Commit f912696a authored Nov 06, 2005 by Bart Oldeman Committed by Linus Torvalds Nov 05, 2005

[PATCH] reset tss->io_bitmap_owner in sys_ioperm()



my patch "x86: initialise tss->io_bitmap_owner to something" (commit ID
d5cd4aad) introduced a problem with a
program (DOSEMU) that called ioperm after already doing some port i/o.

The problem is that a process switch return causes tss->io_bitmap_base
to be set to IO_BITMAP_OFFSET so that the fault (that *really* sets the
io bitmap) never triggers.

This fixes that regression.

Signed-off-by: Bart Oldeman <bartoldeman@users.sourceforge.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent 88dcb6c4

arch/i386/kernel/ioport.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -108,8 +108,11 @@ asmlinkage long sys_ioperm(unsigned long from, unsigned long num, int turn_on)
		/*
		* Sets the lazy trigger so that the next I/O operation will
		* reload the correct bitmap.
		* Reset the owner so that a process switch will not set
		* tss->io_bitmap_base to IO_BITMAP_OFFSET.
		*/
		tss->io_bitmap_base = INVALID_IO_BITMAP_OFFSET_LAZY;
		tss->io_bitmap_owner = NULL;

		put_cpu();