[PATCH 4.9 06/25] net_sched: Fix missing res info when create new tc_index filter

Greg Kroah-Hartman
2018-08-21T06:33:43Z

From: Hangbin Liu <liuhangbin@gmail.com>

[ Upstream commit 008369dcc5f7bfba526c98054f8525322acf0ea3 ]

Li Shuang reported the following warn:

[ 733.484610] WARNING: CPU: 6 PID: 21123 at net/sched/sch_cbq.c:1418 cbq_destroy_class+0x5d/0x70 [sch_cbq]
[ 733.495190] Modules linked in: sch_cbq cls_tcindex sch_dsmark rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache xt_CHECKSUM iptable_mangle ipt_MASQUERADE iptable_nat l
[ 733.574155] syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm igb ixgbe ahci libahci i2c_algo_bit libata i40e i2c_core dca mdio megaraid_sas dm_mirror dm_region_hash dm_log dm_mod
[ 733.592500] CPU: 6 PID: 21123 Comm: tc Not tainted 4.18.0-rc8.latest+ #131
[ 733.600169] Hardware name: Dell Inc. PowerEdge R730/0WCJNT, BIOS 2.1.5 04/11/2016
[ 733.608518] RIP: 0010:cbq_destroy_class+0x5d/0x70 [sch_cbq]
[ 733.614734] Code: e7 d9 d2 48 8b 7b 48 e8 61 05 da d2 48 8d bb f8 00 00 00 e8 75 ae d5 d2 48 39 eb 74 0a 48 89 df 5b 5d e9 16 6c 94 d2 5b 5d c3 <0f> 0b eb b6 0f 1f 44 00 00 66 2e 0f 1f 84
[ 733.635798] RSP: 0018:ffffbfbb066bb9d8 EFLAGS: 00010202
[ 733.641627] RAX: 0000000000000001 RBX: ffff9cdd17392800 RCX: 000000008010000f
[ 733.649588] RDX: ffff9cdd1df547e0 RSI: ffff9cdd17392800 RDI: ffff9cdd0f84c800
[ 733.657547] RBP: ffff9cdd0f84c800 R08: 0000000000000001 R09: 0000000000000000
[ 733.665508] R10: ffff9cdd0f84d000 R11: 0000000000000001 R12: 0000000000000001
[ 733.673469] R13: 0000000000000000 R14: 0000000000000001 R15: ffff9cdd17392200
[ 733.681430] FS: 00007f911890a740(0000) GS:ffff9cdd1f8c0000(0000) knlGS:0000000000000000
[ 733.690456] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 733.696864] CR2: 0000000000b5544c CR3: 0000000859374002 CR4: 00000000001606e0
[ 733.704826] Call Trace:
[ 733.707554] cbq_destroy+0xa1/0xd0 [sch_cbq]
[ 733.712318] qdisc_destroy+0x62/0x130
[ 733.716401] dsmark_destroy+0x2a/0x70 [sch_dsmark]
[ 733.721745] qdisc_destroy+0x62/0x130
[ 733.725829] qdisc_graft+0x3ba/0x470
[ 733.729817] tc_get_qdisc+0x2a6/0x2c0
[ 733.733901] ? cred_has_capability+0x7d/0x130
[ 733.738761] rtnetlink_rcv_msg+0x263/0x2d0
[ 733.743330] ? rtnl_calcit.isra.30+0x110/0x110
[ 733.748287] netlink_rcv_skb+0x4d/0x130
[ 733.752576] netlink_unicast+0x1a3/0x250
[ 733.756949] netlink_sendmsg+0x2ae/0x3a0
[ 733.761324] sock_sendmsg+0x36/0x40
[ 733.765213] ___sys_sendmsg+0x26f/0x2d0
[ 733.769493] ? handle_pte_fault+0x586/0xdf0
[ 733.774158] ? __handle_mm_fault+0x389/0x500
[ 733.778919] ? __sys_sendmsg+0x5e/0xa0
[ 733.783099] __sys_sendmsg+0x5e/0xa0
[ 733.787087] do_syscall_64+0x5b/0x180
[ 733.791171] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 733.796805] RIP: 0033:0x7f9117f23f10
[ 733.800791] Code: c3 48 8b 05 82 6f 2c 00 f7 db 64 89 18 48 83 cb ff eb dd 0f 1f 80 00 00 00 00 83 3d 8d d0 2c 00 00 75 10 b8 2e 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8
[ 733.821873] RSP: 002b:00007ffe96818398 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[ 733.830319] RAX: ffffffffffffffda RBX: 000000005b71244c RCX: 00007f9117f23f10
[ 733.838280] RDX: 0000000000000000 RSI: 00007ffe968183e0 RDI: 0000000000000003
[ 733.846241] RBP: 00007ffe968183e0 R08: 000000000000ffff R09: 0000000000000003
[ 733.854202] R10: 00007ffe96817e20 R11: 0000000000000246 R12: 0000000000000000
[ 733.862161] R13: 0000000000662ee0 R14: 0000000000000000 R15: 0000000000000000
[ 733.870121] ---[ end trace 28edd4aad712ddca ]---

This is because we didn't update f->result.res when create new filter. Then in
tcindex_delete() -> tcf_unbind_filter(), we will failed to find out the res
and unbind filter, which will trigger the WARN_ON() in cbq_destroy_class().

Fix it by updating f->result.res when create new filter.

Fixes: 6e0565697a106 ("net_sched: fix another crash in cls_tcindex")
Reported-by: Li Shuang <shuali@redhat.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/sched/cls_tcindex.c | 1 +
1 file changed, 1 insertion(+)

--- a/net/sched/cls_tcindex.c
+++ b/net/sched/cls_tcindex.c
@@ -435,6 +435,7 @@ tcindex_set_parms(struct net *net, struc
struct tcindex_filter *nfp;
struct tcindex_filter __rcu **fp;

+ f->result.res = r->res;
tcf_exts_change(tp, &f->result.exts, &r->exts);

fp = cp->h + (handle % cp->hash);