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 81E41145B1F; Tue, 23 Jan 2024 00:06:08 +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=1705968368; cv=none; b=fjInstLP2xUiMFb0jPJ56juKV4JNFLv8xMDAsAvrCUWJUeAqck5NExGLOc9CS5zcY8l27aEM8ICEQ3tcjwCaLPBdVQ5Y4THMKDWn/vtfsbUcyRazLMC4ApEHSTFV2Dl4dH4nqZxfgeGWhvsJtr2cPa2r+rbk0DxB64O9jbVyrAk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705968368; c=relaxed/simple; bh=ok2TpC7/ZRxb+HdfGm0NRt4ZU5YPs/NnFhd6pJiBOx0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FCiwXDdNS3BVe8pfcLSw9vVcKxwXneG89lUy1RVBaTAUaEke1TF9g6NPCf8Mk3jywC50bs14XmtiYZmciPjlztR3bHqleUsqQ7iZ1KIxH1Ns2/ufHi8y3XoBod2O3BWaGNq7xLqcKC8ikytcwIjU1fK7/G8iuJWBsTdlnEzMfhg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=vtrVxDtJ; 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="vtrVxDtJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E1E86C43390; Tue, 23 Jan 2024 00:06:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1705968368; bh=ok2TpC7/ZRxb+HdfGm0NRt4ZU5YPs/NnFhd6pJiBOx0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vtrVxDtJldP0/Ve7A3yIlEIfJV9m6yvuFAO9T0gGK/I9HXi/0N76gbYBJ7Ws0rUwq Rg8QWtYF2NhM83cGuu9lUw5YjPtjJWT/Uu9TKRqll0dHx/gGbiYfxzmv8Trup/ViL9 vMGM7N+dI6VrazBOmN2TCe2Wtx/rnxDKXYbJkoDU= 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 4.19 087/148] media: pvrusb2: fix use after free on context disconnection Date: Mon, 22 Jan 2024 15:57:23 -0800 Message-ID: <20240122235715.912033157@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240122235712.442097787@linuxfoundation.org> References: <20240122235712.442097787@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 4.19-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 d9e8481e9e28..9236463ba269 100644 --- a/drivers/media/usb/pvrusb2/pvrusb2-context.c +++ b/drivers/media/usb/pvrusb2/pvrusb2-context.c @@ -277,7 +277,8 @@ 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