diff options
| author | Rusty Russell <rusty@rustcorp.com.au> | 2009-03-31 05:55:23 +0200 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2009-03-30 13:25:24 +0200 |
| commit | b7ff99ea53cd16de8f6166c0e98f19a7c6ca67ee (patch) | |
| tree | fed5a3cf8fc8061967e60b5bbf32e81f3c742822 /arch/x86/lguest | |
| parent | lguest: fix spurious BUG_ON() on invalid guest stack. (diff) | |
| download | linux-b7ff99ea53cd16de8f6166c0e98f19a7c6ca67ee.tar.xz linux-b7ff99ea53cd16de8f6166c0e98f19a7c6ca67ee.zip | |
lguest: wire up pte_update/pte_update_defer
Impact: intermittent guest segv/crash fix
I've been seeing random guest bad address crashes and segmentation faults:
bisect led to 4f98a2fee8 (vmscan: split LRU lists into anon & file sets),
but that's a red herring.
It turns out that lguest never hooked up the pte_update/pte_update_defer
calls, so our ptes were not always in sync. After the vmscan commit, the
bug became reproducible; now a fsck in a 64MB guest causes reproducible
pagetable corruption.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: jeremy@xensource.com
Cc: virtualization@lists.osdl.org
Cc: stable@kernel.org
Diffstat (limited to 'arch/x86/lguest')
| -rw-r--r-- | arch/x86/lguest/boot.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c index 9fe4ddaa8f6f..7822d29b02c7 100644 --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -490,11 +490,17 @@ static void lguest_write_cr4(unsigned long val) * into a process' address space. We set the entry then tell the Host the * toplevel and address this corresponds to. The Guest uses one pagetable per * process, so we need to tell the Host which one we're changing (mm->pgd). */ +static void lguest_pte_update(struct mm_struct *mm, unsigned long addr, + pte_t *ptep) +{ + lazy_hcall(LHCALL_SET_PTE, __pa(mm->pgd), addr, ptep->pte_low); +} + static void lguest_set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pteval) { *ptep = pteval; - lazy_hcall(LHCALL_SET_PTE, __pa(mm->pgd), addr, pteval.pte_low); + lguest_pte_update(mm, addr, ptep); } /* The Guest calls this to set a top-level entry. Again, we set the entry then @@ -1040,6 +1046,8 @@ __init void lguest_init(void) pv_mmu_ops.read_cr3 = lguest_read_cr3; pv_mmu_ops.lazy_mode.enter = paravirt_enter_lazy_mmu; pv_mmu_ops.lazy_mode.leave = lguest_leave_lazy_mode; + pv_mmu_ops.pte_update = lguest_pte_update; + pv_mmu_ops.pte_update_defer = lguest_pte_update; #ifdef CONFIG_X86_LOCAL_APIC /* apic read/write intercepts */ |