Re: [PATCH] ath11k: acquire ab->base_lock in unassign when finding the peer by addr

From: Kalle Valo <kvalo@kernel.org>
To: Niels Dossche <dossche.niels@gmail.com>
Cc: ath11k@lists.infradead.org, linux-wireless@vger.kernel.org,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Carl Huang <cjhuang@codeaurora.org>
Subject: Re: [PATCH] ath11k: acquire ab->base_lock in unassign when finding the peer by addr
Date: Wed, 16 Mar 2022 16:34:19 +0200	[thread overview]
Message-ID: <87k0cuotjo.fsf@kernel.org> (raw)
In-Reply-To: <c0874b06-116d-7471-3b50-21099c729c3d@gmail.com> (Niels Dossche's message of "Wed, 16 Mar 2022 11:43:30 +0100")

Niels Dossche <dossche.niels@gmail.com> writes:

> On 3/16/22 07:13, Kalle Valo wrote:
>> Niels Dossche <dossche.niels@gmail.com> writes:
>> 
>>> ath11k_peer_find_by_addr states via lockdep that ab->base_lock must be
>>> held when calling that function in order to protect the list. All
>>> callers except ath11k_mac_op_unassign_vif_chanctx have that lock
>>> acquired when calling ath11k_peer_find_by_addr. That lock is also not
>>> transitively held by a path towards ath11k_mac_op_unassign_vif_chanctx.
>>> The solution is to acquire the lock when calling
>>> ath11k_peer_find_by_addr inside ath11k_mac_op_unassign_vif_chanctx.
>>>
>>> Fixes: 701e48a43e15 ("ath11k: add packet log support for QCA6390")
>>> Signed-off-by: Niels Dossche <dossche.niels@gmail.com>
>> 
>> On what hardware and firmware version did you test this?
>> 
>
> Thanks for your reply.
> I am currently working on a static analyser to detect missing locks.
> This was a reported case. I manually verified the report by looking
> at the code, so that I do not send wrong information or patches.
> After concluding that this seems to be a true positive, I created this patch.
> However, as I do not in fact have this particular hardware, I was unable to test it.

Ah, I didn't realise this. If you are using a tool to find errors in the
code it's always a good idea to document that in the commit log. I'll
add an edited version of what wrote you above in the commit log, ok?

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