Message-Id: <1535958623-7050-1-git-send-email-vladbu@mellanox.com>
Date:   Mon,  3 Sep 2018 10:10:23 +0300
From:   Vlad Buslov <vladbu@...lanox.com>
To:     netdev@...r.kernel.org
Cc:     jhs@...atatu.com, xiyou.wangcong@...il.com, jiri@...nulli.us,
        davem@...emloft.net, Vlad Buslov <vladbu@...lanox.com>
Subject: [PATCH net-next] net: sched: action_ife: take reference to meta module

Recent refactoring of add_metainfo() caused use_all_metadata() to add
metainfo to ife action metalist without taking reference to module. This
causes warning in module_put called from ife action cleanup function.

Implement add_metainfo_and_get_ops() function that returns with reference
to module taken if metainfo was added successfully, and call it from
use_all_metadata(), instead of calling __add_metainfo() directly.

Example warning:

[  646.344393] WARNING: CPU: 1 PID: 2278 at kernel/module.c:1139 module_put+0x1cb/0x230
[  646.352437] Modules linked in: act_meta_skbtcindex act_meta_mark act_meta_skbprio act_ife ife veth nfsv3 nfs fscache xt_CHECKSUM iptable_mangle ipt_MASQUERADE iptable_nat nf_nat_ipv4 nf_nat xt_conntrack nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c tun ebtable_filter ebtables ip6table_filter ip6_tables bridge stp llc mlx5_ib ib_uverbs ib_core intel_rapl sb_edac x86_pkg_temp_thermal mlx5_core coretemp kvm_intel kvm nfsd igb irqbypass crct10dif_pclmul devlink crc32_pclmul mei_me joydev ses crc32c_intel enclosure auth_rpcgss i2c_algo_bit ioatdma ptp mei pps_core ghash_clmulni_intel iTCO_wdt iTCO_vendor_support pcspkr dca ipmi_ssif lpc_ich target_core_mod i2c_i801 ipmi_si ipmi_devintf pcc_cpufreq wmi ipmi_msghandler nfs_acl lockd acpi_pad acpi_power_meter grace sunrpc mpt3sas raid_class scsi_transport_sas
[  646.425631] CPU: 1 PID: 2278 Comm: tc Not tainted 4.19.0-rc1+ #799
[  646.432187] Hardware name: Supermicro SYS-2028TP-DECR/X10DRT-P, BIOS 2.0b 03/30/2017
[  646.440595] RIP: 0010:module_put+0x1cb/0x230
[  646.445238] Code: f3 66 94 02 e8 26 ff fa ff 85 c0 74 11 0f b6 1d 51 30 94 02 80 fb 01 77 60 83 e3 01 74 13 65 ff 0d 3a 83 db 73 e9 2b ff ff ff <0f> 0b e9 00 ff ff ff e8 59 01 fb ff 85 c0 75 e4 48 c7 c2 20 62 6b
[  646.464997] RSP: 0018:ffff880354d37068 EFLAGS: 00010286
[  646.470599] RAX: 0000000000000000 RBX: ffffffffc0a52518 RCX: ffffffff8c2668db
[  646.478118] RDX: 0000000000000003 RSI: dffffc0000000000 RDI: ffffffffc0a52518
[  646.485641] RBP: ffffffffc0a52180 R08: fffffbfff814a4a4 R09: fffffbfff814a4a3
[  646.493164] R10: ffffffffc0a5251b R11: fffffbfff814a4a4 R12: 1ffff1006a9a6e0d
[  646.500687] R13: 00000000ffffffff R14: ffff880362bab890 R15: dead000000000100
[  646.508213] FS:  00007f4164c99800(0000) GS:ffff88036fe40000(0000) knlGS:0000000000000000
[  646.516961] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  646.523080] CR2: 00007f41638b8420 CR3: 0000000351df0004 CR4: 00000000001606e0
[  646.530595] Call Trace:
[  646.533408]  ? find_symbol_in_section+0x260/0x260
[  646.538509]  tcf_ife_cleanup+0x11b/0x200 [act_ife]
[  646.543695]  tcf_action_cleanup+0x29/0xa0
[  646.548078]  __tcf_action_put+0x5a/0xb0
[  646.552289]  ? nla_put+0x65/0xe0
[  646.555889]  __tcf_idr_release+0x48/0x60
[  646.560187]  tcf_generic_walker+0x448/0x6b0
[  646.564764]  ? tcf_action_dump_1+0x450/0x450
[  646.569411]  ? __lock_is_held+0x84/0x110
[  646.573720]  ? tcf_ife_walker+0x10c/0x20f [act_ife]
[  646.578982]  tca_action_gd+0x972/0xc40
[  646.583129]  ? tca_get_fill.constprop.17+0x250/0x250
[  646.588471]  ? mark_lock+0xcf/0x980
[  646.592324]  ? check_chain_key+0x140/0x1f0
[  646.596832]  ? debug_show_all_locks+0x240/0x240
[  646.601839]  ? memset+0x1f/0x40
[  646.605350]  ? nla_parse+0xca/0x1a0
[  646.609217]  tc_ctl_action+0x215/0x230
[  646.613339]  ? tcf_action_add+0x220/0x220
[  646.617748]  rtnetlink_rcv_msg+0x56a/0x6d0
[  646.622227]  ? rtnl_fdb_del+0x3f0/0x3f0
[  646.626466]  netlink_rcv_skb+0x18d/0x200
[  646.630752]  ? rtnl_fdb_del+0x3f0/0x3f0
[  646.634959]  ? netlink_ack+0x500/0x500
[  646.639106]  netlink_unicast+0x2d0/0x370
[  646.643409]  ? netlink_attachskb+0x340/0x340
[  646.648050]  ? _copy_from_iter_full+0xe9/0x3e0
[  646.652870]  ? import_iovec+0x11e/0x1c0
[  646.657083]  netlink_sendmsg+0x3b9/0x6a0
[  646.661388]  ? netlink_unicast+0x370/0x370
[  646.665877]  ? netlink_unicast+0x370/0x370
[  646.670351]  sock_sendmsg+0x6b/0x80
[  646.674212]  ___sys_sendmsg+0x4a1/0x520
[  646.678443]  ? copy_msghdr_from_user+0x210/0x210
[  646.683463]  ? lock_downgrade+0x320/0x320
[  646.687849]  ? debug_show_all_locks+0x240/0x240
[  646.692760]  ? do_raw_spin_unlock+0xa2/0x130
[  646.697418]  ? _raw_spin_unlock+0x24/0x30
[  646.701798]  ? __handle_mm_fault+0x1819/0x1c10
[  646.706619]  ? __pmd_alloc+0x320/0x320
[  646.710738]  ? debug_show_all_locks+0x240/0x240
[  646.715649]  ? restore_nameidata+0x7b/0xa0
[  646.720117]  ? check_chain_key+0x140/0x1f0
[  646.724590]  ? check_chain_key+0x140/0x1f0
[  646.729070]  ? __fget_light+0xbc/0xd0
[  646.733121]  ? __sys_sendmsg+0xd7/0x150
[  646.737329]  __sys_sendmsg+0xd7/0x150
[  646.741359]  ? __ia32_sys_shutdown+0x30/0x30
[  646.746003]  ? up_read+0x53/0x90
[  646.749601]  ? __do_page_fault+0x484/0x780
[  646.754105]  ? do_syscall_64+0x1e/0x2c0
[  646.758320]  do_syscall_64+0x72/0x2c0
[  646.762353]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[  646.767776] RIP: 0033:0x7f4163872150
[  646.771713] Code: 8b 15 3c 7d 2b 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb cd 66 0f 1f 44 00 00 83 3d b9 d5 2b 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 be cd 00 00 48 89 04 24
[  646.791474] RSP: 002b:00007ffdef7d6b58 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[  646.799721] RAX: ffffffffffffffda RBX: 0000000000000024 RCX: 00007f4163872150
[  646.807240] RDX: 0000000000000000 RSI: 00007ffdef7d6bd0 RDI: 0000000000000003
[  646.814760] RBP: 000000005b8b9482 R08: 0000000000000001 R09: 0000000000000000
[  646.822286] R10: 00000000000005e7 R11: 0000000000000246 R12: 00007ffdef7dad20
[  646.829807] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000679bc0
[  646.837360] irq event stamp: 6083
[  646.841043] hardirqs last  enabled at (6081): [<ffffffff8c220a7d>] __call_rcu+0x17d/0x500
[  646.849882] hardirqs last disabled at (6083): [<ffffffff8c004f06>] trace_hardirqs_off_thunk+0x1a/0x1c
[  646.859775] softirqs last  enabled at (5968): [<ffffffff8d4004a1>] __do_softirq+0x4a1/0x6ee
[  646.868784] softirqs last disabled at (6082): [<ffffffffc0a78759>] tcf_ife_cleanup+0x39/0x200 [act_ife]
[  646.878845] ---[ end trace b1b8c12ffe51e657 ]---

