Messages in this thread Patch in this message | | | Date | Mon, 27 Feb 2006 14:32:03 -0800 | From | Chris Wright <> | Subject | [patch 03/39] shmdt cannot detach not-alined shm segment cleanly. |
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-stable review patch. If anyone has any objections, please let us know. ------------------
sys_shmdt() can manage shm segments which are covered by multiple vmas. (This can happen when a user uses mprotect() after shmat().)
This works well if shm is aligned to PAGE_SIZE, but if not, the last segment cannot be detached. It is because a comparison in sys_shmdt()
(vma->vm_end - addr) < size addr == return address of shmat() size == shmsize, argments to shmget()
size should be aligned to PAGE_SIZE before being compared with vma->vm_end, which is aligned.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Chris Wright <chrisw@sous-sol.org> --- ipc/shm.c | 1 + 1 file changed, 1 insertion(+)
--- linux-2.6.15.3.orig/ipc/shm.c +++ linux-2.6.15.3/ipc/shm.c @@ -863,6 +863,7 @@ asmlinkage long sys_shmdt(char __user *s * could possibly have landed at. Also cast things to loff_t to * prevent overflows and make comparisions vs. equal-width types. */ + size = PAGE_ALIGN(size); while (vma && (loff_t)(vma->vm_end - addr) <= size) { next = vma->vm_next; -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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