From: Al Viro Date: Wed, 7 Mar 2012 05:16:35 +0000 (+0000) Subject: aio: fix io_setup/io_destroy race X-Git-Tag: v3.2.12~39 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=00a1b4bfdec249286c6ed902773dd8699ae070d7;p=pandora-kernel.git aio: fix io_setup/io_destroy race commit 86b62a2cb4fc09037bbce2959d2992962396fd7f upstream. Have ioctx_alloc() return an extra reference, so that caller would drop it on success and not bother with re-grabbing it on failure exit. The current code is obviously broken - io_destroy() from another thread that managed to guess the address io_setup() would've returned would free ioctx right under us; gets especially interesting if aio_context_t * we pass to io_setup() points to PROT_READ mapping, so put_user() fails and we end up doing io_destroy() on kioctx another thread has just got freed... Signed-off-by: Al Viro Acked-by: Benjamin LaHaise Reviewed-by: Jeff Moyer Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- Reading git-diff-tree failed