* [PATCH] net/sched: Set the flushing flags to false to prevent an infinite loop
@ 2023-06-06 14:45 renmingshuai
2023-06-06 16:59 ` Pedro Tammela
0 siblings, 1 reply; 8+ messages in thread
From: renmingshuai @ 2023-06-06 14:45 UTC (permalink / raw)
To: netdev, linux-kernel, jhs, xiyou.wangcong, jiri, davem, edumazet,
kuba, pabeni
Cc: liaichun, caowangbao, yanan, liubo335
When a new chain is added by using tc, one soft lockup alarm will be
generated after delete the prio 0 filter of the chain. To reproduce
the problem, perform the following steps:
(1) tc qdisc add dev eth0 root handle 1: htb default 1
(2) tc chain add dev eth0
(3) tc filter del dev eth0 chain 0 parent 1: prio 0
(4) tc filter add dev eth0 chain 0 parent 1:
The refcnt of the chain added by step 2 is equal to 1. After step 3,
the flushing flag of the chain is set to true in the tcf_chain_flush()
called by tc_del_tfilter() because the prio is 0. In this case, if
we add a new filter to this chain, it will never succeed and try again
and again because the refresh flash is always true and refcnt is 1.
A soft lock alarm is generated 20 seconds later.
The stack is show as below:
Kernel panic - not syncing: softlockup: hung tasks
CPU: 2 PID: 3321861 Comm: tc Kdump: loaded Tainted: G
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
Call Trace:
<IRQ>
dump_stack+0x57/0x6e
panic+0x196/0x3ec
watchdog_timer_fn.cold+0x16/0x5c
__run_hrtimer+0x5e/0x190
__hrtimer_run_queues+0x8a/0xe0
hrtimer_interrupt+0x110/0x2c0
? irqtime_account_irq+0x49/0xf0
__sysvec_apic_timer_interrupt+0x5f/0xe0
asm_call_irq_on_stack+0x12/0x20
</IRQ>
sysvec_apic_timer_interrupt+0x72/0x80
asm_sysvec_apic_timer_interrupt+0x12/0x20
RIP: 0010:mutex_lock+0x24/0x70
RSP: 0018:ffffa836004ab9a8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff95bb02d76700 RCX: 0000000000000000
RDX: ffff95bb27462100 RSI: 0000000000000000 RDI: ffff95ba5b527000
RBP: ffff95ba5b527000 R08: 0000000000000001 R09: ffffa836004abbb8
R10: 000000000000000f R11: 0000000000000000 R12: 0000000000000000
R13: ffff95ba5b527000 R14: ffffa836004abbb8 R15: 0000000000000001
__tcf_chain_put+0x27/0x200
tc_new_tfilter+0x5e8/0x810
? tc_setup_cb_add+0x210/0x210
rtnetlink_rcv_msg+0x2e3/0x380
? rtnl_calcit.isra.0+0x120/0x120
netlink_rcv_skb+0x50/0x100
netlink_unicast+0x12d/0x1d0
netlink_sendmsg+0x286/0x490
sock_sendmsg+0x62/0x70
____sys_sendmsg+0x24c/0x2c0
? import_iovec+0x17/0x20
? sendmsg_copy_msghdr+0x80/0xa0
___sys_sendmsg+0x75/0xc0
? do_fault_around+0x118/0x160
? do_read_fault+0x68/0xf0
? __handle_mm_fault+0x3f9/0x6f0
__sys_sendmsg+0x59/0xa0
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x61/0xc6
RIP: 0033:0x7f96705b8247
RSP: 002b:00007ffe552e9dc8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f96705b8247
RDX: 0000000000000000 RSI: 00007ffe552e9e40 RDI: 0000000000000003
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000558113f678b0
R10: 00007f967069ab00 R11: 0000000000000246 R12: 00000000647ea089
R13: 00007ffe552e9f30 R14: 0000000000000001 R15: 0000558113175f00
To avoid this case, set chain->flushing to be false if the chain->refcnt
is 1 after flushing the chain when prio is 0.
Fixes: 726d061286ce ("net: sched: prevent insertion of new classifiers during chain flush")
Signed-off-by: Ren Mingshuai <renmingshuai@huawei.com>
---
net/sched/cls_api.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 2621550bfddc..68be55d75831 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -2442,6 +2442,13 @@ static int tc_del_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
tfilter_notify_chain(net, skb, block, q, parent, n,
chain, RTM_DELTFILTER, extack);
tcf_chain_flush(chain, rtnl_held);
+ /* Set the flushing flags to false to prevent an infinite loop
+ * when a new filter is added.
+ */
+ mutex_lock(&chain->filter_chain_lock);
+ if (chain->refcnt == 1)
+ chain->flushing = false;
+ mutex_unlock(&chain->filter_chain_lock);
err = 0;
goto errout;
}
--
2.27.0
^ permalink raw reply related [flat|nested] 8+ messages in thread* Re: [PATCH] net/sched: Set the flushing flags to false to prevent an infinite loop 2023-06-06 14:45 [PATCH] net/sched: Set the flushing flags to false to prevent an infinite loop renmingshuai @ 2023-06-06 16:59 ` Pedro Tammela 2023-06-07 4:19 ` renmingshuai 0 siblings, 1 reply; 8+ messages in thread From: Pedro Tammela @ 2023-06-06 16:59 UTC (permalink / raw) To: renmingshuai, netdev, linux-kernel, jhs, xiyou.wangcong, jiri, davem, edumazet, kuba, pabeni Cc: liaichun, caowangbao, yanan, liubo335 On 06/06/2023 11:45, renmingshuai wrote: > When a new chain is added by using tc, one soft lockup alarm will be > generated after delete the prio 0 filter of the chain. To reproduce > the problem, perform the following steps: > (1) tc qdisc add dev eth0 root handle 1: htb default 1 > (2) tc chain add dev eth0 > (3) tc filter del dev eth0 chain 0 parent 1: prio 0 > (4) tc filter add dev eth0 chain 0 parent 1: This seems like it could be added to tdc or 3 and 4 must be run in parallel? > > > The refcnt of the chain added by step 2 is equal to 1. After step 3, > the flushing flag of the chain is set to true in the tcf_chain_flush() > called by tc_del_tfilter() because the prio is 0. In this case, if > we add a new filter to this chain, it will never succeed and try again > and again because the refresh flash is always true and refcnt is 1. > A soft lock alarm is generated 20 seconds later. > The stack is show as below: > > Kernel panic - not syncing: softlockup: hung tasks > CPU: 2 PID: 3321861 Comm: tc Kdump: loaded Tainted: G > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) > Call Trace: > <IRQ> > dump_stack+0x57/0x6e > panic+0x196/0x3ec > watchdog_timer_fn.cold+0x16/0x5c > __run_hrtimer+0x5e/0x190 > __hrtimer_run_queues+0x8a/0xe0 > hrtimer_interrupt+0x110/0x2c0 > ? irqtime_account_irq+0x49/0xf0 > __sysvec_apic_timer_interrupt+0x5f/0xe0 > asm_call_irq_on_stack+0x12/0x20 > </IRQ> > sysvec_apic_timer_interrupt+0x72/0x80 > asm_sysvec_apic_timer_interrupt+0x12/0x20 > RIP: 0010:mutex_lock+0x24/0x70 > RSP: 0018:ffffa836004ab9a8 EFLAGS: 00000246 > RAX: 0000000000000000 RBX: ffff95bb02d76700 RCX: 0000000000000000 > RDX: ffff95bb27462100 RSI: 0000000000000000 RDI: ffff95ba5b527000 > RBP: ffff95ba5b527000 R08: 0000000000000001 R09: ffffa836004abbb8 > R10: 000000000000000f R11: 0000000000000000 R12: 0000000000000000 > R13: ffff95ba5b527000 R14: ffffa836004abbb8 R15: 0000000000000001 > __tcf_chain_put+0x27/0x200 > tc_new_tfilter+0x5e8/0x810 > ? tc_setup_cb_add+0x210/0x210 > rtnetlink_rcv_msg+0x2e3/0x380 > ? rtnl_calcit.isra.0+0x120/0x120 > netlink_rcv_skb+0x50/0x100 > netlink_unicast+0x12d/0x1d0 > netlink_sendmsg+0x286/0x490 > sock_sendmsg+0x62/0x70 > ____sys_sendmsg+0x24c/0x2c0 > ? import_iovec+0x17/0x20 > ? sendmsg_copy_msghdr+0x80/0xa0 > ___sys_sendmsg+0x75/0xc0 > ? do_fault_around+0x118/0x160 > ? do_read_fault+0x68/0xf0 > ? __handle_mm_fault+0x3f9/0x6f0 > __sys_sendmsg+0x59/0xa0 > do_syscall_64+0x33/0x40 > entry_SYSCALL_64_after_hwframe+0x61/0xc6 > RIP: 0033:0x7f96705b8247 > RSP: 002b:00007ffe552e9dc8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f96705b8247 > RDX: 0000000000000000 RSI: 00007ffe552e9e40 RDI: 0000000000000003 > RBP: 0000000000000001 R08: 0000000000000001 R09: 0000558113f678b0 > R10: 00007f967069ab00 R11: 0000000000000246 R12: 00000000647ea089 > R13: 00007ffe552e9f30 R14: 0000000000000001 R15: 0000558113175f00 > > To avoid this case, set chain->flushing to be false if the chain->refcnt > is 1 after flushing the chain when prio is 0. > > Fixes: 726d061286ce ("net: sched: prevent insertion of new classifiers during chain flush") > Signed-off-by: Ren Mingshuai <renmingshuai@huawei.com> > --- > net/sched/cls_api.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c > index 2621550bfddc..68be55d75831 100644 > --- a/net/sched/cls_api.c > +++ b/net/sched/cls_api.c > @@ -2442,6 +2442,13 @@ static int tc_del_tfilter(struct sk_buff *skb, struct nlmsghdr *n, > tfilter_notify_chain(net, skb, block, q, parent, n, > chain, RTM_DELTFILTER, extack); > tcf_chain_flush(chain, rtnl_held); > + /* Set the flushing flags to false to prevent an infinite loop > + * when a new filter is added. > + */ > + mutex_lock(&chain->filter_chain_lock); > + if (chain->refcnt == 1) > + chain->flushing = false; > + mutex_unlock(&chain->filter_chain_lock); > err = 0; > goto errout; > } ^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH] net/sched: Set the flushing flags to false to prevent an infinite loop 2023-06-06 16:59 ` Pedro Tammela @ 2023-06-07 4:19 ` renmingshuai 2023-06-07 15:02 ` Pedro Tammela 0 siblings, 1 reply; 8+ messages in thread From: renmingshuai @ 2023-06-07 4:19 UTC (permalink / raw) To: pctammela Cc: caowangbao, davem, edumazet, jhs, jiri, kuba, liaichun, linux-kernel, liubo335, netdev, pabeni, renmingshuai, xiyou.wangcong, yanan >On 06/06/2023 11:45, renmingshuai wrote: >> When a new chain is added by using tc, one soft lockup alarm will be >> generated after delete the prio 0 filter of the chain. To reproduce >> the problem, perform the following steps: >> (1) tc qdisc add dev eth0 root handle 1: htb default 1 >> (2) tc chain add dev eth0 >> (3) tc filter del dev eth0 chain 0 parent 1: prio 0 >> (4) tc filter add dev eth0 chain 0 parent 1: > >This seems like it could be added to tdc or 3 and 4 must be run in parallel? 3 and 4 do not need to be run inparallel. When a new chain is added by the way as step 1 and the step 3 is completed, this problem always occurs whenever step 4 is run. >> >> >> The refcnt of the chain added by step 2 is equal to 1. After step 3, >> the flushing flag of the chain is set to true in the tcf_chain_flush() >> called by tc_del_tfilter() because the prio is 0. In this case, if >> we add a new filter to this chain, it will never succeed and try again >> and again because the refresh flash is always true and refcnt is 1. >> A soft lock alarm is generated 20 seconds later. >> The stack is show as below: >> >> Kernel panic - not syncing: softlockup: hung tasks >> CPU: 2 PID: 3321861 Comm: tc Kdump: loaded Tainted: G >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) >> Call Trace: >> <IRQ> >> dump_stack+0x57/0x6e >> panic+0x196/0x3ec >> watchdog_timer_fn.cold+0x16/0x5c >> __run_hrtimer+0x5e/0x190 >> __hrtimer_run_queues+0x8a/0xe0 >> hrtimer_interrupt+0x110/0x2c0 >> ? irqtime_account_irq+0x49/0xf0 >> __sysvec_apic_timer_interrupt+0x5f/0xe0 >> asm_call_irq_on_stack+0x12/0x20 >> </IRQ> >> sysvec_apic_timer_interrupt+0x72/0x80 >> asm_sysvec_apic_timer_interrupt+0x12/0x20 >> RIP: 0010:mutex_lock+0x24/0x70 >> RSP: 0018:ffffa836004ab9a8 EFLAGS: 00000246 >> RAX: 0000000000000000 RBX: ffff95bb02d76700 RCX: 0000000000000000 >> RDX: ffff95bb27462100 RSI: 0000000000000000 RDI: ffff95ba5b527000 >> RBP: ffff95ba5b527000 R08: 0000000000000001 R09: ffffa836004abbb8 >> R10: 000000000000000f R11: 0000000000000000 R12: 0000000000000000 >> R13: ffff95ba5b527000 R14: ffffa836004abbb8 R15: 0000000000000001 >> __tcf_chain_put+0x27/0x200 >> tc_new_tfilter+0x5e8/0x810 >> ? tc_setup_cb_add+0x210/0x210 >> rtnetlink_rcv_msg+0x2e3/0x380 >> ? rtnl_calcit.isra.0+0x120/0x120 >> netlink_rcv_skb+0x50/0x100 >> netlink_unicast+0x12d/0x1d0 >> netlink_sendmsg+0x286/0x490 >> sock_sendmsg+0x62/0x70 >> ____sys_sendmsg+0x24c/0x2c0 >> ? import_iovec+0x17/0x20 >> ? sendmsg_copy_msghdr+0x80/0xa0 >> ___sys_sendmsg+0x75/0xc0 >> ? do_fault_around+0x118/0x160 >> ? do_read_fault+0x68/0xf0 >> ? __handle_mm_fault+0x3f9/0x6f0 >> __sys_sendmsg+0x59/0xa0 >> do_syscall_64+0x33/0x40 >> entry_SYSCALL_64_after_hwframe+0x61/0xc6 >> RIP: 0033:0x7f96705b8247 >> RSP: 002b:00007ffe552e9dc8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e >> RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f96705b8247 >> RDX: 0000000000000000 RSI: 00007ffe552e9e40 RDI: 0000000000000003 >> RBP: 0000000000000001 R08: 0000000000000001 R09: 0000558113f678b0 >> R10: 00007f967069ab00 R11: 0000000000000246 R12: 00000000647ea089 >> R13: 00007ffe552e9f30 R14: 0000000000000001 R15: 0000558113175f00 >> >> To avoid this case, set chain->flushing to be false if the chain->refcnt >> is 1 after flushing the chain when prio is 0. >> >> Fixes: 726d061286ce ("net: sched: prevent insertion of new classifiers during chain flush") >> Signed-off-by: Ren Mingshuai <renmingshuai@huawei.com> >> --- >> net/sched/cls_api.c | 7 +++++++ >> 1 file changed, 7 insertions(+) >> >> diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c >> index 2621550bfddc..68be55d75831 100644 >> --- a/net/sched/cls_api.c >> +++ b/net/sched/cls_api.c >> @@ -2442,6 +2442,13 @@ static int tc_del_tfilter(struct sk_buff *skb, struct nlmsghdr *n, >> tfilter_notify_chain(net, skb, block, q, parent, n, >> chain, RTM_DELTFILTER, extack); >> tcf_chain_flush(chain, rtnl_held); >> + /* Set the flushing flags to false to prevent an infinite loop >> + * when a new filter is added. >> + */ >> + mutex_lock(&chain->filter_chain_lock); >> + if (chain->refcnt == 1) >> + chain->flushing = false; >> + mutex_unlock(&chain->filter_chain_lock); >> err = 0; >> goto errout; >> } ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] net/sched: Set the flushing flags to false to prevent an infinite loop 2023-06-07 4:19 ` renmingshuai @ 2023-06-07 15:02 ` Pedro Tammela 2023-06-08 12:32 ` [PATCH v2] net/sched: Set the flushing flags to false to prevent an infinite loop and add one test to tdc renmingshuai 0 siblings, 1 reply; 8+ messages in thread From: Pedro Tammela @ 2023-06-07 15:02 UTC (permalink / raw) To: renmingshuai Cc: caowangbao, davem, edumazet, jhs, jiri, kuba, liaichun, linux-kernel, liubo335, netdev, pabeni, xiyou.wangcong, yanan On 07/06/2023 01:19, renmingshuai wrote: >> On 06/06/2023 11:45, renmingshuai wrote: >>> When a new chain is added by using tc, one soft lockup alarm will be >>> generated after delete the prio 0 filter of the chain. To reproduce >>> the problem, perform the following steps: >>> (1) tc qdisc add dev eth0 root handle 1: htb default 1 >>> (2) tc chain add dev eth0 >>> (3) tc filter del dev eth0 chain 0 parent 1: prio 0 >>> (4) tc filter add dev eth0 chain 0 parent 1: >> >> This seems like it could be added to tdc or 3 and 4 must be run in parallel? > 3 and 4 do not need to be run inparallel. When a new chain is added by the > way as step 1 and the step 3 is completed, this problem always occurs > whenever step 4 is run. Got it, The test still hangs with the provided patch. + tc qdisc add dev lo root handle 1: htb default 1 + tc chain add dev lo + tc filter del dev lo chain 0 parent 1: prio 0 [ 68.790030][ T6704] [+] [ 68.790060][ T6704] chain refcnt 2 [ 68.790951][ T6704] [-] + tc filter add dev lo chain 0 parent 1: <hangs> Also please add this test to tdc, it should be straightforward. >>> >>> >>> The refcnt of the chain added by step 2 is equal to 1. After step 3, >>> the flushing flag of the chain is set to true in the tcf_chain_flush() >>> called by tc_del_tfilter() because the prio is 0. In this case, if >>> we add a new filter to this chain, it will never succeed and try again >>> and again because the refresh flash is always true and refcnt is 1. >>> A soft lock alarm is generated 20 seconds later. >>> The stack is show as below: >>> >>> Kernel panic - not syncing: softlockup: hung tasks >>> CPU: 2 PID: 3321861 Comm: tc Kdump: loaded Tainted: G >>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) >>> Call Trace: >>> <IRQ> >>> dump_stack+0x57/0x6e >>> panic+0x196/0x3ec >>> watchdog_timer_fn.cold+0x16/0x5c >>> __run_hrtimer+0x5e/0x190 >>> __hrtimer_run_queues+0x8a/0xe0 >>> hrtimer_interrupt+0x110/0x2c0 >>> ? irqtime_account_irq+0x49/0xf0 >>> __sysvec_apic_timer_interrupt+0x5f/0xe0 >>> asm_call_irq_on_stack+0x12/0x20 >>> </IRQ> >>> sysvec_apic_timer_interrupt+0x72/0x80 >>> asm_sysvec_apic_timer_interrupt+0x12/0x20 >>> RIP: 0010:mutex_lock+0x24/0x70 >>> RSP: 0018:ffffa836004ab9a8 EFLAGS: 00000246 >>> RAX: 0000000000000000 RBX: ffff95bb02d76700 RCX: 0000000000000000 >>> RDX: ffff95bb27462100 RSI: 0000000000000000 RDI: ffff95ba5b527000 >>> RBP: ffff95ba5b527000 R08: 0000000000000001 R09: ffffa836004abbb8 >>> R10: 000000000000000f R11: 0000000000000000 R12: 0000000000000000 >>> R13: ffff95ba5b527000 R14: ffffa836004abbb8 R15: 0000000000000001 >>> __tcf_chain_put+0x27/0x200 >>> tc_new_tfilter+0x5e8/0x810 >>> ? tc_setup_cb_add+0x210/0x210 >>> rtnetlink_rcv_msg+0x2e3/0x380 >>> ? rtnl_calcit.isra.0+0x120/0x120 >>> netlink_rcv_skb+0x50/0x100 >>> netlink_unicast+0x12d/0x1d0 >>> netlink_sendmsg+0x286/0x490 >>> sock_sendmsg+0x62/0x70 >>> ____sys_sendmsg+0x24c/0x2c0 >>> ? import_iovec+0x17/0x20 >>> ? sendmsg_copy_msghdr+0x80/0xa0 >>> ___sys_sendmsg+0x75/0xc0 >>> ? do_fault_around+0x118/0x160 >>> ? do_read_fault+0x68/0xf0 >>> ? __handle_mm_fault+0x3f9/0x6f0 >>> __sys_sendmsg+0x59/0xa0 >>> do_syscall_64+0x33/0x40 >>> entry_SYSCALL_64_after_hwframe+0x61/0xc6 >>> RIP: 0033:0x7f96705b8247 >>> RSP: 002b:00007ffe552e9dc8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e >>> RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f96705b8247 >>> RDX: 0000000000000000 RSI: 00007ffe552e9e40 RDI: 0000000000000003 >>> RBP: 0000000000000001 R08: 0000000000000001 R09: 0000558113f678b0 >>> R10: 00007f967069ab00 R11: 0000000000000246 R12: 00000000647ea089 >>> R13: 00007ffe552e9f30 R14: 0000000000000001 R15: 0000558113175f00 >>> >>> To avoid this case, set chain->flushing to be false if the chain->refcnt >>> is 1 after flushing the chain when prio is 0. >>> >>> Fixes: 726d061286ce ("net: sched: prevent insertion of new classifiers during chain flush") >>> Signed-off-by: Ren Mingshuai <renmingshuai@huawei.com> >>> --- >>> net/sched/cls_api.c | 7 +++++++ >>> 1 file changed, 7 insertions(+) >>> >>> diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c >>> index 2621550bfddc..68be55d75831 100644 >>> --- a/net/sched/cls_api.c >>> +++ b/net/sched/cls_api.c >>> @@ -2442,6 +2442,13 @@ static int tc_del_tfilter(struct sk_buff *skb, struct nlmsghdr *n, >>> tfilter_notify_chain(net, skb, block, q, parent, n, >>> chain, RTM_DELTFILTER, extack); >>> tcf_chain_flush(chain, rtnl_held); >>> + /* Set the flushing flags to false to prevent an infinite loop >>> + * when a new filter is added. >>> + */ >>> + mutex_lock(&chain->filter_chain_lock); >>> + if (chain->refcnt == 1) >>> + chain->flushing = false; >>> + mutex_unlock(&chain->filter_chain_lock); >>> err = 0; >>> goto errout; >>> } ^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH v2] net/sched: Set the flushing flags to false to prevent an infinite loop and add one test to tdc 2023-06-07 15:02 ` Pedro Tammela @ 2023-06-08 12:32 ` renmingshuai 2023-06-08 16:08 ` Pedro Tammela 0 siblings, 1 reply; 8+ messages in thread From: renmingshuai @ 2023-06-08 12:32 UTC (permalink / raw) To: pctammela Cc: caowangbao, davem, edumazet, jhs, jiri, kuba, liaichun, linux-kernel, liubo335, netdev, pabeni, renmingshuai, xiyou.wangcong, yanan >On 07/06/2023 01:19, renmingshuai wrote: >>> On 06/06/2023 11:45, renmingshuai wrote: >>>> When a new chain is added by using tc, one soft lockup alarm will >>>> be >>>> generated after delete the prio 0 filter of the chain. To >>>> reproduce >>>> the problem, perform the following steps: >>>> (1) tc qdisc add dev eth0 root handle 1: htb default 1 >>>> (2) tc chain add dev eth0 >>>> (3) tc filter del dev eth0 chain 0 parent 1: prio 0 >>>> (4) tc filter add dev eth0 chain 0 parent 1: >>> >>> This seems like it could be added to tdc or 3 and 4 must be run in >>> parallel? >> 3 and 4 do not need to be run inparallel. When a new chain is added >> by the >> way as step 1 and the step 3 is completed, this problem always >> occurs >> whenever step 4 is run. > >Got it, >The test still hangs with the provided patch. > >+ tc qdisc add dev lo root handle 1: htb default 1 >+ tc chain add dev lo >+ tc filter del dev lo chain 0 parent 1: prio 0 >[ 68.790030][ T6704] [+] >[ 68.790060][ T6704] chain refcnt 2 >[ 68.790951][ T6704] [-] >+ tc filter add dev lo chain 0 parent 1: ><hangs> > >Also please add this test to tdc, it should be straightforward. > Sorry for not testing before. I forgot that the chain->refcnt was increased by 1 when tcf_chain_get() is called in tc_del_tfilter(). The value of chain->refcnt is 2 after chain flush. The test result is as follows: [root@localhost ~]# tc qdisc add dev eth2 root handle 1: htb default 1 [root@localhost ~]# tc chain add dev eth2 [root@localhost ~]# tc filter del dev eth2 chain 0 parent 1: prio 0 [root@localhost ~]# tc filter add dev eth2 chain 0 parent 1: Error: Filter kind and protocol must be specified. We have an error talking to the kernel And I have add this test to tdc: [root@localhost tc-testing]# ./tdc.py -f tc-tests/filters/tests.json ok 7 c2b4 - Adding a new fiter after deleting a filter in a chain does not cause an infinite loop Fixes: 726d061286ce ("net: sched: prevent insertion of new classifiers during chain flush") Signed-off-by: renmingshuai <renmingshuai@huawei.com> --- net/sched/cls_api.c | 7 +++++ .../tc-testing/tc-tests/filters/tests.json | 26 ++++++++++++++++--- 2 files changed, 30 insertions(+), 3 deletions(-) diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index 2621550bfddc..3ea054e03fbf 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -2442,6 +2442,13 @@ static int tc_del_tfilter(struct sk_buff *skb, struct nlmsghdr *n, tfilter_notify_chain(net, skb, block, q, parent, n, chain, RTM_DELTFILTER, extack); tcf_chain_flush(chain, rtnl_held); + /* Set the flushing flags to false to prevent an infinite loop + * when a new filter is added. + */ + mutex_lock(&chain->filter_chain_lock); + if (chain->refcnt == 2) + chain->flushing = false; + mutex_unlock(&chain->filter_chain_lock); err = 0; goto errout; } diff --git a/tools/testing/selftests/tc-testing/tc-tests/filters/tests.json b/tools/testing/selftests/tc-testing/tc-tests/filters/tests.json index 361235ad574b..f165ca091109 100644 --- a/tools/testing/selftests/tc-testing/tc-tests/filters/tests.json +++ b/tools/testing/selftests/tc-testing/tc-tests/filters/tests.json @@ -125,5 +125,25 @@ "teardown": [ "$TC qdisc del dev $DEV2 ingress" ] + }, + { + "id": "c2b4", + "name": "Adding a new fiter after deleting a filter in a chain does not cause an infinite loop", + "category": [ + "filter", + "prio" + ], + "setup": [ + "$TC qdisc add dev $DEV1 root handle 1: htb default 1", + "$TC chain add dev $DEV1" + ], + "cmdUnderTest": "$TC filter del dev $DEV1 chain 0 parent 1: prio 0", + "expExitCode": "0", + "verifyCmd": "$TC filter add dev $DEV1 chain 0 parent 1:", + "matchPattern": "Error: Filter kind and protocol must be specified.", + "matchCount": "1", + "teardown": [ + "$TC qdisc del dev $DEV1 root handle 1: htb default 