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 33D4D1EC4DE; Sat, 21 Dec 2024 09:43:56 +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=1734774237; cv=none; b=Q4KvX2qqAV1+MGxHaDl7LycSNhp7+knBe9D+Dq6snph8mR5irb5XcuhDgY3N4MLzm7lny2z/6ZfkoZ9WBb5c5eIBDjzxzTAJwnxHBYESW7fM8lg4Nxu7JJEIKF7ZQW81ePvs2c1M7CPBpa3ysdsX7ePSLqK3pkKd9ZbMCLpBQZk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734774237; c=relaxed/simple; bh=1j7vMhlitSCs0D8VhiyVnhL6zabLFb/87788qyb++AI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=J2I1J6PrP5qIvQ8THKEFY53maJ/myws0dqKIEbl3R0wd8JZLjuoZluxUPgGW460lILjUJFIk6NZgcKZw1Wn72KSpCzfI4vwgoO041RHcV8Ta+xMpRkhHIxmjaULu3hr6ZV0YGTKEv/jlNIEHJCFgRVWNc6Gpo4XjCCpHp+NTEtY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=T4vX+0AX; 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="T4vX+0AX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5A4E0C4CED6; Sat, 21 Dec 2024 09:43:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1734774236; bh=1j7vMhlitSCs0D8VhiyVnhL6zabLFb/87788qyb++AI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=T4vX+0AXCxNOsl2AZe9+kv47LCLVcOfFTadmoaqvPygOXd+PNoNcYUGH9AxmLpqoh KFMdc232kx5PkjmnRltpfVsuM3cqIxFB6R5V1u7jsvugxnl0mdTPk6t5hWMuLagsAW jbRqlVM08Pwds9KnEWgiprbCfo5/nHHT16r4+hqc= Date: Sat, 21 Dec 2024 10:43:14 +0100 From: Greg KH To: Nihar Chaithanya Cc: dpenkler@gmail.com, dan.carpenter@linaro.org, roheetchavan@gmail.com, arnd@arndb.de, linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org, skhan@linuxfoundation.org Subject: Re: [PATCH v2] staging: gpib: cb7210: Add error handling Message-ID: <2024122133-outskirts-causing-099a@gregkh> References: <20241221091121.35476-1-niharchaithanya@gmail.com> <2024122119-unclamped-affecting-0e0a@gregkh> Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2024122119-unclamped-affecting-0e0a@gregkh> On Sat, Dec 21, 2024 at 10:25:41AM +0100, Greg KH wrote: > On Sat, Dec 21, 2024 at 02:41:25PM +0530, Nihar Chaithanya wrote: > > The if condition in cb7210_init_module() would always fail as > > the value of err is constantly 0. The function > > cb_pcmcia_init_module() can be refactored into a single line, > > and can be replaced entirely with pcmcia_register_driver(). > > > > Replace redundant cb_pcmcia_init_module() with > > pcmcia_register_driver() which returns appropriate error code if > > it fails. Handle the error if it fails and print the debug message. > > > > This issue was reported by Coverity Scan. > > Report: > > CID 1635894: (#1 of 1): 'Constant' variable guards dead code (DEADCODE) > > dead_error_line: Execution cannot reach this statement: return -1;. > > > > Signed-off-by: Nihar Chaithanya > > --- > > v1 --> v2: Replaced the redundant cb_pcmcia_init_module() with > > pcmcia_register_driver(). > > > > drivers/staging/gpib/cb7210/cb7210.c | 13 ++++--------- > > 1 file changed, 4 insertions(+), 9 deletions(-) > > > > diff --git a/drivers/staging/gpib/cb7210/cb7210.c b/drivers/staging/gpib/cb7210/cb7210.c > > index 63df7f3eb3f3..abd6632d8448 100644 > > --- a/drivers/staging/gpib/cb7210/cb7210.c > > +++ b/drivers/staging/gpib/cb7210/cb7210.c > > @@ -1351,12 +1351,6 @@ static struct pcmcia_driver cb_gpib_cs_driver = { > > .resume = cb_gpib_resume, > > }; > > > > -int cb_pcmcia_init_module(void) > > -{ > > - pcmcia_register_driver(&cb_gpib_cs_driver); > > - return 0; > > -} > > - > > void cb_pcmcia_cleanup_module(void) > > { > > DEBUG(0, "cb_gpib_cs: unloading\n"); > > @@ -1526,11 +1520,12 @@ static int __init cb7210_init_module(void) > > gpib_register_driver(&cb_pcmcia_interface, THIS_MODULE); > > gpib_register_driver(&cb_pcmcia_accel_interface, THIS_MODULE); > > gpib_register_driver(&cb_pcmcia_unaccel_interface, THIS_MODULE); > > - err += cb_pcmcia_init_module(); > > + err = pcmcia_register_driver(&cb_gpib_cs_driver); > > #endif > > - if (err) > > + if (err) { > > + pr_err("cb7210: registering PCMCIA driver with the bus core failed\n"); > > return -1; > > Not your issue, but "-1" is not a valid error number, shouldn't this be > returning a real error (i.e. the one that was returned?) > > And err += is crazy, thanks for removing that, BUT you forgot to unwind > the previous functions so now if pcmcia_register_driver() fails, you > have a semi-registered system and then the module will unload (as init > fails) and bad things will happen :( > > So you kind of just made the code worse overall, not better, which > really isn't a good idea for a "bugfix" that covertity was trying to > point out. And (this is taking you down a path that is much larger than you expected to just fix this one issue, sorry), it looks like gpib_register_driver() can fail, so it MUST return an error value so you can properly unwind from it. So that too needs to be fixed up here (also minor nit, gpib_register_driver() should not be calling pr_info(), but that's a different issue.) In all, there are loads of tiny things like this to fix up in the gpib code, which is great, have fun! thanks, greg k-h