From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Date: Sat, 28 May 2016 16:04:58 +0000 Subject: Re: [PATCH] Revert "i2c: dev: switch from register_chrdev to cdev API" Message-Id: <20160528160458.GA1614@katana> MIME-Version: 1 Content-Type: multipart/mixed; boundary="T4sUOijqQbZv57TR" List-Id: References: <1464426467-1824-1-git-send-email-wsa@the-dreams.de> <20160528091559.GR11011@mwanda> In-Reply-To: <20160528091559.GR11011@mwanda> To: Dan Carpenter Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, Erico Nunes , kernel-janitors@vger.kernel.org, LKP --T4sUOijqQbZv57TR Content-Type: text/plain; charset=us-ascii Content-Disposition: inline > 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. Wolfram --T4sUOijqQbZv57TR Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJXScGpAAoJEBQN5MwUoCm2On0P/AkADGBmG/2uWkVvY+fPag4i Lc9si0cBxJFN0OucrJ/QAbEPGU7zX8s8jR/pePWCBg976IdJ3mLj2C7T+RQXXEGO pSxkJS0EGmjNZC/e6hUOxnng+KZC0HM7vC+o5Qi1JVbS8ClJM8bZEvtvSHVIfGea HZG713CdhQfiD6tRyDjS9jx/oAs+0yZ6z/40q9YzvEP6lKdYj1EZQ4srRS9Yqe2C SAi3i29q48pS1gBCm+NKTXylXrozCPAbouWF7ydxpgiZ4UlSqEgmnAhABG8dAmkV 6aRvt4qXL+pKAmSneg+rKA1YEuZS/dZwY/vr6SL/Hclu7nsxd0PdZxDlPOSQWq6i ktY62TvGsM9eXpuaCX35xYIjSW5o4Q0a3uj7NxvHLiMBK7Nq37hP6+XHH3wVEDdf LJO6fPvrCqGVU8NU4Ru7m4beDLhIt60OAj/2MMPxfe1eQAVWQFezMeXglDuR3g6D SxMiwuj+0rayocTP/r23mpRAURuiRDRDuWxFvOHXNPpAzkzuo5ymiM+kSlzuceT6 B/AF+mu8i+H34ZCYu4LF07gxcOhTc9ykCxvMhSN75KvYZ0RL4ULRSMwicLOkuV0k EIBT3jVptNHKhqGtom8tpjcC+mAdCyqcSjnxkfsMv3cLpWWOBdFAvc3DfnFy6670 DVG5Kdeu3rx192uKdkw3 =DLQd -----END PGP SIGNATURE----- --T4sUOijqQbZv57TR-- From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: Re: [PATCH] Revert "i2c: dev: switch from register_chrdev to cdev API" Date: Sat, 28 May 2016 18:04:58 +0200 Message-ID: <20160528160458.GA1614@katana> References: <1464426467-1824-1-git-send-email-wsa@the-dreams.de> <20160528091559.GR11011@mwanda> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="T4sUOijqQbZv57TR" Return-path: Content-Disposition: inline In-Reply-To: <20160528091559.GR11011@mwanda> Sender: linux-kernel-owner@vger.kernel.org To: Dan Carpenter Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, Erico Nunes , kernel-janitors@vger.kernel.org, LKP List-Id: linux-i2c@vger.kernel.org --T4sUOijqQbZv57TR Content-Type: text/plain; charset=us-ascii Content-Disposition: inline > 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. Wolfram --T4sUOijqQbZv57TR Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJXScGpAAoJEBQN5MwUoCm2On0P/AkADGBmG/2uWkVvY+fPag4i Lc9si0cBxJFN0OucrJ/QAbEPGU7zX8s8jR/pePWCBg976IdJ3mLj2C7T+RQXXEGO pSxkJS0EGmjNZC/e6hUOxnng+KZC0HM7vC+o5Qi1JVbS8ClJM8bZEvtvSHVIfGea HZG713CdhQfiD6tRyDjS9jx/oAs+0yZ6z/40q9YzvEP6lKdYj1EZQ4srRS9Yqe2C SAi3i29q48pS1gBCm+NKTXylXrozCPAbouWF7ydxpgiZ4UlSqEgmnAhABG8dAmkV 6aRvt4qXL+pKAmSneg+rKA1YEuZS/dZwY/vr6SL/Hclu7nsxd0PdZxDlPOSQWq6i ktY62TvGsM9eXpuaCX35xYIjSW5o4Q0a3uj7NxvHLiMBK7Nq37hP6+XHH3wVEDdf LJO6fPvrCqGVU8NU4Ru7m4beDLhIt60OAj/2MMPxfe1eQAVWQFezMeXglDuR3g6D SxMiwuj+0rayocTP/r23mpRAURuiRDRDuWxFvOHXNPpAzkzuo5ymiM+kSlzuceT6 B/AF+mu8i+H34ZCYu4LF07gxcOhTc9ykCxvMhSN75KvYZ0RL4ULRSMwicLOkuV0k EIBT3jVptNHKhqGtom8tpjcC+mAdCyqcSjnxkfsMv3cLpWWOBdFAvc3DfnFy6670 DVG5Kdeu3rx192uKdkw3 =DLQd -----END PGP SIGNATURE----- --T4sUOijqQbZv57TR-- From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============1132945157854162471==" MIME-Version: 1.0 From: Wolfram Sang To: lkp@lists.01.org Subject: Re: [PATCH] Revert "i2c: dev: switch from register_chrdev to cdev API" Date: Sat, 28 May 2016 18:04:58 +0200 Message-ID: <20160528160458.GA1614@katana> In-Reply-To: <20160528091559.GR11011@mwanda> List-Id: --===============1132945157854162471== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable > 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. 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