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 9E383569D for ; Sun, 28 May 2023 19:32:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2C25CC433EF; Sun, 28 May 2023 19:32:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1685302328; bh=+JYt3p0XP3EDMuzLeobbsdevTRb4nvQByz4E98TxOmQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NthsyIntRxYFzgsuPoab2QRWy2lr1fpZzF3YQVWbFkjmioaxmFA8bvg4k16/2oRof WqACMwBbmj4AxX6ysRgJSooOUD05jJJVja+ez7dI+R8AG1SBFQo3y0yyYwdIcrQe1O kA1e6V0aTWR0UVu/L56kRd3BZzIrOEl/7LoDfHxo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sudeep Holla Subject: [PATCH 6.3 090/127] firmware: arm_ffa: Check if ffa_driver remove is present before executing Date: Sun, 28 May 2023 20:11:06 +0100 Message-Id: <20230528190839.254922581@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230528190836.161231414@linuxfoundation.org> References: <20230528190836.161231414@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Sudeep Holla commit b71b55248a580e9c9befc4ae060539f1f8e477da upstream. Currently ffa_drv->remove() is called unconditionally from ffa_device_remove(). Since the driver registration doesn't check for it and allows it to be registered without .remove callback, we need to check for the presence of it before executing it from ffa_device_remove() to above a NULL pointer dereference like the one below: | Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 | Mem abort info: | ESR = 0x0000000086000004 | EC = 0x21: IABT (current EL), IL = 32 bits | SET = 0, FnV = 0 | EA = 0, S1PTW = 0 | FSC = 0x04: level 0 translation fault | user pgtable: 4k pages, 48-bit VAs, pgdp=0000000881cc8000 | [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 | Internal error: Oops: 0000000086000004 [#1] PREEMPT SMP | CPU: 3 PID: 130 Comm: rmmod Not tainted 6.3.0-rc7 #6 | Hardware name: FVP Base RevC (DT) | pstate: 63402809 (nZCv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=-c) | pc : 0x0 | lr : ffa_device_remove+0x20/0x2c | Call trace: | 0x0 | device_release_driver_internal+0x16c/0x260 | driver_detach+0x90/0xd0 | bus_remove_driver+0xdc/0x11c | driver_unregister+0x30/0x54 | ffa_driver_unregister+0x14/0x20 | cleanup_module+0x18/0xeec | __arm64_sys_delete_module+0x234/0x378 | invoke_syscall+0x40/0x108 | el0_svc_common+0xb4/0xf0 | do_el0_svc+0x30/0xa4 | el0_svc+0x2c/0x7c | el0t_64_sync_handler+0x84/0xf0 | el0t_64_sync+0x190/0x194 Fixes: 244f5d597e1e ("firmware: arm_ffa: Add missing remove callback to ffa_bus_type") Link: https://lore.kernel.org/r/20230419-ffa_fixes_6-4-v2-1-d9108e43a176@arm.com Signed-off-by: Sudeep Holla Signed-off-by: Greg Kroah-Hartman --- drivers/firmware/arm_ffa/bus.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/firmware/arm_ffa/bus.c +++ b/drivers/firmware/arm_ffa/bus.c @@ -53,7 +53,8 @@ static void ffa_device_remove(struct dev { struct ffa_driver *ffa_drv = to_ffa_driver(dev->driver); - ffa_drv->remove(to_ffa_dev(dev)); + if (ffa_drv->remove) + ffa_drv->remove(to_ffa_dev(dev)); } static int ffa_device_uevent(const struct device *dev, struct kobj_uevent_env *env)