Netdev Archive on lore.kernel.org
 help / color / Atom feed
From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Thomas Pedersen <thomas@eero.com>,
	Johannes Berg <johannes.berg@intel.com>,
	Sasha Levin <sashal@kernel.org>,
	linux-wireless@vger.kernel.org, netdev@vger.kernel.org
Subject: [PATCH AUTOSEL 4.9 04/21] mac80211: mesh: fix RCU warning
Date: Wed, 26 Jun 2019 20:41:04 -0400
Message-ID: <20190627004122.21671-4-sashal@kernel.org> (raw)
In-Reply-To: <20190627004122.21671-1-sashal@kernel.org>

From: Thomas Pedersen <thomas@eero.com>

[ Upstream commit 551842446ed695641a00782cd118cbb064a416a1 ]

ifmsh->csa is an RCU-protected pointer. The writer context
in ieee80211_mesh_finish_csa() is already mutually
exclusive with wdev->sdata.mtx, but the RCU checker did
not know this. Use rcu_dereference_protected() to avoid a
warning.

fixes the following warning:

[   12.519089] =============================
[   12.520042] WARNING: suspicious RCU usage
[   12.520652] 5.1.0-rc7-wt+ #16 Tainted: G        W
[   12.521409] -----------------------------
[   12.521972] net/mac80211/mesh.c:1223 suspicious rcu_dereference_check() usage!
[   12.522928] other info that might help us debug this:
[   12.523984] rcu_scheduler_active = 2, debug_locks = 1
[   12.524855] 5 locks held by kworker/u8:2/152:
[   12.525438]  #0: 00000000057be08c ((wq_completion)phy0){+.+.}, at: process_one_work+0x1a2/0x620
[   12.526607]  #1: 0000000059c6b07a ((work_completion)(&sdata->csa_finalize_work)){+.+.}, at: process_one_work+0x1a2/0x620
[   12.528001]  #2: 00000000f184ba7d (&wdev->mtx){+.+.}, at: ieee80211_csa_finalize_work+0x2f/0x90
[   12.529116]  #3: 00000000831a1f54 (&local->mtx){+.+.}, at: ieee80211_csa_finalize_work+0x47/0x90
[   12.530233]  #4: 00000000fd06f988 (&local->chanctx_mtx){+.+.}, at: ieee80211_csa_finalize_work+0x51/0x90

Signed-off-by: Thomas Pedersen <thomas@eero.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/mac80211/mesh.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c
index b2a27263d6ff..7f902e69530f 100644
--- a/net/mac80211/mesh.c
+++ b/net/mac80211/mesh.c
@@ -1135,7 +1135,8 @@ int ieee80211_mesh_finish_csa(struct ieee80211_sub_if_data *sdata)
 	ifmsh->chsw_ttl = 0;
 
 	/* Remove the CSA and MCSP elements from the beacon */
-	tmp_csa_settings = rcu_dereference(ifmsh->csa);
+	tmp_csa_settings = rcu_dereference_protected(ifmsh->csa,
+					    lockdep_is_held(&sdata->wdev.mtx));
 	RCU_INIT_POINTER(ifmsh->csa, NULL);
 	if (tmp_csa_settings)
 		kfree_rcu(tmp_csa_settings, rcu_head);
@@ -1157,6 +1158,8 @@ int ieee80211_mesh_csa_beacon(struct ieee80211_sub_if_data *sdata,
 	struct mesh_csa_settings *tmp_csa_settings;
 	int ret = 0;
 
+	lockdep_assert_held(&sdata->wdev.mtx);
+
 	tmp_csa_settings = kmalloc(sizeof(*tmp_csa_settings),
 				   GFP_ATOMIC);
 	if (!tmp_csa_settings)
-- 
2.20.1


  parent reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20190627004122.21671-1-sashal@kernel.org>
2019-06-27  0:41 ` [PATCH AUTOSEL 4.9 02/21] samples, bpf: fix to change the buffer size for read() Sasha Levin
2019-06-27  0:41 ` Sasha Levin [this message]
2019-06-27  0:41 ` [PATCH AUTOSEL 4.9 05/21] mac80211: free peer keys before vif down in mesh Sasha Levin
2019-06-27  0:41 ` [PATCH AUTOSEL 4.9 06/21] mwifiex: Fix possible buffer overflows at parsing bss descriptor Sasha Levin
2019-06-27  0:41 ` [PATCH AUTOSEL 4.9 07/21] mwifiex: Abort at too short BSS descriptor element Sasha Levin
2019-06-27  0:41 ` [PATCH AUTOSEL 4.9 08/21] netfilter: ipv6: nf_defrag: fix leakage of unqueued fragments Sasha Levin
2019-06-27  0:41 ` [PATCH AUTOSEL 4.9 09/21] netfilter: ipv6: nf_defrag: accept duplicate fragments again Sasha Levin
2019-06-27  0:41 ` [PATCH AUTOSEL 4.9 10/21] dt-bindings: can: mcp251x: add mcp25625 support Sasha Levin
2019-06-27  0:41 ` [PATCH AUTOSEL 4.9 11/21] can: mcp251x: add support for mcp25625 Sasha Levin
2019-06-27  0:41 ` [PATCH AUTOSEL 4.9 14/21] mlxsw: spectrum: Disallow prio-tagged packets when PVID is removed Sasha Levin
2019-06-27  0:41 ` [PATCH AUTOSEL 4.9 17/21] mac80211: only warn once on chanctx_conf being NULL Sasha Levin
2019-06-27  0:41 ` [PATCH AUTOSEL 4.9 19/21] bnx2x: Check if transceiver implements DDM before access Sasha Levin
2019-06-27  0:41 ` [PATCH AUTOSEL 4.9 20/21] ip6_tunnel: allow not to count pkts on tstats by passing dev as NULL Sasha Levin
2019-06-27  0:41 ` [PATCH AUTOSEL 4.9 21/21] net :sunrpc :clnt :Fix xps refcount imbalance on the error path Sasha Levin

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190627004122.21671-4-sashal@kernel.org \
    --to=sashal@kernel.org \
    --cc=johannes.berg@intel.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-wireless@vger.kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=stable@vger.kernel.org \
    --cc=thomas@eero.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Netdev Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/netdev/0 netdev/git/0.git
	git clone --mirror https://lore.kernel.org/netdev/1 netdev/git/1.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 netdev netdev/ https://lore.kernel.org/netdev \
		netdev@vger.kernel.org netdev@archiver.kernel.org
	public-inbox-index netdev


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.netdev


AGPL code for this site: git clone https://public-inbox.org/ public-inbox