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 4.4 03/12] mac80211: mesh: fix RCU warning
Date: Wed, 26 Jun 2019 20:42:25 -0400 [thread overview]
Message-ID: <20190627004236.21909-3-sashal@kernel.org> (raw)
In-Reply-To: <20190627004236.21909-1-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 1cbc7bd26de3..4bd8f3f056d8 100644
--- a/net/mac80211/mesh.c
+++ b/net/mac80211/mesh.c
@@ -1138,7 +1138,8 @@ 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);
@@ -1160,6 +1161,8 @@ 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
next prev parent reply other threads:[~2019-06-27 0:42 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190627004236.21909-1-sashal@kernel.org>
2019-06-27 0:42 ` [PATCH AUTOSEL 4.4 02/12] samples, bpf: fix to change the buffer size for read() Sasha Levin
2019-06-27 0:42 ` Sasha Levin [this message]
2019-06-27 0:42 ` [PATCH AUTOSEL 4.4 04/12] mwifiex: Fix possible buffer overflows at parsing bss descriptor Sasha Levin
2019-06-27 0:42 ` [PATCH AUTOSEL 4.4 05/12] mwifiex: Abort at too short BSS descriptor element Sasha Levin
2019-06-27 0:42 ` [PATCH AUTOSEL 4.4 06/12] dt-bindings: can: mcp251x: add mcp25625 support Sasha Levin
2019-06-27 0:42 ` [PATCH AUTOSEL 4.4 07/12] can: mcp251x: add support for mcp25625 Sasha Levin
2019-06-27 0:42 ` [PATCH AUTOSEL 4.4 12/12] bnx2x: Check if transceiver implements DDM before access Sasha Levin
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