The patch titled
Subject: mm, writeback: prevent race when calculating dirty limits
has been removed from the -mm tree. Its filename was
mm-writeback-prevent-race-when-calculating-dirty-limits.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: David Rientjes <rientjes@xxxxxxxxxx>
Subject: mm, writeback: prevent race when calculating dirty limits
Setting vm_dirty_bytes and dirty_background_bytes is not protected by any
serialization.
Therefore, it's possible for either variable to change value after the
test in global_dirty_limits() to determine whether available_memory needs
to be initialized or not.
Always ensure that available_memory is properly initialized.
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page-writeback.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff -puN mm/page-writeback.c~mm-writeback-prevent-race-when-calculating-dirty-limits mm/page-writeback.c
--- a/mm/page-writeback.c~mm-writeback-prevent-race-when-calculating-dirty-limits
+++ a/mm/page-writeback.c
@@ -261,14 +261,11 @@ static unsigned long global_dirtyable_me
*/
void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty)
{
+ const unsigned long available_memory = global_dirtyable_memory();
unsigned long background;
unsigned long dirty;
- unsigned long uninitialized_var(available_memory);
struct task_struct *tsk;
- if (!vm_dirty_bytes || !dirty_background_bytes)
- available_memory = global_dirtyable_memory();
-
if (vm_dirty_bytes)
dirty = DIV_ROUND_UP(vm_dirty_bytes, PAGE_SIZE);
else
_
Patches currently in -mm which might be from rientjes@xxxxxxxxxx are
origin.patch
x86-numa-setup_node_data-drop-dead-code-and-rename-function.patch
x86-numa-setup_node_data-drop-dead-code-and-rename-function-v2.patch
mm-hugetlb-take-refcount-under-page-table-lock-in-follow_huge_pmd.patch
mm-hugetlb-use-get_page_unless_zero-in-hugetlb_fault.patch
mm-hugetlb-add-migration-entry-check-in-hugetlb_change_protection.patch
mm-hugetlb-remove-unused-argument-of-follow_huge_pmdpud.patch
include-kernelh-rewrite-min3-max3-and-clamp-using-min-and-max.patch
mm-utilc-add-kstrimdup.patch
fs-proc-kcorec-use-page_align-instead-of-alignpage_size.patch
fork-exec-cleanup-mm-initialization.patch
fork-reset-mm-pinned_vm.patch
fork-copy-mms-vm-usage-counters-under-mmap_sem.patch
linux-next.patch
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