From: Linus Torvalds Date: Tue, 12 Apr 2011 21:15:51 +0000 (-0700) Subject: vm: fix mlock() on stack guard page X-Git-Tag: v2.6.39-rc4~67 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=95042f9eb78a8d9a17455e2ef263f2f310ecef15;p=pandora-kernel.git vm: fix mlock() on stack guard page Commit 53a7706d5ed8 ("mlock: do not hold mmap_sem for extended periods of time") changed mlock() to care about the exact number of pages that __get_user_pages() had brought it. Before, it would only care about errors. And that doesn't work, because we also handled one page specially in __mlock_vma_pages_range(), namely the stack guard page. So when that case was handled, the number of pages that the function returned was off by one. In particular, it could be zero, and then the caller would end up not making any progress at all. Rather than try to fix up that off-by-one error for the mlock case specially, this just moves the logic to handle the stack guard page into__get_user_pages() itself, thus making all the counts come out right automatically. Reported-by: Robert Święcki Cc: Hugh Dickins Cc: Oleg Nesterov Cc: stable@kernel.org Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed