6323514116
mlx5e_vxlan_lookup_port is called both from mlx5e_add_vxlan_port (user
context) and mlx5e_features_check (softirq), but the lock acquired does
not disable bottom half and might result in deadlock. Fix it by simply
replacing spin_lock() with spin_lock_bh().
While at it, replace all unnecessary spin_lock_irq() to spin_lock_bh().
lockdep's WARNING: inconsistent lock state
[ 654.028136] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
[ 654.028229] swapper/5/0 [HC0[0]:SC1[9]:HE1:SE0] takes:
[ 654.028321] (&(&vxlan_db->lock)->rlock){+.?.}, at: [<ffffffffa06e7f0e>] mlx5e_vxlan_lookup_port+0x1e/0x50 [mlx5_core]
[ 654.028528] {SOFTIRQ-ON-W} state was registered at:
[ 654.028607] _raw_spin_lock+0x3c/0x70
[ 654.028689] mlx5e_vxlan_lookup_port+0x1e/0x50 [mlx5_core]
[ 654.028794] mlx5e_vxlan_add_port+0x2e/0x120 [mlx5_core]
[ 654.028878] process_one_work+0x1e9/0x640
[ 654.028942] worker_thread+0x4a/0x3f0
[ 654.029002] kthread+0x141/0x180
[ 654.029056] ret_from_fork+0x24/0x30
[ 654.029114] irq event stamp: 579088
[ 654.029174] hardirqs last enabled at (579088): [<ffffffff818f475a>] ip6_finish_output2+0x49a/0x8c0
[ 654.029309] hardirqs last disabled at (579087): [<ffffffff818f470e>] ip6_finish_output2+0x44e/0x8c0
[ 654.029446] softirqs last enabled at (579030): [<ffffffff810b3b3d>] irq_enter+0x6d/0x80
[ 654.029567] softirqs last disabled at (579031): [<ffffffff810b3c05>] irq_exit+0xb5/0xc0
[ 654.029684] other info that might help us debug this:
[ 654.029781] Possible unsafe locking scenario:
[ 654.029868] CPU0
[ 654.029908] ----
[ 654.029947] lock(&(&vxlan_db->lock)->rlock);
[ 654.030045] <Interrupt>
[ 654.030090] lock(&(&vxlan_db->lock)->rlock);
[ 654.030162]
*** DEADLOCK ***
Fixes: b3f63c3d5e2c ("net/mlx5e: Add netdev support for VXLAN tunneling")
Signed-off-by: Gal Pressman <galp@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.