• Andi Kleen's avatar
    [PATCH] i386/x86-64: Fix ioremap off by one · 28019bca
    Andi Kleen authored
    From Terence Ripperda <tripperda@nvidia.com>
    
    When doing iounmap don't try to change_page_attr back the guard
    page that ioremap added.
    
    Since the last round of change_page_attr changes this would
    trigger an BUG because the reference count on the changed pages
    wouldn't match up.
    
    The problem would be only visible on machines with >3GB of memory,
    because only then the PCI memory hole is below end_pfn and
    change_page_attr is used.
    
    Fixed for both i386 and x86-64.
    
    This was actually discovered&fixed by Andrea earlier, but I goofed up
    while doing the last ioremap fixes merge and this change got lost.
    Poor Terence had to debug it again. Sorry about that.
    
    cc: andrea@suse.de
    Signed-off-by: default avatarAndi Kleen <ak@suse.de>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    28019bca
ioremap.c 7.71 KB