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@xxxxxxxxx>
[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@xxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
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;
}
--
2.17.1
