From: Tariq Toukan <tariqt@mellanox.com>
To: "David S. Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org, Eran Ben Elisha <eranbe@mellanox.com>,
Tariq Toukan <tariqt@mellanox.com>,
Jesper Dangaard Brouer <brouer@redhat.com>
Subject: [PATCH net] net/xdp: Fix suspicious RCU usage warning
Date: Tue, 17 Jul 2018 18:10:38 +0300 [thread overview]
Message-ID: <1531840238-30818-2-git-send-email-tariqt@mellanox.com> (raw)
In-Reply-To: <1531840238-30818-1-git-send-email-tariqt@mellanox.com>
Fix the warning below by calling rhashtable_lookup under
RCU read lock.
[ 342.450870] WARNING: suspicious RCU usage
[ 342.455856] 4.18.0-rc2+ #17 Tainted: G O
[ 342.462210] -----------------------------
[ 342.467202] ./include/linux/rhashtable.h:481 suspicious rcu_dereference_check() usage!
[ 342.476568]
[ 342.476568] other info that might help us debug this:
[ 342.476568]
[ 342.486978]
[ 342.486978] rcu_scheduler_active = 2, debug_locks = 1
[ 342.495211] 4 locks held by modprobe/3934:
[ 342.500265] #0: 00000000e23116b2 (mlx5_intf_mutex){+.+.}, at:
mlx5_unregister_interface+0x18/0x90 [mlx5_core]
[ 342.511953] #1: 00000000ca16db96 (rtnl_mutex){+.+.}, at: unregister_netdev+0xe/0x20
[ 342.521109] #2: 00000000a46e2c4b (&priv->state_lock){+.+.}, at: mlx5e_close+0x29/0x60
[mlx5_core]
[ 342.531642] #3: 0000000060c5bde3 (mem_id_lock){+.+.}, at: xdp_rxq_info_unreg+0x93/0x6b0
[ 342.541206]
[ 342.541206] stack backtrace:
[ 342.547075] CPU: 12 PID: 3934 Comm: modprobe Tainted: G O 4.18.0-rc2+ #17
[ 342.556621] Hardware name: Dell Inc. PowerEdge R730/0H21J3, BIOS 1.5.4 10/002/2015
[ 342.565606] Call Trace:
[ 342.568861] dump_stack+0x78/0xb3
[ 342.573086] xdp_rxq_info_unreg+0x3f5/0x6b0
[ 342.578285] ? __call_rcu+0x220/0x300
[ 342.582911] mlx5e_free_rq+0x38/0xc0 [mlx5_core]
[ 342.588602] mlx5e_close_channel+0x20/0x120 [mlx5_core]
[ 342.594976] mlx5e_close_channels+0x26/0x40 [mlx5_core]
[ 342.601345] mlx5e_close_locked+0x44/0x50 [mlx5_core]
[ 342.607519] mlx5e_close+0x42/0x60 [mlx5_core]
[ 342.613005] __dev_close_many+0xb1/0x120
[ 342.617911] dev_close_many+0xa2/0x170
[ 342.622622] rollback_registered_many+0x148/0x460
[ 342.628401] ? __lock_acquire+0x48d/0x11b0
[ 342.633498] ? unregister_netdev+0xe/0x20
[ 342.638495] rollback_registered+0x56/0x90
[ 342.643588] unregister_netdevice_queue+0x7e/0x100
[ 342.649461] unregister_netdev+0x18/0x20
[ 342.654362] mlx5e_remove+0x2a/0x50 [mlx5_core]
[ 342.659944] mlx5_remove_device+0xe5/0x110 [mlx5_core]
[ 342.666208] mlx5_unregister_interface+0x39/0x90 [mlx5_core]
[ 342.673038] cleanup+0x5/0xbfc [mlx5_core]
[ 342.678094] __x64_sys_delete_module+0x16b/0x240
[ 342.683725] ? do_syscall_64+0x1c/0x210
[ 342.688476] do_syscall_64+0x5a/0x210
[ 342.693025] entry_SYSCALL_64_after_hwframe+0x49/0xbe
Fixes: 8d5d88527587 ("xdp: rhashtable with allocator ID to pointer mapping")
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
---
net/core/xdp.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 9d1f22072d5d..c20fefbfb76c 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -102,7 +102,9 @@ static void __xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq)
mutex_lock(&mem_id_lock);
+ rcu_read_lock();
xa = rhashtable_lookup(mem_id_ht, &id, mem_id_rht_params);
+ rcu_read_unlock();
if (!xa) {
mutex_unlock(&mem_id_lock);
return;
--
1.8.3.1
next prev parent reply other threads:[~2018-07-17 15:53 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-17 15:10 [PATCH net] net/page_pool: Fix inconsistent lock state warning Tariq Toukan
2018-07-17 15:10 ` Tariq Toukan [this message]
2018-07-17 16:47 ` [PATCH net] net/xdp: Fix suspicious RCU usage warning Alexei Starovoitov
2018-07-17 19:27 ` Daniel Borkmann
2018-07-18 14:13 ` Tariq Toukan
2018-07-19 21:36 ` Alexei Starovoitov
2018-08-12 8:45 ` Tariq Toukan
2018-08-12 23:04 ` Daniel Borkmann
2018-07-20 6:23 ` [PATCH net] net/page_pool: Fix inconsistent lock state warning David Miller
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