1" + ] } ] -- 2.27.0 >>>> >>>> >>>> The refcnt of the chain added by step 2 is equal to 1. After step >>>> 3, >>>> the flushing flag of the chain is set to true in the >>>> tcf_chain_flush() >>>> called by tc_del_tfilter() because the prio is 0. In this case, >>>> if >>>> we add a new filter to this chain, it will never succeed and try >>>> again >>>> and again because the refresh flash is always true and refcnt is >>>> 1. >>>> A soft lock alarm is generated 20 seconds later. >>>> The stack is show as below: >>>> >>>> Kernel panic - not syncing: softlockup: hung tasks >>>> CPU: 2 PID: 3321861 Comm: tc Kdump: loaded Tainted: G >>>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) >>>> Call Trace: >>>> <IRQ> >>>> dump_stack+0x57/0x6e >>>> panic+0x196/0x3ec >>>> watchdog_timer_fn.cold+0x16/0x5c >>>> __run_hrtimer+0x5e/0x190 >>>> __hrtimer_run_queues+0x8a/0xe0 >>>> hrtimer_interrupt+0x110/0x2c0 >>>> ? irqtime_account_irq+0x49/0xf0 >>>> __sysvec_apic_timer_interrupt+0x5f/0xe0 >>>> asm_call_irq_on_stack+0x12/0x20 >>>> </IRQ> >>>> sysvec_apic_timer_interrupt+0x72/0x80 >>>> asm_sysvec_apic_timer_interrupt+0x12/0x20 >>>> RIP: 0010:mutex_lock+0x24/0x70 >>>> RSP: 0018:ffffa836004ab9a8 EFLAGS: 00000246 >>>> RAX: 0000000000000000 RBX: ffff95bb02d76700 RCX: 0000000000000000 >>>> RDX: ffff95bb27462100 RSI: 0000000000000000 RDI: ffff95ba5b527000 >>>> RBP: ffff95ba5b527000 R08: 0000000000000001 R09: ffffa836004abbb8 >>>> R10: 000000000000000f R11: 0000000000000000 R12: 0000000000000000 >>>> R13: ffff95ba5b527000 R14: ffffa836004abbb8 R15: 0000000000000001 >>>> __tcf_chain_put+0x27/0x200 >>>> tc_new_tfilter+0x5e8/0x810 >>>> ? tc_setup_cb_add+0x210/0x210 >>>> rtnetlink_rcv_msg+0x2e3/0x380 >>>> ? rtnl_calcit.isra.0+0x120/0x120 >>>> netlink_rcv_skb+0x50/0x100 >>>> netlink_unicast+0x12d/0x1d0 >>>> netlink_sendmsg+0x286/0x490 >>>> sock_sendmsg+0x62/0x70 >>>> ____sys_sendmsg+0x24c/0x2c0 >>>> ? import_iovec+0x17/0x20 >>>> ? sendmsg_copy_msghdr+0x80/0xa0 >>>> ___sys_sendmsg+0x75/0xc0 >>>> ? do_fault_around+0x118/0x160 >>>> ? do_read_fault+0x68/0xf0 >>>> ? __handle_mm_fault+0x3f9/0x6f0 >>>> __sys_sendmsg+0x59/0xa0 >>>> do_syscall_64+0x33/0x40 >>>> entry_SYSCALL_64_after_hwframe+0x61/0xc6 >>>> RIP: 0033:0x7f96705b8247 >>>> RSP: 002b:00007ffe552e9dc8 EFLAGS: 00000246 ORIG_RAX: >>>> 000000000000002e >>>> RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f96705b8247 >>>> RDX: 0000000000000000 RSI: 00007ffe552e9e40 RDI: 0000000000000003 >>>> RBP: 0000000000000001 R08: 0000000000000001 R09: 0000558113f678b0 >>>> R10: 00007f967069ab00 R11: 0000000000000246 R12: 00000000647ea089 >>>> R13: 00007ffe552e9f30 R14: 0000000000000001 R15: 0000558113175f00 >>>> >>>> To avoid this case, set chain->flushing to be false if the >>>> chain->refcnt >>>> is 1 after flushing the chain when prio is 0. >>>> >>>> Fixes: 726d061286ce ("net: sched: prevent insertion of new >>>> classifiers during chain flush") >>>> Signed-off-by: Ren Mingshuai <renmingshuai@huawei.com> >>>> --- >>>> net/sched/cls_api.c | 7 +++++++ >>>> 1 file changed, 7 insertions(+) >>>> >>>> diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c >>>> index 2621550bfddc..68be55d75831 100644 >>>> --- a/net/sched/cls_api.c >>>> +++ b/net/sched/cls_api.c >>>> @@ -2442,6 +2442,13 @@ static int tc_del_tfilter(struct sk_buff >>>> *skb, struct nlmsghdr *n, >>>> tfilter_notify_chain(net, skb, block, q, parent, >>>> n, >>>> chain, RTM_DELTFILTER, >>>> extack); >>>> tcf_chain_flush(chain, rtnl_held); >>>> + /* Set the flushing flags to false to prevent an >>>> infinite loop >>>> + * when a new filter is added. >>>> + */ >>>> + mutex_lock(&chain->filter_chain_lock); >>>> + if (chain->refcnt == 1) >>>> + chain->flushing = false; >>>> + mutex_unlock(&chain->filter_chain_lock); >>>> err = 0; >>>> goto errout; >>>> } ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH v2] net/sched: Set the flushing flags to false to prevent an infinite loop and add one test to tdc 2023-06-08 12:32 ` [PATCH v2] net/sched: Set the flushing flags to false to prevent an infinite loop and add one test to tdc renmingshuai @ 2023-06-08 16:08 ` Pedro Tammela 2023-06-09 3:31 ` [PATCH v3] " renmingshuai 0 siblings, 1 reply; 8+ messages in thread From: Pedro Tammela @ 2023-06-08 16:08 UTC (permalink / raw) To: renmingshuai Cc: caowangbao, davem, edumazet, jhs, jiri, kuba, liaichun, linux-kernel, liubo335, netdev, pabeni, xiyou.wangcong, yanan On 08/06/2023 09:32, renmingshuai wrote: >> On 07/06/2023 01:19, renmingshuai wrote: >>>> On 06/06/2023 11:45, renmingshuai wrote: >>>>> When a new chain is added by using tc, one soft lockup alarm will >>>>> be >>>>> generated after delete the prio 0 filter of the chain. To >>>>> reproduce >>>>> the problem, perform the following steps: >>>>> (1) tc qdisc add dev eth0 root handle 1: htb default 1 >>>>> (2) tc chain add dev eth0 >>>>> (3) tc filter del dev eth0 chain 0 parent 1: prio 0 >>>>> (4) tc filter add dev eth0 chain 0 parent 1: >>>> >>>> This seems like it could be added to tdc or 3 and 4 must be run in >>>> parallel? >>> 3 and 4 do not need to be run inparallel. When a new chain is added >>> by the >>> way as step 1 and the step 3 is completed, this problem always >>> occurs >>> whenever step 4 is run. >> >> Got it, >> The test still hangs with the provided patch. >> >> + tc qdisc add dev lo root handle 1: htb default 1 >> + tc chain add dev lo >> + tc filter del dev lo chain 0 parent 1: prio 0 >> [ 68.790030][ T6704] [+] >> [ 68.790060][ T6704] chain refcnt 2 >> [ 68.790951][ T6704] [-] >> + tc filter add dev lo chain 0 parent 1: >> <hangs> >> >> Also please add this test to tdc, it should be straightforward. >> > Sorry