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Date: Mon, 14 Apr 2025 17:55:23 +0100
From: Simon Horman <horms@kernel.org>
To: Sven Eckelmann <sven@narfation.org>
Cc: "David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	b.a.t.m.a.n@lists.open-mesh.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH net v4] batman-adv: Fix double-hold of meshif when
 getting enabled
Message-ID: <20250414165523.GV395307@horms.kernel.org>
References: <20250410-double_hold_fix-v4-1-2f606fe8c204@narfation.org>
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In-Reply-To: <20250410-double_hold_fix-v4-1-2f606fe8c204@narfation.org>

On Thu, Apr 10, 2025 at 08:58:51PM +0200, Sven Eckelmann wrote:
> It was originally meant to replace the dev_hold with netdev_hold. But this
> was missed in batadv_hardif_enable_interface(). As result, there was an
> imbalance and a hang when trying to remove the mesh-interface with
> (previously) active hard-interfaces:
> 
>   unregister_netdevice: waiting for batadv0 to become free. Usage count = 3
> 
> Fixes: 00b35530811f ("batman-adv: adopt netdev_hold() / netdev_put()")
> Signed-off-by: Sven Eckelmann <sven@narfation.org>
> ---
> This patch is skipping Simon's normal PR submission to get this problem
> fixed faster in Linus' tree. This currently creates quite a lot of wrong
> bisect results for syzkaller and it would be better to have this fixed
> sooner than later.
> ---
> Changes in v4:
> - added Suggested-by: Eric Dumazet <edumazet@google.com>
> - added Reported-by: of various syzkaller reports which were affected (during
>   bisecting) by this problem

FWIIW, I don't see those tags at the bottom of the commit message.

> - resubmission after 24h cooldown time
> - added kernel message during hang to commit message
> - Link to v3: https://lore.kernel.org/r/20250409073524.557189-1-sven@narfation.org
> Changes in v3:
> - fix submitter address
> - Link to v2: https://lore.kernel.org/r/20250409073304.556841-1-sw@simonwunderlich.de
> Changes in v2:
> - add missing commit message
> - Link to v1: https://lore.kernel.org/r/20250409073000.556263-1-sven@narfation.org

...