Re: [PATCH rdma-rc] RDMA/mlx5: Fix unsafe xarray access in implicit ODP handling

[Jason Gunthorpe <jgg@nvidia.com>]

On Mon, Jun 16, 2025 at 11:17:01AM +0300, Leon Romanovsky wrote:
> From: Or Har-Toov <ohartoov@nvidia.com>
> 
> __xa_store() and __xa_erase() were used without holding the proper lock,
> which led to a lockdep warning due to unsafe RCPU usage.
> This patch replaces them with xa_store() and xa_erase(), which perform
> the necessary locking internally.
> 
> =============================
> WARNING: suspicious RCPU usage
> 6.14.0-rc7_for_upstream_debug_2025_03_18_15_01 #1 Not tainted
> -----------------------------
> ./include/linux/xarray.h:1211 suspicious rcu_dereference_protected()
> usage!
> 
> other info that might help us debug this:
> 
> rcu_scheduler_active = 2, debug_locks = 1
> 3 locks held by kworker/u136:0/219:
>     at: process_one_work+0xbe4/0x15f0
>     process_one_work+0x75c/0x15f0
>     pagefault_mr+0x9a5/0x1390 [mlx5_ib]
> 
> stack backtrace:
> CPU: 14 UID: 0 PID: 219 Comm: kworker/u136:0 Not tainted
> 6.14.0-rc7_for_upstream_debug_2025_03_18_15_01 #1
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS
> rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
> Workqueue: mlx5_ib_page_fault mlx5_ib_eqe_pf_action [mlx5_ib]
> Call Trace:

Don't work wrap oops messages.. Ignore the checkpatch thing that tells
you to do that.

Applied to for-rc

Thanks,
Jason