If 020/030 support is enabled, get_io_area() leaves an IO_SIZE gap between mappings which is added to the vm_struct representing the mapping. __ioremap() uses the actual requested size (after alignment), while __iounmap() is passed the size from the vm_struct.

On 020/030, early termination descriptors are used to set up mappings of extent 'size', which are validated on unmapping. The unmapped gap of size IO_SIZE defeats the sanity check of the pmd tables, causing __iounmap() to loop forever on 030.

On 040/060, unmapping of page table entries does not check for a valid mapping, so the umapping loop always completes there.

Adjust size to be unmapped by the gap that had been added in the vm_struct prior.

This fixes the hang in atari_platform_init() reported a long time ago, and a similar one reported by Finn recently (addressed by removing ioremap() use from the SWIM driver.

Tested on my Falcon in 030 mode - untested but should work the same on 040/060 (the extra page tables cleared there would never have been set up anyway).

Signed-off-by: Michael Schmitz schmitzmic@gmail.com [geert: Minor commit description improvements] [geert: This was fixed in 2.4.23, but not in 2.5.x] Signed-off-by: Geert Uytterhoeven geert@linux-m68k.org Cc: stable@vger.kernel.org --- arch/m68k/mm/kmap.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/m68k/mm/kmap.c b/arch/m68k/mm/kmap.c index 6e4955bc542b..fcd52cefee29 100644 --- a/arch/m68k/mm/kmap.c +++ b/arch/m68k/mm/kmap.c @@ -88,7 +88,8 @@ static inline void free_io_area(void *addr) for (p = &iolist ; (tmp = *p) ; p = &tmp->next) { if (tmp->addr == addr) { *p = tmp->next; - __iounmap(tmp->addr, tmp->size); + /* remove gap added in get_io_area() */ + __iounmap(tmp->addr, tmp->size - IO_SIZE); kfree(tmp); return; }