From: Paolo 'Blaisorblade' Giarrusso <[email protected]>
We got unflushed PTE's marked up-to-date, because they were protected to get
dirtying / accessing faults. So, don't test the PTE for being up-to-date, but
check directly the permission (since the PTE is not protected for that).
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <[email protected]>
---
linux-2.6.git-paolo/arch/um/kernel/trap_kern.c | 28 +++++++++++++++++++------
1 files changed, 22 insertions(+), 6 deletions(-)
diff -puN arch/um/kernel/trap_kern.c~rfp-sigsegv-uml-3-fix arch/um/kernel/trap_kern.c
--- linux-2.6.git/arch/um/kernel/trap_kern.c~rfp-sigsegv-uml-3-fix 2005-08-11 23:14:58.000000000 +0200
+++ linux-2.6.git-paolo/arch/um/kernel/trap_kern.c 2005-08-11 23:14:58.000000000 +0200
@@ -35,7 +35,7 @@ int handle_page_fault(unsigned long addr
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
- pte_t *pte;
+ pte_t *pte, entry;
int err = -EFAULT;
int access_mask = 0;
@@ -75,16 +75,32 @@ handle_fault:
err = -EACCES;
goto out;
case VM_FAULT_SIGSEGV:
+ WARN_ON(!(vma->vm_flags & VM_NONUNIFORM));
/* Duplicate this code here. */
pgd = pgd_offset(mm, address);
pud = pud_offset(pgd, address);
pmd = pmd_offset(pud, address);
pte = pte_offset_kernel(pmd, address);
- if (likely (pte_newpage(*pte) || pte_newprot(*pte))) {
- /* This wasn't done by __handle_mm_fault(), and
- * the page hadn't been flushed. */
- *pte = pte_mkyoung(*pte);
- if(pte_write(*pte)) *pte = pte_mkdirty(*pte);
+ if (likely (pte_newpage(*pte) || pte_newprot(*pte)) ||
+ (is_write ? pte_write(*pte) : pte_read(*pte)) ) {
+ /* The page hadn't been flushed, or it had been
+ * flushed but without access to get a dirtying
+ * / accessing fault. */
+
+ /* __handle_mm_fault() didn't dirty / young this
+ * PTE, probably we won't get another fault for
+ * this page, so fix things now. */
+ entry = *pte;
+ entry = pte_mkyoung(*pte);
+ if(pte_write(entry))
+ entry = pte_mkdirty(entry);
+ /* Yes, this will set the page as NEWPAGE. We
+ * want this, otherwise things won't work.
+ * Indeed, the
+ * *pte = pte_mkyoung(*pte);
+ * we used to have (uselessly) didn't work at
+ * all! */
+ set_pte(pte, entry);
break;
} else {
err = -EFAULT;
_
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
| |
 |