->adapt_timer, jiffies + HZ / 2); return 0; Patches currently in stable-queue which might be from dcaratti@xxxxxxxxxx are queue-5.9/net-sched-fq_pie-initialize-timer-earlier-in-fq_pie_init.patch