Re: suspicious RCU usage in xfrm_net_init()
From: Fengguang Wu <hidden>
Date: 2012-08-16 15:20:01
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Hi Fan, On Thu, Aug 16, 2012 at 05:36:35PM +0800, Fan Du wrote:
Hi, Fengguang Could you please try the below patch, see if spewing still there? thanks
Yes, it worked, thank you very much! btw, your email client wraps long lines.. Thanks, Fengguang
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From a3f86ecc3ee16ff81d49416bbf791780422988b3 Mon Sep 17 00:00:00 2001 From: Fan Du <redacted> Date: Thu, 16 Aug 2012 17:31:25 +0800 Subject: [PATCH] Use rcu_dereference_bh to deference pointer protected by rcu_read_lock_bh Signed-off-by: Fan Du <redacted> --- net/xfrm/xfrm_policy.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index 5ad4d2c..75a9d6a 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c@@ -2501,7 +2501,7 @@ static void __net_initxfrm_dst_ops_init(struct net *net) struct xfrm_policy_afinfo *afinfo; rcu_read_lock_bh(); - afinfo = rcu_dereference(xfrm_policy_afinfo[AF_INET]); + afinfo = rcu_dereference_bh(xfrm_policy_afinfo[AF_INET]); if (afinfo) net->xfrm.xfrm4_dst_ops = *afinfo->dst_ops; #if IS_ENABLED(CONFIG_IPV6) -- 1.7.1 On 2012年08月16日 15:37, Fengguang Wu wrote:quoted
Hi Priyanka, The below warning shows up, probably related to this commit: 418a99ac6ad487dc9c42e6b0e85f941af56330f2 Replace rwlock on xfrm_policy_afinfo with rcu [ 0.921216] [ 0.921645] =============================== [ 0.922766] [ INFO: suspicious RCU usage. ] [ 0.923887] 3.5.0-01540-g1669891 #64 Not tainted [ 0.925123] ------------------------------- [ 0.932860] /c/kernel-tests/src/tip/net/xfrm/xfrm_policy.c:2504 suspicious rcu_dereference_check() usage! [ 0.935361] [ 0.935361] other info that might help us debug this: [ 0.935361] [ 0.937472] [ 0.937472] rcu_scheduler_active = 1, debug_locks = 0 [ 0.939182] 2 locks held by swapper/1: [ 0.940171] #0: (net_mutex){+.+.+.}, at: [<ffffffff814e1ad0>] register_pernet_subsys+0x21/0x57 [ 0.942705] #1: (rcu_read_lock_bh){......}, at: [<ffffffff822c7329>] xfrm_net_init+0x1e4/0x437 [ 0.951507] [ 0.951507] stack backtrace: [ 0.952660] Pid: 1, comm: swapper Not tainted 3.5.0-01540-g1669891 #64 [ 0.954364] Call Trace: [ 0.955074] [<ffffffff8108b375>] lockdep_rcu_suspicious+0x174/0x187 [ 0.956736] [<ffffffff822c7453>] xfrm_net_init+0x30e/0x437 [ 0.958205] [<ffffffff822c7329>] ? xfrm_net_init+0x1e4/0x437 [ 0.959712] [<ffffffff814e134a>] ops_init+0x1bb/0x1ff [ 0.961067] [<ffffffff810861f9>] ? trace_hardirqs_on+0x1b/0x24 [ 0.962644] [<ffffffff814e17cd>] register_pernet_operations.isra.5+0x9d/0xfe [ 0.971376] [<ffffffff814e1adf>] register_pernet_subsys+0x30/0x57 [ 0.972992] [<ffffffff822c7130>] xfrm_init+0x17/0x2c [ 0.974316] [<ffffffff822c2f8c>] ip_rt_init+0x82/0xe7 [ 0.975668] [<ffffffff822c31dc>] ip_init+0x10/0x25 [ 0.976952] [<ffffffff822c3f77>] inet_init+0x235/0x360 [ 0.978352] [<ffffffff822c3d42>] ? devinet_init+0xf2/0xf2 [ 0.979808] [<ffffffff82283252>] do_one_initcall+0xb4/0x203 [ 0.981313] [<ffffffff8228354a>] kernel_init+0x1a9/0x29a [ 0.982732] [<ffffffff822826d9>] ? loglevel+0x46/0x46 [ 0.990889] [<ffffffff816d3d84>] kernel_thread_helper+0x4/0x10 [ 0.992472] [<ffffffff816d262c>] ? retint_restore_args+0x13/0x13 [ 0.994076] [<ffffffff822833a1>] ? do_one_initcall+0x203/0x203 [ 0.995636] [<ffffffff816d3d80>] ? gs_change+0x13/0x13 [ 0.997197] TCP established hash table entries: 8192 (order: 5, 131072 bytes) [ 1.000074] TCP bind hash table entries: 8192 (order: 7, 655360 bytes) Thanks, Fengguang-- Love each day! --fan