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From: Simon Horman <horms@kernel.org>
To: Yang Zi <2959243019@qq.com>
Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
	pabeni@redhat.com, andrew+netdev@lunn.ch, kees@kernel.org,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: liquidio: avoid sleeping allocation under octeon_devices_lock
Date: Wed, 2 Sep 2026 16:54:23 +0100	[thread overview]
Message-ID: <20260902155423.GG396647@horms.kernel.org> (raw)
In-Reply-To: <tencent_6653AA61B6BB17B8D845A89977D199C08C06@qq.com>

On Tue, Aug 25, 2026 at 04:50:55PM +0800, Yang Zi wrote:
> octeon_allocate_device() holds the spinlock octeon_devices_lock while
> calling octeon_allocate_device_mem(), which uses vzalloc(). vzalloc()
> can sleep, so this is a "scheduling while atomic" bug that can trigger a
> sleeping-in-atomic warning (or deadlock on a preemptible kernel).
> 
> The memory allocation does not touch octeon_device[], octeon_device_count
> or the free-slot search, so it does not need the lock. Move the
> octeon_allocate_device_mem() call ahead of the lock: allocate the device
> memory first, then take the lock only to find a free slot and register
> the new device in the octeon_device[] array. If no slot is available
> (all MAX_OCTEON_DEVICES slots in use), free the freshly allocated memory
> and return NULL as before.
> 
> The lock therefore continues to protect exactly the data it documents:
> the octeon_device[] array and octeon_device_count.
> 
> Signed-off-by: Yang Zi <2959243019@qq.com>

This patch has been marked as Not Applicable in patchwork.
I assume that is because it doesn't apply.
Which I believe, in turn, is because it is whitespace mangled:
the tabs appear to have been substituted for combinations
of spaces and non-breaking spaces.

Please consider updating the way that you send patches -
e.g. using b4 or a different mail server - and reposting.

  reply	other threads:[~2026-09-02 15:54 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-25  8:50 [PATCH] net: liquidio: avoid sleeping allocation under octeon_devices_lock Yang Zi
2026-09-02 15:54 ` Simon Horman [this message]
2026-09-03  0:58   ` Jakub Kicinski
2026-09-03 10:28     ` Simon Horman

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