From: Heiko Carstens Date: Fri, 17 Jan 2014 12:12:34 +0000 (+0100) Subject: s390/uaccess: test if current->mm is set before walking page tables X-Git-Tag: v3.14-rc1~74^2~4 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b03b467944b3e88a36a33b5429425c42dbd5b8a0;p=pandora-kernel.git s390/uaccess: test if current->mm is set before walking page tables If get_fs() == USER_DS we better test if current->mm is not zero before walking page tables. The page table walk code would try to lock mm->page_table_lock, however if mm is zero this might crash. Now it is arguably incorrect trying to access userspace if current->mm is zero, however we have seen that and s390 would be the only architecture which would crash in such a case. So we better make the page table walk code a bit more robust and report always a fault instead. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- Reading git-diff-tree failed