Fixes: 5ffe57da29b3 ("act_ife: fix a potential deadlock")
Signed-off-by: Vlad Buslov <vladbu@...lanox.com>
---
 net/sched/act_ife.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/net/sched/act_ife.c b/net/sched/act_ife.c
index 19454146f60d..d8ea10259934 100644
--- a/net/sched/act_ife.c
+++ b/net/sched/act_ife.c
@@ -326,6 +326,21 @@ static int __add_metainfo(const struct tcf_meta_ops *ops,
 	return ret;
 }
 
+static int add_metainfo_and_get_ops(const struct tcf_meta_ops *ops,
+				    struct tcf_ife_info *ife, u32 metaid,
+				    void *metaval, int len, bool atomic,
+				    bool exists)
+{
+	int ret;
+
+	if (!try_module_get(ops->owner))
+		return -ENOENT;
+	ret = __add_metainfo(ops, ife, metaid, metaval, len, false, exists);
+	if (ret)
+		module_put(ops->owner);
+	return ret;
+}
+
 static int add_metainfo(struct tcf_ife_info *ife, u32 metaid, void *metaval,
 			int len, bool exists)
 {
@@ -349,7 +364,8 @@ static int use_all_metadata(struct tcf_ife_info *ife, bool exists)
 
 	read_lock(&ife_mod_lock);
 	list_for_each_entry(o, &ifeoplist, list) {
-		rc = __add_metainfo(o, ife, o->metaid, NULL, 0, true, exists);
+		rc = add_metainfo_and_get_ops(o, ife, o->metaid, NULL, 0, true,
+					      exists);
 		if (rc == 0)
 			installed += 1;
 	}
-- 
2.7.5

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