From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 682E3131748; Tue, 23 Jan 2024 00:24:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705969449; cv=none; b=dgrS0R2pQnFj82krK4UKgOyTKGoqbjdC88kjKPz6OAEvLazP9LGemALorIZOMgadjRHuJaUbGz4gJYaiFul2r8AzgIbATWehD641jN/429P1MRWixVCOTQ4/kgJVnZdNthlopAiol5GNL0dUD5n/fkPKs5L/jNAfgOXjUNqe0pQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705969449; c=relaxed/simple; bh=VqU16vs751sl3MpltP4VM0gTEC6ceVkGcPlts/SkR4c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Vcjed1fKpNDEcE/Ax1TZ58IGs1TvU0s/f47eWikhFx41ZucBFLY41lFk1yjyZb/Btp/hl5WxnGae3M+2pBq7U7wD1KqF8P90XOj0BV6EOaiIB6INAf2MVJu8MCvPzbK4UvI5L5RpKWRaNOYEByzm+UxT1dEkYTyrsxAZ7vq89VY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=d7X09Pqi; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="d7X09Pqi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EACD2C43390; Tue, 23 Jan 2024 00:24:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1705969449; bh=VqU16vs751sl3MpltP4VM0gTEC6ceVkGcPlts/SkR4c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=d7X09PqipuoOHRXkWzNyZbYqyFF43472aMC5YIxYmoF2RS8udwTMm0WZC2xu7bWYn T0XbCrgw2aHQhT/cFIzpW76WaD8/nLr9ohq9dTc6ulqtc+/I7p/Y4Opojzk+WqxBq/ j2PQj91DPjg2x+NHps7JQSA47aqmfYhoWFjjq8v8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Ricardo B. Marliere" , Mike Isely , Hans Verkuil , Mauro Carvalho Chehab , Sasha Levin , syzbot+621409285c4156a009b3@syzkaller.appspotmail.com Subject: [PATCH 6.7 254/641] media: pvrusb2: fix use after free on context disconnection Date: Mon, 22 Jan 2024 15:52:38 -0800 Message-ID: <20240122235825.861757443@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240122235818.091081209@linuxfoundation.org> References: <20240122235818.091081209@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.7-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ricardo B. Marliere [ Upstream commit ded85b0c0edd8f45fec88783d7555a5b982449c1 ] Upon module load, a kthread is created targeting the pvr2_context_thread_func function, which may call pvr2_context_destroy and thus call kfree() on the context object. However, that might happen before the usb hub_event handler is able to notify the driver. This patch adds a sanity check before the invalid read reported by syzbot, within the context disconnection call stack. Reported-and-tested-by: syzbot+621409285c4156a009b3@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/000000000000a02a4205fff8eb92@google.com/ Fixes: e5be15c63804 ("V4L/DVB (7711): pvrusb2: Fix race on module unload") Signed-off-by: Ricardo B. Marliere Acked-by: Mike Isely Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Sasha Levin --- drivers/media/usb/pvrusb2/pvrusb2-context.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/media/usb/pvrusb2/pvrusb2-context.c b/drivers/media/usb/pvrusb2/pvrusb2-context.c index 14170a5d72b3..1764674de98b 100644 --- a/drivers/media/usb/pvrusb2/pvrusb2-context.c +++ b/drivers/media/usb/pvrusb2/pvrusb2-context.c @@ -268,7 +268,8 @@ void pvr2_context_disconnect(struct pvr2_context *mp) { pvr2_hdw_disconnect(mp->hdw); mp->disconnect_flag = !0; - pvr2_context_notify(mp); + if (!pvr2_context_shutok()) + pvr2_context_notify(mp); } -- 2.43.0