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From:   hui yang <yanghui.def@gmail.com>
To:     paul@paul-moore.com
Cc:     sds@tycho.nsa.gov, eparis@parisplace.org, selinux@vger.kernel.org,
        linux-kernel@vger.kernel.org, YangHui <yanghui.def@gmail.com>
Subject: [PATCH] netnode.c : fix sel_netnode_hash be destroyed
Date:   Fri, 20 Dec 2019 18:07:21 +0800
Message-Id: <1576836441-4140-1-git-send-email-yanghui.def@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: YangHui <yanghui.def@gmail.com>

we often find below error :
[   30.729718] Unable to handle kernel paging request at virtual address fffffffffffffffc
[   30.747478] Kernel BUG at sel_netnode_find+0x6c/0xf0 [verbose debug info unavailable]
[   30.818858] PC is at sel_netnode_find+0x6c/0xf0
[   30.824671] LR is at sel_netnode_sid+0x3c/0x248
[   30.829170] pc : [<ffffff8008428094>] lr : [<ffffff8008428154>] pstate: a0400145
[   30.833701] sp : ffffffc026f27c50
[   30.841319] x29: ffffffc026f27c50 x28: ffffffc026f27e40
[   30.849634] x27: ffffff8009132000 x26: 0000000000000000
[   30.854932] x25: ffffffc016f0aa80 x24: 0000000000000000
[   30.860224] x23: ffffffc026f27e38 x22: ffffffc026f27d34
[   30.865520] x21: 000000000000000a x20: ffffffc026f27e40
[   30.870818] x19: 000000000000000a x18: 0000007a13b48000
[   30.876118] x17: 0000007a16ca93c0 x16: ffffff8008e56b2c
[   30.881406] x15: 0000000000000020 x14: 002dc6bffa5d9e00
[   30.886701] x13: 203a644974654e4c x12: 00000000000017c1
[   30.891997] x11: 0000000000000000 x10: 0000000000000001
[   30.897292] x9 : 0000000000000002 x8 : ffffff8009933090
[   30.902588] x7 : ffffffc0725fd090 x6 : 0000000004fd9f2c
[   30.907881] x5 : 0000000000000000 x4 : 0000000000000000
[   30.913176] x3 : 00000001ffffffff x2 : 0000000000000000
[   30.918475] x1 : ffffff800a10ca80 x0 : ffffffffffffffe8
some sel_netnode_hash[idx].list==NULL,so happend this.
I add spin_lock_bh on sel_netnode_init.

Signed-off-by: YangHui <yanghui.def@gmail.com>
---
 security/selinux/netnode.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/security/selinux/netnode.c b/security/selinux/netnode.c
index 9ab84ef..aa0eeb7 100644
--- a/security/selinux/netnode.c
+++ b/security/selinux/netnode.c
@@ -293,11 +293,12 @@ static __init int sel_netnode_init(void)
 
 	if (!selinux_enabled)
 		return 0;
-
+	spin_lock_bh(&sel_netnode_lock);
 	for (iter = 0; iter < SEL_NETNODE_HASH_SIZE; iter++) {
 		INIT_LIST_HEAD(&sel_netnode_hash[iter].list);
 		sel_netnode_hash[iter].size = 0;
 	}
+	spin_unlock_bh(&sel_netnode_lock);
 
 	return 0;
 }
-- 
2.7.4