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author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2021-11-26 17:15:29 +0100 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-06-29 09:03:22 +0200 |
commit | f617cef465523e453ea3df4e87cb8e02c3efbace (patch) | |
tree | 06e090a58c21f3ef62205352ca1a6053a78fa7ff /net/hsr | |
parent | 638be56ae9cc5c25a81c525df20b1b9d92b08613 (diff) | |
download | linux-stable-f617cef465523e453ea3df4e87cb8e02c3efbace.tar.gz linux-stable-f617cef465523e453ea3df4e87cb8e02c3efbace.tar.bz2 linux-stable-f617cef465523e453ea3df4e87cb8e02c3efbace.zip |
net: Write lock dev_base_lock without disabling bottom halves.
[ Upstream commit fd888e85fe6b661e78044dddfec0be5271afa626 ]
The writer acquires dev_base_lock with disabled bottom halves.
The reader can acquire dev_base_lock without disabling bottom halves
because there is no writer in softirq context.
On PREEMPT_RT the softirqs are preemptible and local_bh_disable() acts
as a lock to ensure that resources, that are protected by disabling
bottom halves, remain protected.
This leads to a circular locking dependency if the lock acquired with
disabled bottom halves (as in write_lock_bh()) and somewhere else with
enabled bottom halves (as by read_lock() in netstat_show()) followed by
disabling bottom halves (cxgb_get_stats() -> t4_wr_mbox_meat_timeout()
-> spin_lock_bh()). This is the reverse locking order.
All read_lock() invocation are from sysfs callback which are not invoked
from softirq context. Therefore there is no need to disable bottom
halves while acquiring a write lock.
Acquire the write lock of dev_base_lock without disabling bottom halves.
Reported-by: Pei Zhang <pezhang@redhat.com>
Reported-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'net/hsr')
-rw-r--r-- | net/hsr/hsr_device.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/net/hsr/hsr_device.c b/net/hsr/hsr_device.c index 26c32407f029..ea7b96e296ef 100644 --- a/net/hsr/hsr_device.c +++ b/net/hsr/hsr_device.c @@ -30,13 +30,13 @@ static bool is_slave_up(struct net_device *dev) static void __hsr_set_operstate(struct net_device *dev, int transition) { - write_lock_bh(&dev_base_lock); + write_lock(&dev_base_lock); if (dev->operstate != transition) { dev->operstate = transition; - write_unlock_bh(&dev_base_lock); + write_unlock(&dev_base_lock); netdev_state_change(dev); } else { - write_unlock_bh(&dev_base_lock); + write_unlock(&dev_base_lock); } } |