Commit 9935d7ed authored Jul 19, 2019 by Joerg Roedel Committed by Greg Kroah-Hartman Aug 16, 2019

x86/mm: Sync also unmappings in vmalloc_sync_all()



commit 8e998fc24de47c55b47a887f6c95ab91acd4a720 upstream.

With huge-page ioremap areas the unmappings also need to be synced between
all page-tables. Otherwise it can cause data corruption when a region is
unmapped and later re-used.

Make the vmalloc_sync_one() function ready to sync unmappings and make sure
vmalloc_sync_all() iterates over all page-tables even when an unmapped PMD
is found.

Fixes: 5d72b4fb ('x86, mm: support huge I/O mapping capability I/F')
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/20190719184652.11391-3-joro@8bytes.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent dd524d48

arch/x86/mm/fault.c

+5 −8

Original line number	Diff line number	Diff line
		@@ -261,11 +261,12 @@ static inline pmd_t vmalloc_sync_one(pgd_t pgd, unsigned long address)

		pmd = pmd_offset(pud, address);
		pmd_k = pmd_offset(pud_k, address);
		if (!pmd_present(*pmd_k))
		return NULL;

		if (!pmd_present(*pmd))
		if (pmd_present(pmd) != pmd_present(pmd_k))
		set_pmd(pmd, *pmd_k);

		if (!pmd_present(*pmd_k))
		return NULL;
		else
		BUG_ON(pmd_pfn(pmd) != pmd_pfn(pmd_k));

		@@ -287,17 +288,13 @@ void vmalloc_sync_all(void)
		spin_lock(&pgd_lock);
		list_for_each_entry(page, &pgd_list, lru) {
		spinlock_t *pgt_lock;
		pmd_t *ret;

		/* the pgt_lock only for Xen */
		pgt_lock = &pgd_page_get_mm(page)->page_table_lock;

		spin_lock(pgt_lock);
		ret = vmalloc_sync_one(page_address(page), address);
		vmalloc_sync_one(page_address(page), address);
		spin_unlock(pgt_lock);

		if (!ret)
		break;
		}
		spin_unlock(&pgd_lock);
		}