From: Davide Caratti dcaratti@redhat.com
[ Upstream commit bb2f930d6dd708469a587dc9ed1efe1ef969c0bf ]
this command hangs forever:
# tc qdisc add dev eth0 root fq_pie flows 65536
watchdog: BUG: soft lockup - CPU#1 stuck for 23s! [tc:1028] [...] CPU: 1 PID: 1028 Comm: tc Not tainted 5.7.0-rc6+ #167 RIP: 0010:fq_pie_init+0x60e/0x8b7 [sch_fq_pie] Code: 4c 89 65 50 48 89 f8 48 c1 e8 03 42 80 3c 30 00 0f 85 2a 02 00 00 48 8d 7d 10 4c 89 65 58 48 89 f8 48 c1 e8 03 42 80 3c 30 00 <0f> 85 a7 01 00 00 48 8d 7d 18 48 c7 45 10 46 c3 23 00 48 89 f8 48 RSP: 0018:ffff888138d67468 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 1ffff9200018d2b2 RBX: ffff888139c1c400 RCX: ffffffffffffffff RDX: 000000000000c5e8 RSI: ffffc900000e5000 RDI: ffffc90000c69590 RBP: ffffc90000c69580 R08: fffffbfff79a9699 R09: fffffbfff79a9699 R10: 0000000000000700 R11: fffffbfff79a9698 R12: ffffc90000c695d0 R13: 0000000000000000 R14: dffffc0000000000 R15: 000000002347c5e8 FS: 00007f01e1850e40(0000) GS:ffff88814c880000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000067c340 CR3: 000000013864c000 CR4: 0000000000340ee0 Call Trace: qdisc_create+0x3fd/0xeb0 tc_modify_qdisc+0x3be/0x14a0 rtnetlink_rcv_msg+0x5f3/0x920 netlink_rcv_skb+0x121/0x350 netlink_unicast+0x439/0x630 netlink_sendmsg+0x714/0xbf0 sock_sendmsg+0xe2/0x110 ____sys_sendmsg+0x5b4/0x890 ___sys_sendmsg+0xe9/0x160 __sys_sendmsg+0xd3/0x170 do_syscall_64+0x9a/0x370 entry_SYSCALL_64_after_hwframe+0x44/0xa9
we can't accept 65536 as a valid number for 'nflows', because the loop on 'idx' in fq_pie_init() will never end. The extack message is correct, but it doesn't say that 0 is not a valid number for 'flows': while at it, fix this also. Add a tdc selftest to check correct validation of 'flows'.
CC: Ivan Vecera ivecera@redhat.com Fixes: ec97ecf1ebe4 ("net: sched: add Flow Queue PIE packet scheduler") Signed-off-by: Davide Caratti dcaratti@redhat.com Reviewed-by: Ivan Vecera ivecera@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sched/sch_fq_pie.c | 4 - tools/testing/selftests/tc-testing/tc-tests/qdiscs/fq_pie.json | 21 ++++++++++ 2 files changed, 23 insertions(+), 2 deletions(-) create mode 100644 tools/testing/selftests/tc-testing/tc-tests/qdiscs/fq_pie.json
--- a/net/sched/sch_fq_pie.c +++ b/net/sched/sch_fq_pie.c @@ -298,9 +298,9 @@ static int fq_pie_change(struct Qdisc *s goto flow_error; } q->flows_cnt = nla_get_u32(tb[TCA_FQ_PIE_FLOWS]); - if (!q->flows_cnt || q->flows_cnt > 65536) { + if (!q->flows_cnt || q->flows_cnt >= 65536) { NL_SET_ERR_MSG_MOD(extack, - "Number of flows must be < 65536"); + "Number of flows must range in [1..65535]"); goto flow_error; } } --- /dev/null +++ b/tools/testing/selftests/tc-testing/tc-tests/qdiscs/fq_pie.json @@ -0,0 +1,21 @@ +[ + { + "id": "83be", + "name": "Create FQ-PIE with invalid number of flows", + "category": [ + "qdisc", + "fq_pie" + ], + "setup": [ + "$IP link add dev $DUMMY type dummy || /bin/true" + ], + "cmdUnderTest": "$TC qdisc add dev $DUMMY root fq_pie flows 65536", + "expExitCode": "2", + "verifyCmd": "$TC qdisc show dev $DUMMY", + "matchPattern": "qdisc", + "matchCount": "0", + "teardown": [ + "$IP link del dev $DUMMY" + ] + } +]