netdev - Re: [PATCH net v2] net: airoha: Fix schedule while atomic in airoha_ppe

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Message-ID: <aWDLg6RzI4s2VgIH@lore-desk>
Date: Fri, 9 Jan 2026 10:33:55 +0100
From: Lorenzo Bianconi <lorenzo@...nel.org>
To: Simon Horman <horms@...nel.org>
Cc: Andrew Lunn <andrew+netdev@...n.ch>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	linux-arm-kernel@...ts.infradead.org,
	linux-mediatek@...ts.infradead.org, netdev@...r.kernel.org
Subject: Re: [PATCH net v2] net: airoha: Fix schedule while atomic in
 airoha_ppe_deinit()

> 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.

Regards,
Lorenzo

> 
> > 
> > Fixes: 00a7678310fe3 ("net: airoha: Introduce flowtable offload support")
> > Signed-off-by: Lorenzo Bianconi <lorenzo@...nel.org>
> > ---
> > Changes in v2:
> > - Update commit log.
> > - Link to v1: https://lore.kernel.org/r/20251223-airoha-fw-ethtool-v1-1-1dbd1568c585@kernel.org
> 
> ...

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