for not testing before. I forgot that the chain->refcnt was > increased by 1 when tcf_chain_get() is called in tc_del_tfilter(). > The value of chain->refcnt is 2 after chain flush. The test > result is as follows: > [root@localhost ~]# tc qdisc add dev eth2 root handle 1: htb default 1 > [root@localhost ~]# tc chain add dev eth2 > [root@localhost ~]# tc filter del dev eth2 chain 0 parent 1: prio 0 > [root@localhost ~]# tc filter add dev eth2 chain 0 parent 1: > Error: Filter kind and protocol must be specified. > We have an error talking to the kernel > > And I have add this test to tdc: > [root@localhost tc-testing]# ./tdc.py -f tc-tests/filters/tests.json > ok 7 c2b4 - Adding a new fiter after deleting a filter in a chain does > not cause an infinite loop > > Fixes: 726d061286ce ("net: sched: prevent insertion of new classifiers during chain flush") > Signed-off-by: renmingshuai <renmingshuai@huawei.com> Please respin with the following applied: diff --git a/tools/testing/selftests/tc-testing/tc-tests/filters/tests.json b/tools/testing/selftests/tc-testing/tc-tests/filters/tests.json index c759c3db9a37..361235ad574b 100644 --- a/tools/testing/selftests/tc-testing/tc-tests/filters/tests.json +++ b/tools/testing/selftests/tc-testing/tc-tests/filters/tests.json @@ -125,25 +125,5 @@ "teardown": [ "$TC qdisc del dev $DEV2 ingress" ] - }, - { - "id": "c2b4", - "name": "Adding a new fiter after deleting a filter in a chain does not cause an infinite loop", - "category": [ - "filter", - "prio" - ], - "setup": [ - "$TC qdisc add dev $DEV1 root handle 1: htb default 1", - "$TC chain add dev $DEV1" - ], - "cmdUnderTest": "$TC filter del dev $DEV1 chain 0 parent 1: prio 0", - "expExitCode": "0", - "verifyCmd": "$TC filter add dev $DEV1 chain 0 parent 1:", - "matchPattern": "Error: Filter kind and protocol must be specified.", - "matchCount": "1", - "teardown": [ - "$TC qdisc del dev $DEV1 root handle 1: htb default 1" - ] } ] diff --git a/tools/testing/selftests/tc-testing/tc-tests/infra/filters.json b/tools/testing/selftests/tc-testing/tc-tests/infra/filters. json new file mode 100644 index 000000000000..55d6f209c388 --- /dev/null +++ b/tools/testing/selftests/tc-testing/tc-tests/infra/filters.json @@ -0,0 +1,24 @@ +[ + { + "id": "c2b4", + "name": "Adding a new filter after flushing empty chain doesnt cause an infinite loop", + "category": [ + "filter", + "chain" + ], + "setup": [ + "$IP link add dev $DUMMY type dummy || /bin/true", + "$TC qdisc add dev $DUMMY root handle 1: htb default 1", + "$TC chain add dev $DUMMY", + "$TC filter del dev $DUMMY chain 0 parent 1: prio 0" + ], + "cmdUnderTest": "$TC filter add dev $DUMMY chain 0 parent 1:", + "expExitCode": "2", + "verifyCmd": "$TC chain ls dev $DUMMY", + "matchPattern": "chain parent 1: chain 0", + "matchCount": "1", + "teardown": [ + "$TC qdisc del dev $DUMMY root handle 1: htb default 1" + ] + } +] ^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH v3] net/sched: Set the flushing flags to false to prevent an infinite loop and add one test to tdc 2023-06-08 16:08 ` Pedro Tammela @ 2023-06-09 3:31 ` renmingshuai 2023-06-09 8:24 ` Simon Horman 0 siblings, 1 reply; 8+ messages in thread From: renmingshuai @ 2023-06-09 3:31 UTC (permalink / raw) To: pctammela Cc: caowangbao, davem, edumazet, jhs, jiri, kuba, liaichun, linux-kernel, liubo335, netdev, pabeni, renmingshuai, xiyou.wangcong, yanan >On 08/06/2023 09:32, renmingshuai wrote: >>> On 07/06/2023 01:19, renmingshuai wrote: >>>>> On 06/06/2023 11:45, renmingshuai wrote: >>>>>> When a new chain is added by using tc, one soft lockup alarm will >>>>>> be >>>>>> generated after delete the prio 0 filter of the chain. To >>>>>> reproduce >>>>>> the problem, perform the following steps: >>>>>> (1) tc qdisc add dev eth0 root handle 1: htb default 1 >>>>>> (2) tc chain add dev eth0 >>>>>> (3) tc filter del dev eth0 chain 0 parent 1: prio 0 >>>>>> (4) tc filter add dev eth0 chain 0 parent 1: >>>>> >>>>> This seems like it could be added to tdc or 3 and 4 must be run in >>>>> parallel? >>>> 3 and 4 do not need to be run inparallel. When a new chain is added >>>> by the >>>> way as step 1 and the step 3 is completed, this problem always >>>> occurs >>>> whenever step 4 is run. >>> >>> Got it, >>> The test still hangs with the provided patch. >>> >>> + tc qdisc add dev lo root handle 1: htb default 1 >>> + tc chain add dev lo >>> + tc filter del dev lo chain 0 parent 1: prio 0 >>> [ 68.790030][ T6704] [+] >>> [ 68.790060][ T6704] chain refcnt 2 >>> [ 68.790951][ T6704] [-] >>> + tc filter add dev lo chain 0 parent 1: >>> <hangs> >>> >>> Also please add this test to tdc, it should be straightforward. >>> >> Sorry for not testing before. I forgot that the chain->refcnt was >> increased by 1 when tcf_chain_get() is called in tc_del_tfilter(). >> The value of chain->refcnt is 2 after chain flush. The test >> result is as follows: >> [root@localhost ~]# tc qdisc add dev eth2 root handle 1: htb default 1 >> [root@localhost ~]# tc chain add dev eth2 >> [root@localhost ~]# tc filter del dev eth2 chain 0 parent 1: prio 0 >> [root@localhost ~]# tc filter add dev eth2 chain 0 parent 1: >> Error: Filter kind and protocol must be specified. >> We have an error talking to the kernel >> >> And I have add this test to tdc: >> [root@localhost tc-testing]# ./tdc.py -f tc-tests/filters/tests.json >> ok 7 c2b4 - Adding a new fiter after deleting a filter in a chain does >> not cause an infinite loop >> >> Fixes: 726d061286ce ("net: sched: prevent insertion of new classifiers during chain flush") >> Signed-off-by: renmingshuai <renmingshuai@huawei.com> > >Please respin with the