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mm: kmsan: handle alloc failures in kmsan_vmap_pages_range_noflush()

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As reported by Dipanjan Das, when KMSAN is used together with kernel fault
injection (or, generally, even without the latter), calls to kcalloc() or
__vmap_pages_range_noflush() may fail, leaving the metadata mappings for
the virtual mapping in an inconsistent state.  When these metadata
mappings are accessed later, the kernel crashes.

To address the problem, we return a non-zero error code from
kmsan_vmap_pages_range_noflush() in the case of any allocation/mapping
failure inside it, and make vmap_pages_range_noflush() return an error if
KMSAN fails to allocate the metadata.

This patch also removes KMSAN_WARN_ON() from vmap_pages_range_noflush(),
as these allocation failures are not fatal anymore.

Link: https://lkml.kernel.org/r/20230413131223.4135168-1-glider@google.com
Fixes: b073d7f8ae ("mm: kmsan: maintain KMSAN metadata for page operations")
Signed-off-by: Alexander Potapenko <glider@google.com>
Reported-by: Dipanjan Das <mail.dipanjan.das@gmail.com>
  Link: https://lore.kernel.org/linux-mm/CANX2M5ZRrRA64k0hOif02TjmY9kbbO2aCBPyq79es34RXZ=cAw@mail.gmail.com/
Reviewed-by: Marco 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: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Alexander Potapenko
2023-04-13 15:12:20 +02:00
committed by Andrew Morton
parent a101482421
commit 47ebd0310e
3 changed files with 34 additions and 19 deletions
Download Patch File Download Diff File Expand all files Collapse all files

20
include/linux/kmsan.h
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@@ -134,11 +134,12 @@ void kmsan_kfree_large(const void *ptr);
* @page_shift: page_shift passed to vmap_range_noflush().
*
* KMSAN maps shadow and origin pages of @pages into contiguous ranges in
* vmalloc metadata address range.
* vmalloc metadata address range. Returns 0 on success, callers must check
* for non-zero return value.
*/
void kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end,
pgprot_t prot, struct page **pages,
unsigned int page_shift);
int kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end,
pgprot_t prot, struct page **pages,
unsigned int page_shift);
/**
* kmsan_vunmap_kernel_range_noflush() - Notify KMSAN about a vunmap.
@@ -281,12 +282,13 @@ static inline void kmsan_kfree_large(const void *ptr)
{
}
static inline void kmsan_vmap_pages_range_noflush(unsigned long start,
unsigned long end,
pgprot_t prot,
struct page **pages,
unsigned int page_shift)
static inline int kmsan_vmap_pages_range_noflush(unsigned long start,
unsigned long end,
pgprot_t prot,
struct page **pages,
unsigned int page_shift)
{
return 0;
}
static inline void kmsan_vunmap_range_noflush(unsigned long start,