From: Hugh Dickins Date: Sun, 14 Jun 2015 16:48:09 +0000 (-0700) Subject: mm: shmem_zero_setup skip security check and lockdep conflict with XFS X-Git-Tag: omap-for-v4.2/fixes-rc1^2~196 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=66fc13039422ba7df2d01a8ee0873e4ef965b50b;p=pandora-kernel.git mm: shmem_zero_setup skip security check and lockdep conflict with XFS It appears that, at some point last year, XFS made directory handling changes which bring it into lockdep conflict with shmem_zero_setup(): it is surprising that mmap() can clone an inode while holding mmap_sem, but that has been so for many years. Since those few lockdep traces that I've seen all implicated selinux, I'm hoping that we can use the __shmem_file_setup(,,,S_PRIVATE) which v3.13's commit c7277090927a ("security: shmem: implement kernel private shmem inodes") introduced to avoid LSM checks on kernel-internal inodes: the mmap("/dev/zero") cloned inode is indeed a kernel-internal detail. This also covers the !CONFIG_SHMEM use of ramfs to support /dev/zero (and MAP_SHARED|MAP_ANONYMOUS). I thought there were also drivers which cloned inode in mmap(), but if so, I cannot locate them now. Reported-and-tested-by: Prarit Bhargava Reported-and-tested-by: Daniel Wagner Reported-and-tested-by: Morten Stevens Signed-off-by: Hugh Dickins Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed