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 291F312C52C; Tue, 23 Jan 2024 00:15:36 +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=1705968937; cv=none; b=NOSkX86Caz2SYpPfbiRPmQ5HUKa4Ke6jn8ZdRzqzP7gmn7GO0656KHTgsrlIVSYFsv2a7l4WjBn4Jo8UdIx0cgS9GEfB2YBxcp2ckyNdCy+DsoLwhkTOIupYuV6If2f/YBEx6fCFtXfxWPeJ7kseBrD+d4ysKogGkd4beGzeskI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705968937; c=relaxed/simple; bh=AdvQvEoFsEe9+8WmQ6K84hdHcgRplZmuq5RUjTayJOQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QiBwgcoiipgJ61JAZC/lfcupN8z00ato3cwx1MNH6wpGrc03iLImD0zmvbO5Xp4W073R4DNPLrRFP2/goGbcFeAi2hNVcax1yPWH3NUm9HmqkPSnOjViVeDTCXD2TZW5JGu4GlNeBtpnC1tYR8IPAfkMVMw2L5q9viAtdD5AIrA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hZ33vsUQ; 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="hZ33vsUQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 70DBFC43390; Tue, 23 Jan 2024 00:15:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1705968936; bh=AdvQvEoFsEe9+8WmQ6K84hdHcgRplZmuq5RUjTayJOQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hZ33vsUQcbqsrNsgUrFUHOUcRrFsGLvZ4F3yIZSh6lmadI1PdNIhqiUOq8lRwa41R 8UOUCViJsVRxvhj1K+m6uFjUiVAVnNuPg0F8ImTRsW4PHnNL8pGP4nRqeKBHC1bRLR kblnSH5OfKjbPbKUIqcXtgFDwRVjXa6tpzISrkP4= 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 5.4 110/194] media: pvrusb2: fix use after free on context disconnection Date: Mon, 22 Jan 2024 15:57:20 -0800 Message-ID: <20240122235723.950780333@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240122235719.206965081@linuxfoundation.org> References: <20240122235719.206965081@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-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