The patch titled
     mm-dnp-invp-race-fix2
has been added to the -mm tree.  Its filename is
     mm-fix-fault-vs-invalidate-race-for-linear-mappings-fix.patch

*** Remember to use Documentation/SubmitChecklist when testing your code ***

See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this

------------------------------------------------------
Subject: mm-dnp-invp-race-fix2
From: Nick Piggin <[EMAIL PROTECTED]>

The nopage vs invalidate race fix patch did not take care of truncating
private COW pages. Mind you, I'm pretty sure this was previously racy
even for regular truncate, not to mention vmtruncate_range.


Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
---

 mm/memory.c |   13 +++++++++++++
 1 file changed, 13 insertions(+)

diff -puN mm/memory.c~mm-fix-fault-vs-invalidate-race-for-linear-mappings-fix 
mm/memory.c
--- a/mm/memory.c~mm-fix-fault-vs-invalidate-race-for-linear-mappings-fix
+++ a/mm/memory.c
@@ -1905,7 +1905,18 @@ int vmtruncate(struct inode * inode, lof
        if (IS_SWAPFILE(inode))
                goto out_busy;
        i_size_write(inode, offset);
+
+       /*
+        * unmap_mapping_range is called twice, first simply for efficiency
+        * so that truncate_inode_pages does fewer single-page unmaps. However
+        * after this first call, and before truncate_inode_pages finishes,
+        * it is possible for private pages to be COWed, which remain after
+        * truncate_inode_pages finishes, hence the second unmap_mapping_range
+        * call must be made for correctness.
+        */
+       unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
        truncate_inode_pages(mapping, offset);
+       unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
        goto out_truncate;
 
 do_expand:
@@ -1943,7 +1954,9 @@ int vmtruncate_range(struct inode *inode
 
        mutex_lock(&inode->i_mutex);
        down_write(&inode->i_alloc_sem);
+       unmap_mapping_range(mapping, offset, (end - offset), 1);
        truncate_inode_pages_range(mapping, offset, end);
+       unmap_mapping_range(mapping, offset, (end - offset), 1);
        inode->i_op->truncate_range(inode, offset, end);
        up_write(&inode->i_alloc_sem);
        mutex_unlock(&inode->i_mutex);
_

Patches currently in -mm which might be from [EMAIL PROTECTED] are

origin.patch
mm-fix-fault-vs-invalidate-race-for-linear-mappings-fix.patch
mm-merge-nopfn-into-fault-fix.patch
cpuset-remove-sched-domain-hooks-from-cpusets.patch
freezer-task-exit_state-should-be-treated-as-bolean.patch
splice-partial-write-handling-fix.patch
as-fix-antic_expire-check.patch
kblockd-use-flush_work.patch
sched-fix-idle-load-balancing-in-softirqd-context.patch
sched-dynticks-idle-load-balancing-v3.patch
sched-optimize-siblings-status-check-logic-in-wake_idle.patch
sched2-sched-domain-sysctl.patch
lists-add-list-splice-tail.patch
sched-remove-sleepavg-from-proc.patch
sched-remove-noninteractive-flag.patch
sched-implement-rsdl-cpu-scheduler.patch
sched-document-rsdl-cpu-scheduler.patch

-
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to