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Date: Tue, 13 Jan 2026 13:26:49 +0000
From: Simon Horman <horms@kernel.org>
To: Lorenzo Bianconi <lorenzo@kernel.org>
Cc: Andrew Lunn <andrew+netdev@lunn.ch>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-mediatek@lists.infradead.org, netdev@vger.kernel.org
Subject: Re: [PATCH net v2] net: airoha: Fix schedule while atomic in
 airoha_ppe_deinit()
Message-ID: <aWZIGbwN1fdHCgnb@horms.kernel.org>
References: <20260105-airoha-fw-ethtool-v2-1-3b32b158cc31@kernel.org>
 <20260108132218.GG345651@kernel.org>
 <aWDLg6RzI4s2VgIH@lore-desk>
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In-Reply-To: <aWDLg6RzI4s2VgIH@lore-desk>

On Fri, Jan 09, 2026 at 10:33:55AM +0100, Lorenzo Bianconi wrote:
> > On Mon, Jan 05, 2026 at 09:43:31AM +0100, Lorenzo Bianconi wrote:
> > > airoha_ppe_deinit() runs airoha_npu_ppe_deinit() in atomic context.
> > > airoha_npu_ppe_deinit routine allocates ppe_data buffer with GFP_KERNEL
> > > flag. Rely on rcu_replace_pointer in airoha_ppe_deinit routine in order
> > > to fix schedule while atomic issue in airoha_npu_ppe_deinit() since we
> > > do not need atomic context there.
> > 
> > Hi Lorenzo,
> 
> Hi Simon,
> 
> > 
> > If I understand things correctly the key problem here is that
> > an allocation with GFP_KERNEL implies GFP_RECLAIM and thus may sleep.
> > But RCU read-side critical sections are not allowed to sleep in non-RT
> > kernels.
> 
> yes, right, RCU section is atomic.
> 
> > 
> > If so, I think it would be clearer to describe the problem along those
> > lines. But maybe it is just me.
> 
> This patch is already in Linus's tree.

Yeah, sorry for missing that.