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0b5a50635f
When RANDOMIZE_BASE (KASLR) is enabled; or the sum of all loaded
modules exceeds 512 MiB, then loading modules fails with a warning
(and hence a vmalloc allocation failure) because the PTEs for the
newly-allocated vmalloc address space are not zero.
WARNING: CPU: 0 PID: 494 at linux/mm/vmalloc.c:128
vmap_page_range_noflush+0x2a1/0x360()
This is caused by xen_setup_kernel_pagetables() copying
level2_kernel_pgt into level2_fixmap_pgt, overwriting many non-present
entries.
Without KASLR, the normal kernel image size only covers the first half
of level2_kernel_pgt and module space starts after that.
L4[511]->level3_kernel_pgt[510]->level2_kernel_pgt[ 0..255]->kernel
[256..511]->module
[511]->level2_fixmap_pgt[ 0..505]->module
This allows 512 MiB of of module vmalloc space to be used before
having to use the corrupted level2_fixmap_pgt entries.
With KASLR enabled, the kernel image uses the full PUD range of 1G and
module space starts in the level2_fixmap_pgt. So basically:
L4[511]->level3_kernel_pgt[510]->level2_kernel_pgt[0..511]->kernel
[511]->level2_fixmap_pgt[0..505]->module
And now no module vmalloc space can be used without using the corrupt
level2_fixmap_pgt entries.
Fix this by properly converting the level2_fixmap_pgt entries to MFNs,
and setting level1_fixmap_pgt as read-only.
A number of comments were also using the the wrong L3 offset for
level2_kernel_pgt. These have been corrected.
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: stable@vger.kernel.org
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| .. | ||
| apic.c | ||
| debugfs.c | ||
| debugfs.h | ||
| efi.c | ||
| enlighten.c | ||
| grant-table.c | ||
| irq.c | ||
| Kconfig | ||
| Makefile | ||
| mmu.c | ||
| mmu.h | ||
| multicalls.c | ||
| multicalls.h | ||
| p2m.c | ||
| pci-swiotlb-xen.c | ||
| platform-pci-unplug.c | ||
| setup.c | ||
| smp.c | ||
| smp.h | ||
| spinlock.c | ||
| suspend.c | ||
| time.c | ||
| trace.c | ||
| vdso.h | ||
| vga.c | ||
| xen-asm_32.S | ||
| xen-asm_64.S | ||
| xen-asm.h | ||
| xen-asm.S | ||
| xen-head.S | ||
| xen-ops.h | ||