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1524b12a6e
The mkey_table xarray is touched by the reg_mr_callback() function which
is called from a hard irq. Thus all other uses of xa_lock must use the
_irq variants.
WARNING: inconsistent lock state
5.4.0-rc1 #12 Not tainted
--------------------------------
inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
python3/343 [HC0[0]:SC0[0]:HE1:SE1] takes:
ffff888182be1d40 (&(&xa->xa_lock)->rlock#3){?.-.}, at: xa_erase+0x12/0x30
{IN-HARDIRQ-W} state was registered at:
lock_acquire+0xe1/0x200
_raw_spin_lock_irqsave+0x35/0x50
reg_mr_callback+0x2dd/0x450 [mlx5_ib]
mlx5_cmd_exec_cb_handler+0x2c/0x70 [mlx5_core]
mlx5_cmd_comp_handler+0x355/0x840 [mlx5_core]
[..]
Possible unsafe locking scenario:
CPU0
----
lock(&(&xa->xa_lock)->rlock#3);
<Interrupt>
lock(&(&xa->xa_lock)->rlock#3);
*** DEADLOCK ***
2 locks held by python3/343:
#0: ffff88818eb4bd38 (&uverbs_dev->disassociate_srcu){....}, at: ib_uverbs_ioctl+0xe5/0x1e0 [ib_uverbs]
#1: ffff888176c76d38 (&file->hw_destroy_rwsem){++++}, at: uobj_destroy+0x2d/0x90 [ib_uverbs]
stack backtrace:
CPU: 3 PID: 343 Comm: python3 Not tainted 5.4.0-rc1 #12
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
Call Trace:
dump_stack+0x86/0xca
print_usage_bug.cold.50+0x2e5/0x355
mark_lock+0x871/0xb50
? match_held_lock+0x20/0x250
? check_usage_forwards+0x240/0x240
__lock_acquire+0x7de/0x23a0
? __kasan_check_read+0x11/0x20
? mark_lock+0xae/0xb50
? mark_held_locks+0xb0/0xb0
? find_held_lock+0xca/0xf0
lock_acquire+0xe1/0x200
? xa_erase+0x12/0x30
_raw_spin_lock+0x2a/0x40
? xa_erase+0x12/0x30
xa_erase+0x12/0x30
mlx5_ib_dealloc_mw+0x55/0xa0 [mlx5_ib]
uverbs_dealloc_mw+0x3c/0x70 [ib_uverbs]
uverbs_free_mw+0x1a/0x20 [ib_uverbs]
destroy_hw_idr_uobject+0x49/0xa0 [ib_uverbs]
[..]
Fixes: 0417791536 ("RDMA/mlx5: Add missing synchronize_srcu() for MW cases")
Link: https://lore.kernel.org/r/20191024234910.GA9038@ziepe.ca
Acked-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
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.