Re: [PATCH 1/2] RDMA/ionic: Fix XArray initialization to use XArray flags

[sashiko-bot@kernel.org]

> xa_init_flags() takes XArray flags (XA_FLAGS_*), not gfp flags, even
> though the parameter is typed gfp_t. Passing GFP_ATOMIC leaves both
> lock-type bits clear, so xa_lock_type() resolves to XA_LOCK_NORMAL for
> qp_tbl and cq_tbl.
> 
> Both tables are used with the IRQ-safe accessors: xa_store_irq() with
> GFP_KERNEL from process context, and xa_lock_irqsave() from the event
> queue path. When a store needs to grow the tree, __xas_nomem() drops
> the lock using the recorded lock type before allocating:
> 
> 	if (gfpflags_allow_blocking(gfp)) {
> 		xas_unlock_type(xas, lock_type);
> 		xas->xa_alloc = kmem_cache_alloc_lru(...);
> 		xas_lock_type(xas, lock_type);
> 	}
> 
> With XA_LOCK_NORMAL that is a plain spin_unlock(), so the sleeping
> GFP_KERNEL allocation runs with interrupts still disabled by
> xa_store_irq(), and lockdep annotates the lock with the wrong class.
> 
> GFP_ATOMIC also happens to set __GFP_HIGH (0x20), which collides with
> XA_FLAGS_ACCOUNT (32U) and silently enables memcg accounting of the
> XArray nodes.
> 
> Use XA_FLAGS_LOCK_IRQ so the lock type matches how the tables are
> actually accessed.
> 
> Fixes: e8521822c733 ("RDMA/ionic: Register device ops for control path")
> Signed-off-by: Abhijit Gangurde <abhijit.gangurde@amd.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260925093638.3032149-1-abhijit.gangurde@amd.com?part=1