following applied: > >diff --git >a/tools/testing/selftests/tc-testing/tc-tests/filters/tests.json >b/tools/testing/selftests/tc-testing/tc-tests/filters/tests.json >index c759c3db9a37..361235ad574b 100644 >--- a/tools/testing/selftests/tc-testing/tc-tests/filters/tests.json >+++ b/tools/testing/selftests/tc-testing/tc-tests/filters/tests.json >@@ -125,25 +125,5 @@ > "teardown": [ > "$TC qdisc del dev $DEV2 ingress" > ] >- }, >- { >- "id": "c2b4", >- "name": "Adding a new fiter after deleting a filter in a chain >does not cause an infinite loop", >- "category": [ >- "filter", >- "prio" >- ], >- "setup": [ >- "$TC qdisc add dev $DEV1 root handle 1: htb default 1", >- "$TC chain add dev $DEV1" >- ], >- "cmdUnderTest": "$TC filter del dev $DEV1 chain 0 parent 1: >prio 0", >- "expExitCode": "0", >- "verifyCmd": "$TC filter add dev $DEV1 chain 0 parent 1:", >- "matchPattern": "Error: Filter kind and protocol must be >specified.", >- "matchCount": "1", >- "teardown": [ >- "$TC qdisc del dev $DEV1 root handle 1: htb default 1" >- ] > } > ] >diff --git >a/tools/testing/selftests/tc-testing/tc-tests/infra/filters.json >b/tools/testing/selftests/tc-testing/tc-tests/infra/filters. >json >new file mode 100644 >index 000000000000..55d6f209c388 >--- /dev/null >+++ b/tools/testing/selftests/tc-testing/tc-tests/infra/filters.json >@@ -0,0 +1,24 @@ >+[ >+ { >+ "id": "c2b4", >+ "name": "Adding a new filter after flushing empty chain doesnt >cause an infinite loop", >+ "category": [ >+ "filter", >+ "chain" >+ ], >+ "setup": [ >+ "$IP link add dev $DUMMY type dummy || /bin/true", >+ "$TC qdisc add dev $DUMMY root handle 1: htb default 1", >+ "$TC chain add dev $DUMMY", >+ "$TC filter del dev $DUMMY chain 0 parent 1: prio 0" >+ ], >+ "cmdUnderTest": "$TC filter add dev $DUMMY chain 0 parent 1:", >+ "expExitCode": "2", >+ "verifyCmd": "$TC chain ls dev $DUMMY", >+ "matchPattern": "chain parent 1: chain 0", >+ "matchCount": "1", >+ "teardown": [ >+ "$TC qdisc del dev $DUMMY root handle 1: htb default 1" >+ ] >+ } >+] Ok. The new test is passed. [root@localhost tc-testing]# ./tdc.py -f tc-tests/infra/filter.json Test c2b4: Adding a new filter after flushing empty chain doesn't cause an infinite loop All test results: 1..1 ok 1 c2b4 - Adding a new filter after flushing empty chain doesn't cause an infinite loop Fixes: 726d061286ce ("net: sched: prevent insertion of new classifiers during chain flush") Signed-off-by: renmingshuai <renmingshuai@huawei.com> --- net/sched/cls_api.c | 7 ++++++ .../tc-testing/tc-tests/infra/filter.json | 25 +++++++++++++++++++ 2 files changed, 32 insertions(+) create mode 100644 tools/testing/selftests/tc-testing/tc-tests/infra/filter.json diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index 2621550bfddc..3ea054e03fbf 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -2442,6 +2442,13 @@ static int tc_del_tfilter(struct sk_buff *skb, struct nlmsghdr *n, tfilter_notify_chain(net, skb, block, q, parent, n, chain, RTM_DELTFILTER, extack); tcf_chain_flush(chain, rtnl_held); + /* Set the flushing flags to false to prevent an infinite loop + * when a new filter is added. + */ + mutex_lock(&chain->filter_chain_lock); + if (chain->refcnt == 2) + chain->flushing = false; + mutex_unlock(&chain->filter_chain_lock); err = 0; goto errout; } diff --git a/tools/testing/selftests/tc-testing/tc-tests/infra/filter.json b/tools/testing/selftests/tc-testing/tc-tests/infra/filter.json new file mode 100644 index 000000000000..db3b42aaa4fa --- /dev/null +++ b/tools/testing/selftests/tc-testing/tc-tests/infra/filter.json @@ -0,0 +1,25 @@ +[ + { + "id": "c2b4", + "name": "Adding a new filter after flushing empty chain doesn't cause an infinite loop", + "category": [ + "filter", + "chain" + ], + "setup": [ + "$IP link add dev $DUMMY type dummy || /bin/true", + "$TC qdisc add dev $DUMMY root handle 1: htb default 1", + "$TC chain add dev $DUMMY", + "$TC filter del dev $DUMMY chain 0 parent 1: prio 0" + ], + "cmdUnderTest": "$TC filter add dev $DUMMY chain 0 parent 1:", + "expExitCode": "2", + "verifyCmd": "$TC chain ls dev $DUMMY", + "matchPattern": "chain parent 1: chain 0", + "matchCount": "1", + "teardown": [ + "$TC qdisc del dev $DUMMY root handle 1: htb default 1", + "$IP link del dev $DUMMY type dummy" + ] + } +] -- 2.27.0 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH v3] net/sched: Set the flushing flags to false to prevent an infinite loop and add one test to tdc 2023-06-09 3:31 ` [PATCH v3] " renmingshuai @ 2023-06-09 8:24 ` Simon Horman 0 siblings, 0 replies; 8+ messages in thread From: Simon Horman @ 2023-06-09 8:24 UTC (permalink / raw) To: renmingshuai Cc: pctammela, caowangbao, davem, edumazet, jhs, jiri, kuba, liaichun, linux-kernel, liubo335, netdev, pabeni, xiyou.wangcong, yanan On Fri, Jun 09, 2023 at 11:31:15AM +0800, renmingshuai wrote: > >On 08/06/2023 09:32, renmingshuai wrote: > >>> On 07/06/2023 01:19, renmingshuai wrote: > >>>>> On 06/06/2023 11:45, renmingshuai wrote: > >>>>>> When a new chain is added by using tc, one soft lockup alarm will > >>>>>> be > >>>>>> generated after delete the prio 0 filter of the chain. To > >>>>>> reproduce > >>>>>> the problem, perform the following steps: > >>>>>> (1) tc qdisc add dev eth0 root handle 1: htb default 1 > >>>>>> (2) tc chain add dev eth0 > >>>>>> (3) tc filter del dev eth0 chain 0 parent 1: prio 0 > >>>>>> (4) tc filter add dev eth0 chain 0 parent 1: > >>>>> > >>>>> This seems like it could be added to tdc or 3 and 4 must be run in > >>>>> parallel? > >>>> 3 and 4 do not need to be run inparallel. When a new chain is added > >>>> by the > >>>> way as step 1 and the step 3 is completed, this