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Original file line number | Diff line number | Diff line change |
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@@ -0,0 +1,43 @@ | ||
On Fri, Jan 03, 2025 at 02:00:44PM +0100, Borislav Petkov wrote: | ||
> Adding the author in Fixes to Cc | ||
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Thanks, Boris! | ||
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> On Fri, Jan 03, 2025 at 07:56:31AM +0100, Juergen Gross wrote: | ||
> > The recently introduced ROX cache for modules is assuming large page | ||
> > support in 64-bit mode without testing the related feature bit. This | ||
> > results in breakage when running as a Xen PV guest, as in this mode | ||
> > large pages are not supported. | ||
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The ROX cache does not assume support for large pages, it just had a bug | ||
when dealing with base pages and the patch below should fix it. | ||
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Restricting ROX cache only for configurations that support large pages | ||
makes sense on it's own because there's no real benefit from the cache on | ||
such systems, but it does not fix the issue but rather covers it up. | ||
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diff --git a/mm/execmem.c b/mm/execmem.c | ||
index be6b234c032e..0090a6f422aa 100644 | ||
--- a/mm/execmem.c | ||
+++ b/mm/execmem.c | ||
@@ -266,6 +266,7 @@ static int execmem_cache_populate(struct execmem_range *range, size_t size) | ||
{ | ||
unsigned long vm_flags = VM_ALLOW_HUGE_VMAP; | ||
unsigned long start, end; | ||
+ unsigned int page_shift; | ||
struct vm_struct *vm; | ||
size_t alloc_size; | ||
int err = -ENOMEM; | ||
@@ -296,8 +297,9 @@ static int execmem_cache_populate(struct execmem_range *range, size_t size) | ||
if (err) | ||
goto err_free_mem; | ||
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+ page_shift = get_vm_area_page_order(vm) + PAGE_SHIFT; | ||
err = vmap_pages_range_noflush(start, end, range->pgprot, vm->pages, | ||
- PMD_SHIFT); | ||
+ page_shift); | ||
if (err) | ||
goto err_free_mem; | ||
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-- | ||
2.45.2 |