From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sipsolutions.net (s3.sipsolutions.net [168.119.38.16]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D411E3B27D5; Wed, 20 May 2026 08:58:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=168.119.38.16 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779267520; cv=none; b=Gv86gNLz8rnz/OyWbcsflXNeRboBOeni7orzhKvGXPu7eLnyXWp5qZAY+lnysSQBqg4d3/DcPdwYL2sfTFA2QkkX9h/z599nsr4ah+HQ7RL1YSN1WrsvIaUwtTxTio67bAbWJgLEw3G3PRKqAuCw8ZLnA2bCYampLeqkblUewXE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779267520; c=relaxed/simple; bh=C7c7KpWnigi7II5FEvk/eOPvVHrwTYsrna6FOHAYA+4=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=VgJlUybTFn7LMCuxUR/EsLGg3Y84nhVWr4H1vrz554lKnpLaoP+aZ2+0xailORiklaIkChRSchaCQFPgYFacGdFwxvWOiPOT4zzRopZPV1sjM/KucsO8q332FSf95uWaMcj4J+9BnWLb7ZiHTfCsqVZtVFVvWKGaolwewLHnMvs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=permerror header.from=sipsolutions.net; spf=none smtp.mailfrom=sipsolutions.net; dkim=pass (2048-bit key) header.d=sipsolutions.net header.i=@sipsolutions.net header.b=xHMuVhFV; arc=none smtp.client-ip=168.119.38.16 Authentication-Results: smtp.subspace.kernel.org; dmarc=permerror header.from=sipsolutions.net Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=sipsolutions.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=sipsolutions.net header.i=@sipsolutions.net header.b="xHMuVhFV" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sipsolutions.net; s=mail; h=MIME-Version:Content-Transfer-Encoding: Content-Type:References:In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-To: Resent-Cc:Resent-Message-ID; bh=0kNSpQkTH2BddyvatsQSQRab4uR59/gfZ0Rx4WHQy+g=; t=1779267517; x=1780477117; b=xHMuVhFVFChkeBpNanpV4asMtDBKUXBYXL97KgGx42psIh+ IJPqmk2oSw6hbCFaUMaDqzOTVlOjbB0LBJOdI5NRGBVua1syRNjVWi2nDMHCfFA3yJh239LPsfpqI TxEO85jH5aHbxpZ1MeZu1zjhLCkUUPqd1xXGXcGuDVFL1/qABExIocitRpqx37+qMUw9u3unD3l47 PKtv1I6i7v6C9iE/F/35KecMUCLmxGhOvR+MnYuGU1+U5BQ5IdF7lTMd72mhdHlAFNYSsQ4sgY2KE 56bmjt+ht5WKawIMVWhcrh9t6pFsbwtqBWKL7c6FRU3zgZL9MnIQqZE4UR+Btfsw==; Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.98.2) (envelope-from ) id 1wPcl4-0000000A19z-4AXW; Wed, 20 May 2026 10:58:31 +0200 Message-ID: <739ba20fa3c88e92bf034d80383015b8bc78ebfe.camel@sipsolutions.net> Subject: Re: [PATCH v4] wifi: mac80211: fix monitor mode frame capture for real chanctx drivers From: Johannes Berg To: =?ISO-8859-1?Q?=D3scar?= Alfonso =?ISO-8859-1?Q?D=EDaz?= Cc: Devin Wittmayer , linux-wireless@vger.kernel.org, Felix Fietkau , Lorenzo Bianconi , linux-kernel@vger.kernel.org, stable@vger.kernel.org, fjhhz1997@gmail.com, Brite Date: Wed, 20 May 2026 10:58:29 +0200 In-Reply-To: (sfid-20260520_100244_085590_6B2EF659) References: <20260518170147.13885-1-lucid_duck@justthetip.ca> <20260519235713.49109-1-lucid_duck@justthetip.ca> <20260519235713.49109-2-lucid_duck@justthetip.ca> (sfid-20260520_100244_085590_6B2EF659) Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.58.3 (3.58.3-1.fc43) Precedence: bulk X-Mailing-List: linux-wireless@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-malware-bazaar: not-scanned On Wed, 2026-05-20 at 10:02 +0200, =C3=93scar Alfonso D=C3=ADaz wrote: > I tested it on 6.18.12 >=20 > Let me know if you need me to test it again or whatever. I remember > during my testing with the Brite's different patches that is not the > same testing it on 6.18.x than 6.19 . Some stuff changed and the patch > needed to be different. I've added Brite to the thread, he can add > more useful data for you. I guess I don't really care about 6.18.x or 6.19.x, only about 7.1-rcX at this point. We'll want to explicitly _not_ backport this fix to older kernel versions since it caused driver crashes. > Regarding the approach of fixing the bug on the driver side... I've > emailed and contacted by IRC to Lorenzo explaining the problem... but > I got no response. So if we feel yet like this is something that needs > to be fixed from the "driver side"... how to say it softly... we are > f***ed up :) . Maybe the "hack" way dealing with the vif null var is > not bad idea after all as it seems the only way to move forward. I feel I've tried to say this before, but maybe it helps if I summarise: There's one feature and one (possible) bug here. The feature is: - monitor mode injection works for chanctx drivers. The bug is: - monitor mode injection with the feature patch crashes at least some mt76 devices, which you reported, which I consider to be a bug in the driver that needs to be fixed there. To me, the trade-off is crystal clear - as long as the bug exists, I'm not going to apply this or a similar patch to enable the feature. I'm also not going to apply a patch like proposed before that hacks it by redirecting the vif pointer to a (more or less random) other vif, that's a lazy hack that happens to fix the problem in your _specific_ use case, but will almost certainly still expose the crash in other use cases. I do think there's a chance that between 6.18/6.19 and 7.1-rcX the bug in the driver has already been fixed, that's why I keep asking about versions etc. But I also think there's a chance you're just testing different subdrivers of mt76 with different devices, so I'm also asking you to compare the specific devices. I'm happy to apply this patch if the people who previously reported it to crash (i.e. mostly you, not sure about others) are saying that against a more recent kernel it no longer causes the test to crash (rather than just not work, which is clearly better than crashing.) You could always just claim you've tested this patch without the crash and I'll apply it, but then if someone still finds a crash I'm just going to have to revert it, and we'd be back to square one. I hope this explains what I'm thinking and going to do (and not do), make of it what you will. johannes