problem always > >>>> occurs > >>>> whenever step 4 is run. > >>> > >>> Got it, > >>> The test still hangs with the provided patch. > >>> > >>> + tc qdisc add dev lo root handle 1: htb default 1 > >>> + tc chain add dev lo > >>> + tc filter del dev lo chain 0 parent 1: prio 0 > >>> [ 68.790030][ T6704] [+] > >>> [ 68.790060][ T6704] chain refcnt 2 > >>> [ 68.790951][ T6704] [-] > >>> + tc filter add dev lo chain 0 parent 1: > >>> <hangs> > >>> > >>> Also please add this test to tdc, it should be straightforward. > >>> > >> Sorry for not testing before. I forgot that the chain->refcnt was > >> increased by 1 when tcf_chain_get() is called in tc_del_tfilter(). > >> The value of chain->refcnt is 2 after chain flush. The test > >> result is as follows: > >> [root@localhost ~]# tc qdisc add dev eth2 root handle 1: htb default 1 > >> [root@localhost ~]# tc chain add dev eth2 > >> [root@localhost ~]# tc filter del dev eth2 chain 0 parent 1: prio 0 > >> [root@localhost ~]# tc filter add dev eth2 chain 0 parent 1: > >> Error: Filter kind and protocol must be specified. > >> We have an error talking to the kernel > >> > >> And I have add this test to tdc: > >> [root@localhost tc-testing]# ./tdc.py -f tc-tests/filters/tests.json > >> ok 7 c2b4 - Adding a new fiter after deleting a filter in a chain does > >> not cause an infinite loop > >> > >> Fixes: 726d061286ce ("net: sched: prevent insertion of new classifiers during chain flush") > >> Signed-off-by: renmingshuai <renmingshuai@huawei.com> > > > >Please respin with the following applied: > > > >diff --git > >a/tools/testing/selftests/tc-testing/tc-tests/filters/tests.json > >b/tools/testing/selftests/tc-testing/tc-tests/filters/tests.json > >index c759c3db9a37..361235ad574b 100644 > >--- a/tools/testing/selftests/tc-testing/tc-tests/filters/tests.json > >+++ b/tools/testing/selftests/tc-testing/tc-tests/filters/tests.json > >@@ -125,25 +125,5 @@ > > "teardown": [ > > "$TC qdisc del dev $DEV2 ingress" > > ] > >- }, > >- { > >- "id": "c2b4", > >- "name": "Adding a new fiter after deleting a filter in a chain > >does not cause an infinite loop", > >- "category": [ > >- "filter", > >- "prio" > >- ], > >- "setup": [ > >- "$TC qdisc add dev $DEV1 root handle 1: htb default 1", > >- "$TC chain add dev $DEV1" > >- ], > >- "cmdUnderTest": "$TC filter del dev $DEV1 chain 0 parent 1: > >prio 0", > >- "expExitCode": "0", > >- "verifyCmd": "$TC filter add dev $DEV1 chain 0 parent 1:", > >- "matchPattern": "Error: Filter kind and protocol must be > >specified.", > >- "matchCount": "1", > >- "teardown": [ > >- "$TC qdisc del dev $DEV1 root handle 1: htb default 1" > >- ] > > } > > ] > >diff --git > >a/tools/testing/selftests/tc-testing/tc-tests/infra/filters.json > >b/tools/testing/selftests/tc-testing/tc-tests/infra/filters. > >json > >new file mode 100644 > >index 000000000000..55d6f209c388 > >--- /dev/null > >+++ b/tools/testing/selftests/tc-testing/tc-tests/infra/filters.json > >@@ -0,0 +1,24 @@ > >+[ > >+ { > >+ "id": "c2b4", > >+ "name": "Adding a new filter after flushing empty chain doesnt > >cause an infinite loop", > >+ "category": [ > >+ "filter", > >+ "chain" > >+ ], > >+ "setup": [ > >+ "$IP link add dev $DUMMY type dummy || /bin/true", > >+ "$TC qdisc add dev $DUMMY root handle 1: htb default 1", > >+ "$TC chain add dev $DUMMY", > >+ "$TC filter del dev $DUMMY chain 0 parent 1: prio 0" > >+ ], > >+ "cmdUnderTest": "$TC filter add dev $DUMMY chain 0 parent 1:", > >+ "expExitCode": "2", > >+ "verifyCmd": "$TC chain ls dev $DUMMY", > >+ "matchPattern": "chain parent 1: chain 0", > >+ "matchCount": "1", > >+ "teardown": [ > >+ "$TC qdisc del dev $DUMMY root handle 1: htb default 1" > >+ ] > >+ } > >+] > > Ok. The new test is passed. > [root@localhost tc-testing]# ./tdc.py -f tc-tests/infra/filter.json > Test c2b4: Adding a new filter after flushing empty chain doesn't cause an infinite loop > All test results: > 1..1 > ok 1 c2b4 - Adding a new filter after flushing empty chain doesn't cause an infinite loop > > Fixes: 726d061286ce ("net: sched: prevent insertion of new classifiers during chain flush") > Signed-off-by: renmingshuai <renmingshuai@huawei.com> Hi renmingshuai, the above text, in it's entirety, does not meet the needs of a patch submission for the Linux kernel. In particular: * All the context from previous discussion (the bits prefixed by '>') should be removed. * The patch description should consist of just that, a description of the patch. Any relevant test results are also welcome here. * Information about changes from previous versions should be provided in the form of a changelog, typically below the scissors (---). A recent example is here: - https://lore.kernel.org/all/20230607162353.3631199-1-mtottenh@akamai.com/ [PATCH v3] net/sched: act_pedit: Parse L3 Header for L4 offset Also, please consider using spaces and capital letters in your name in the from and signed-off parts of your submission. e.g.: Mingshuai Ren <...> or Ren Mingshuai <...> ... -- pw-bot: cr ^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2023-06-09 8:25 UTC | newest] Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2023-06-06 14:45 [PATCH] net/sched: Set the flushing flags to false to prevent an infinite loop renmingshuai 2023-06-06 16:59 ` Pedro Tammela 2023-06-07 4:19 ` renmingshuai 2023-06-07 15:02 ` Pedro Tammela 2023-06-08 12:32 ` [PATCH v2] net/sched: Set the flushing flags to false to prevent an infinite loop and add one test to tdc renmingshuai 2023-06-08 16:08 ` Pedro Tammela 2023-06-09 3:31 ` [PATCH v3] " renmingshuai 2023-06-09 8:24 ` Simon Horman
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