Commit fdea03e1 authored by Alexander Potapenko's avatar Alexander Potapenko Committed by Andrew Morton

mm: kmsan: handle alloc failures in kmsan_ioremap_page_range()

Similarly to kmsan_vmap_pages_range_noflush(), kmsan_ioremap_page_range()
must also properly handle allocation/mapping failures.  In the case of
such, it must clean up the already created metadata mappings and return an
error code, so that the error can be propagated to ioremap_page_range(). 
Without doing so, KMSAN may silently fail to bring the metadata for the
page range into a consistent state, which will result in user-visible
crashes when trying to access them.

Link: https://lkml.kernel.org/r/20230413131223.4135168-2-glider@google.com
Fixes: b073d7f8 ("mm: kmsan: maintain KMSAN metadata for page operations")
Signed-off-by: default avatarAlexander Potapenko <glider@google.com>
Reported-by: default avatarDipanjan Das <mail.dipanjan.das@gmail.com>
  Link: https://lore.kernel.org/linux-mm/CANX2M5ZRrRA64k0hOif02TjmY9kbbO2aCBPyq79es34RXZ=cAw@mail.gmail.com/Reviewed-by: default avatarMarco Elver <elver@google.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 47ebd031
......@@ -160,9 +160,10 @@ void kmsan_vunmap_range_noflush(unsigned long start, unsigned long end);
* @page_shift: page_shift argument passed to vmap_range_noflush().
*
* KMSAN creates new metadata pages for the physical pages mapped into the
* virtual memory.
* virtual memory. Returns 0 on success, callers must check for non-zero return
* value.
*/
void kmsan_ioremap_page_range(unsigned long addr, unsigned long end,
int kmsan_ioremap_page_range(unsigned long addr, unsigned long end,
phys_addr_t phys_addr, pgprot_t prot,
unsigned int page_shift);
......@@ -296,12 +297,12 @@ static inline void kmsan_vunmap_range_noflush(unsigned long start,
{
}
static inline void kmsan_ioremap_page_range(unsigned long start,
static inline int kmsan_ioremap_page_range(unsigned long start,
unsigned long end,
phys_addr_t phys_addr,
pgprot_t prot,
phys_addr_t phys_addr, pgprot_t prot,
unsigned int page_shift)
{
return 0;
}
static inline void kmsan_iounmap_page_range(unsigned long start,
......
......@@ -148,35 +148,74 @@ void kmsan_vunmap_range_noflush(unsigned long start, unsigned long end)
* into the virtual memory. If those physical pages already had shadow/origin,
* those are ignored.
*/
void kmsan_ioremap_page_range(unsigned long start, unsigned long end,
int kmsan_ioremap_page_range(unsigned long start, unsigned long end,
phys_addr_t phys_addr, pgprot_t prot,
unsigned int page_shift)
{
gfp_t gfp_mask = GFP_KERNEL | __GFP_ZERO;
struct page *shadow, *origin;
unsigned long off = 0;
int nr;
int nr, err = 0, clean = 0, mapped;
if (!kmsan_enabled || kmsan_in_runtime())
return;
return 0;
nr = (end - start) / PAGE_SIZE;
kmsan_enter_runtime();
for (int i = 0; i < nr; i++, off += PAGE_SIZE) {
for (int i = 0; i < nr; i++, off += PAGE_SIZE, clean = i) {
shadow = alloc_pages(gfp_mask, 1);
origin = alloc_pages(gfp_mask, 1);
__vmap_pages_range_noflush(
if (!shadow || !origin) {
err = -ENOMEM;
goto ret;
}
mapped = __vmap_pages_range_noflush(
vmalloc_shadow(start + off),
vmalloc_shadow(start + off + PAGE_SIZE), prot, &shadow,
PAGE_SHIFT);
__vmap_pages_range_noflush(
if (mapped) {
err = mapped;
goto ret;
}
shadow = NULL;
mapped = __vmap_pages_range_noflush(
vmalloc_origin(start + off),
vmalloc_origin(start + off + PAGE_SIZE), prot, &origin,
PAGE_SHIFT);
if (mapped) {
__vunmap_range_noflush(
vmalloc_shadow(start + off),
vmalloc_shadow(start + off + PAGE_SIZE));
err = mapped;
goto ret;
}
origin = NULL;
}
/* Page mapping loop finished normally, nothing to clean up. */
clean = 0;
ret:
if (clean > 0) {
/*
* Something went wrong. Clean up shadow/origin pages allocated
* on the last loop iteration, then delete mappings created
* during the previous iterations.
*/
if (shadow)
__free_pages(shadow, 1);
if (origin)
__free_pages(origin, 1);
__vunmap_range_noflush(
vmalloc_shadow(start),
vmalloc_shadow(start + clean * PAGE_SIZE));
__vunmap_range_noflush(
vmalloc_origin(start),
vmalloc_origin(start + clean * PAGE_SIZE));
}
flush_cache_vmap(vmalloc_shadow(start), vmalloc_shadow(end));
flush_cache_vmap(vmalloc_origin(start), vmalloc_origin(end));
kmsan_leave_runtime();
return err;
}
void kmsan_iounmap_page_range(unsigned long start, unsigned long end)
......
......@@ -313,7 +313,7 @@ int ioremap_page_range(unsigned long addr, unsigned long end,
ioremap_max_page_shift);
flush_cache_vmap(addr, end);
if (!err)
kmsan_ioremap_page_range(addr, end, phys_addr, prot,
err = kmsan_ioremap_page_range(addr, end, phys_addr, prot,
ioremap_max_page_shift);
return err;
}
......
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