From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomi Valkeinen Date: Wed, 30 Oct 2013 11:20:37 +0000 Subject: Re: [RFC PATCH RESEND] fb: reorder the lock sequence to fix a potential lockdep Message-Id: <5270EB85.1030103@ti.com> MIME-Version: 1 Content-Type: multipart/mixed; boundary="dfiQb3TWVNumgxRMhjITDr4I4crUv1apa" List-Id: References: <526DFDA8.7010806@cn.fujitsu.com> In-Reply-To: <526DFDA8.7010806@cn.fujitsu.com> To: Gu Zheng , Jean-Christophe PLAGNIOL-VILLARD Cc: Linux Fbdev development list , linux-kernel --dfiQb3TWVNumgxRMhjITDr4I4crUv1apa Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Hi, On 2013-10-28 08:01, Gu Zheng wrote: > Following commits: > 50e244cc79 fb: rework locking to fix lock ordering on takeover > e93a9a8687 fb: Yet another band-aid for fixing lockdep mess > 054430e773 fbcon: fix locking harder >=20 > reworked locking to fix related lock ordering on takeover, and introduc= ed console_lock > into fbmem, but it seems that the new lock sequence(fb_info->lock ---> = console_lock) > is against with the one in console_callback(console_lock ---> fb_info->= lock), and leads to > a potential deadlock as following: A quick grep shows that there are other places than fbmem.c which use lock_fb_info and console_lock, for example drivers/video/sh_mobile_lcdcfb= =2Ec. Tomi --dfiQb3TWVNumgxRMhjITDr4I4crUv1apa Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.14 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBAgAGBQJScOuFAAoJEPo9qoy8lh71nTMP/0LXtkpHctkUogDJZHlE14Gf 8xMRFtHFauyf950HUCro4VJ+vf3PaLQXK5LPJAzY8VnCkQUBZGEGiOrh7u13tK4O nocFMebEp6EJ5NVQwEb5SzTwpi6eNB7drhsJYHegM6Yi/tzMS/KnmL0OUGVAlKTq fUG1wIxam0ZzCDUsgi6FJZGS/6oCXi7rF6RAbZKf52P1X8Ea59bGahtuA+86PCla m9j0TnNTPfsvSTT2FkytxVMapa3spb+2aJOrX5+E73dW8MqdcIJIxDXJ0GJwbVwI y2CQjmOM2vJRkGuCZDlUbrI3w8Pw8N8qCRpaSawdVtckdkrXYPLUVkQmVLEMgux+ ioTSedlNdyisvr+ql2SONIfPtliRKOR2tw87udDhKM/SeCoUDCik95Nr+OEVPL/p 7NOw6AAfesKqkROFjRnEA+TJ3B8BnB5YfNr2lNwsKFJNASiUjjrXXuyXX1AfglnK DToaM9ys+hmYqOvTf8aFEuvZc79mQ17Tj+nCPvZIzuTfyltofyy5FWEc0EnYEK9M 4VbYWShHrlQh5hXFxbaL7DN5wViuROxgOZFYN2ZAMdAWOiIf5G/aajk3LsPpK5CK m5+ygae6Hy+ELAP5+VXoQfpc3lnPfB2N72fHNFCVBapwVKKwut3H5PGKwdNLgBLJ qz5/W8fQFaVxYG/mf3iR =XuwQ -----END PGP SIGNATURE----- --dfiQb3TWVNumgxRMhjITDr4I4crUv1apa--