From: Dan Carpenter <dan.carpenter@oracle.com>
To: Wolfram Sang <wsa@the-dreams.de>
Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
Erico Nunes <erico.nunes@datacom.ind.br>,
kernel-janitors@vger.kernel.org, LKP <lkp@01.org>
Subject: Re: [PATCH] Revert "i2c: dev: switch from register_chrdev to cdev API"
Date: Mon, 30 May 2016 07:05:47 +0000 [thread overview]
Message-ID: <20160530070547.GA18199@mwanda> (raw)
In-Reply-To: <20160528160458.GA1614@katana>
On Sat, May 28, 2016 at 06:04:58PM +0200, Wolfram Sang wrote:
>
> > These kinds of use after frees don't always cause a runtime problem. I
> > found it using static analysis, but I bet you could detect it if you
> > enabled kasan. The other option is to enable PAGE_POISONING?
>
> Thanks, PAGE_POISONING did trigger the issue. So, I now picked up your
> patch instead of the revert because I could verify the problem and the
> proper solution. Thanks again.
>
> What I still wonder: Which analysis reported the problem to you? I
> always run sparse, smatch, cppcheck, and coccicheck on the patches when
> applying and no-one reported the issue.
It's a Smatch warning but you have to build the cross function db to
detect this. It takes a while (a few hours) but the command is simple
enough.
./smatch_scripts/build_kernel_data.sh
regards,
dan carpenter
WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <dan.carpenter@oracle.com>
To: Wolfram Sang <wsa@the-dreams.de>
Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
Erico Nunes <erico.nunes@datacom.ind.br>,
kernel-janitors@vger.kernel.org, LKP <lkp@01.org>
Subject: Re: [PATCH] Revert "i2c: dev: switch from register_chrdev to cdev API"
Date: Mon, 30 May 2016 10:05:47 +0300 [thread overview]
Message-ID: <20160530070547.GA18199@mwanda> (raw)
In-Reply-To: <20160528160458.GA1614@katana>
On Sat, May 28, 2016 at 06:04:58PM +0200, Wolfram Sang wrote:
>
> > These kinds of use after frees don't always cause a runtime problem. I
> > found it using static analysis, but I bet you could detect it if you
> > enabled kasan. The other option is to enable PAGE_POISONING?
>
> Thanks, PAGE_POISONING did trigger the issue. So, I now picked up your
> patch instead of the revert because I could verify the problem and the
> proper solution. Thanks again.
>
> What I still wonder: Which analysis reported the problem to you? I
> always run sparse, smatch, cppcheck, and coccicheck on the patches when
> applying and no-one reported the issue.
It's a Smatch warning but you have to build the cross function db to
detect this. It takes a while (a few hours) but the command is simple
enough.
./smatch_scripts/build_kernel_data.sh
regards,
dan carpenter
WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <dan.carpenter@oracle.com>
To: lkp@lists.01.org
Subject: Re: [PATCH] Revert "i2c: dev: switch from register_chrdev to cdev API"
Date: Mon, 30 May 2016 10:05:47 +0300 [thread overview]
Message-ID: <20160530070547.GA18199@mwanda> (raw)
In-Reply-To: <20160528160458.GA1614@katana>
[-- Attachment #1: Type: text/plain, Size: 887 bytes --]
On Sat, May 28, 2016 at 06:04:58PM +0200, Wolfram Sang wrote:
>
> > These kinds of use after frees don't always cause a runtime problem. I
> > found it using static analysis, but I bet you could detect it if you
> > enabled kasan. The other option is to enable PAGE_POISONING?
>
> Thanks, PAGE_POISONING did trigger the issue. So, I now picked up your
> patch instead of the revert because I could verify the problem and the
> proper solution. Thanks again.
>
> What I still wonder: Which analysis reported the problem to you? I
> always run sparse, smatch, cppcheck, and coccicheck on the patches when
> applying and no-one reported the issue.
It's a Smatch warning but you have to build the cross function db to
detect this. It takes a while (a few hours) but the command is simple
enough.
./smatch_scripts/build_kernel_data.sh
regards,
dan carpenter
next prev parent reply other threads:[~2016-05-30 7:05 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-28 9:07 [PATCH] Revert "i2c: dev: switch from register_chrdev to cdev API" Wolfram Sang
2016-05-28 9:07 ` Wolfram Sang
2016-05-28 9:07 ` Wolfram Sang
2016-05-28 9:15 ` Dan Carpenter
2016-05-28 9:15 ` Dan Carpenter
2016-05-28 9:15 ` Dan Carpenter
2016-05-28 16:04 ` Wolfram Sang
2016-05-28 16:04 ` Wolfram Sang
2016-05-28 16:04 ` Wolfram Sang
2016-05-30 7:05 ` Dan Carpenter [this message]
2016-05-30 7:05 ` Dan Carpenter
2016-05-30 7:05 ` Dan Carpenter
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