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Commit 0d39e266 authored by Andrey Ryabinin's avatar Andrey Ryabinin Committed by Thomas Gleixner
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x86/kasan: Panic if there is not enough memory to boot 



Currently KASAN doesn't panic in case it don't have enough memory
to boot. Instead, it crashes in some random place:

 kernel BUG at arch/x86/mm/physaddr.c:27!

 RIP: 0010:__phys_addr+0x268/0x276
 Call Trace:
  kasan_populate_shadow+0x3f2/0x497
  kasan_init+0x12e/0x2b2
  setup_arch+0x2825/0x2a2c
  start_kernel+0xc8/0x15f4
  x86_64_start_reservations+0x2a/0x2c
  x86_64_start_kernel+0x72/0x75
  secondary_startup_64+0xa5/0xb0

Use memblock_virt_alloc_try_nid() for allocations without failure
fallback. It will panic with an out of memory message.

Reported-by: default avatarkernel test robot <xiaolong.ye@intel.com>
Signed-off-by: default avatarAndrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarDmitry Vyukov <dvyukov@google.com>
Cc: kasan-dev@googlegroups.com
Cc: Alexander Potapenko <glider@google.com>
Cc: lkp@01.org
Link: https://lkml.kernel.org/r/20180110153602.18919-1-aryabinin@virtuozzo.com
parent b8b9ce4b

arch/x86/mm/kasan_init_64.c

+14 −10
Original line number Diff line number Diff line
@@ -21,8 +21,12 @@ extern struct range pfn_mapped[E820_MAX_ENTRIES]; 


static p4d_t tmp_p4d_table[PTRS_PER_P4D] __initdata __aligned(PAGE_SIZE);



static __init void *early_alloc(size_t size, int nid)

static __init void *early_alloc(size_t size, int nid, bool panic)

{

	if (panic)

		return memblock_virt_alloc_try_nid(size, size,

			__pa(MAX_DMA_ADDRESS), BOOTMEM_ALLOC_ACCESSIBLE, nid);

	else

		return memblock_virt_alloc_try_nid_nopanic(size, size,

			__pa(MAX_DMA_ADDRESS), BOOTMEM_ALLOC_ACCESSIBLE, nid);

}
@@ -38,14 +42,14 @@ static void __init kasan_populate_pmd(pmd_t *pmd, unsigned long addr, 
		if (boot_cpu_has(X86_FEATURE_PSE) &&

		    ((end - addr) == PMD_SIZE) &&

		    IS_ALIGNED(addr, PMD_SIZE)) {

			p = early_alloc(PMD_SIZE, nid);

			p = early_alloc(PMD_SIZE, nid, false);

			if (p && pmd_set_huge(pmd, __pa(p), PAGE_KERNEL))

				return;

			else if (p)

				memblock_free(__pa(p), PMD_SIZE);

		}



		p = early_alloc(PAGE_SIZE, nid);

		p = early_alloc(PAGE_SIZE, nid, true);

		pmd_populate_kernel(&init_mm, pmd, p);

	}
@@ -57,7 +61,7 @@ static void __init kasan_populate_pmd(pmd_t *pmd, unsigned long addr, 
		if (!pte_none(*pte))

			continue;



		p = early_alloc(PAGE_SIZE, nid);

		p = early_alloc(PAGE_SIZE, nid, true);

		entry = pfn_pte(PFN_DOWN(__pa(p)), PAGE_KERNEL);

		set_pte_at(&init_mm, addr, pte, entry);

	} while (pte++, addr += PAGE_SIZE, addr != end);
@@ -75,14 +79,14 @@ static void __init kasan_populate_pud(pud_t *pud, unsigned long addr, 
		if (boot_cpu_has(X86_FEATURE_GBPAGES) &&

		    ((end - addr) == PUD_SIZE) &&

		    IS_ALIGNED(addr, PUD_SIZE)) {

			p = early_alloc(PUD_SIZE, nid);

			p = early_alloc(PUD_SIZE, nid, false);

			if (p && pud_set_huge(pud, __pa(p), PAGE_KERNEL))

				return;

			else if (p)

				memblock_free(__pa(p), PUD_SIZE);

		}



		p = early_alloc(PAGE_SIZE, nid);

		p = early_alloc(PAGE_SIZE, nid, true);

		pud_populate(&init_mm, pud, p);

	}
@@ -101,7 +105,7 @@ static void __init kasan_populate_p4d(p4d_t *p4d, unsigned long addr, 
	unsigned long next;



	if (p4d_none(*p4d)) {

		void *p = early_alloc(PAGE_SIZE, nid);

		void *p = early_alloc(PAGE_SIZE, nid, true);



		p4d_populate(&init_mm, p4d, p);

	}
@@ -122,7 +126,7 @@ static void __init kasan_populate_pgd(pgd_t *pgd, unsigned long addr, 
	unsigned long next;



	if (pgd_none(*pgd)) {

		p = early_alloc(PAGE_SIZE, nid);

		p = early_alloc(PAGE_SIZE, nid, true);

		pgd_populate(&init_mm, pgd, p);

	}