4.17-stable review patch. If anyone has any objections, please let me know.
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From: Michael Schmitz schmitzmic@gmail.com
commit 3f90f9ef2dda316d64e420d5d51ba369587ccc55 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/m68k/mm/kmap.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/m68k/mm/kmap.c +++ b/arch/m68k/mm/kmap.c @@ -89,7 +89,8 @@ static inline void free_io_area(void *ad 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; }