The patch titled
Subject: mm/vmalloc.c: add an error message if two areas overlap
has been added to the -mm tree. Its filename is
mm-vmallocc-add-an-error-message-if-two-areas-overlap.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-vmallocc-add-an-error-message-if-two-areas-overlap.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-vmallocc-add-an-error-message-if-two-areas-overlap.patch
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------------------------------------------------------
From: "Uladzislau Rezki (Sony)" <urezki@xxxxxxxxx>
Subject: mm/vmalloc.c: add an error message if two areas overlap
Before triggering a BUG() it would be useful to understand how two areas
overlap between each other. Print information about start/end addresses
of both VAs and their addresses.
For example if both are identical it could mean double free.
Link: http://lkml.kernel.org/r/20200710194443.2984-1-urezki@xxxxxxxxx
Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
Cc: Hillf Danton <hdanton@xxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@xxxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmalloc.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- a/mm/vmalloc.c~mm-vmallocc-add-an-error-message-if-two-areas-overlap
+++ a/mm/vmalloc.c
@@ -550,8 +550,13 @@ find_va_links(struct vmap_area *va,
else if (va->va_end > tmp_va->va_start &&
va->va_start >= tmp_va->va_end)
link = &(*link)->rb_right;
- else
+ else {
+ pr_err("Overlaps: 0x%px(0x%lx-0x%lx), 0x%px(0x%lx-0x%lx)\n",
+ va, va->va_start, va->va_end, tmp_va,
+ tmp_va->va_start, tmp_va->va_end);
+
BUG();
+ }
} while (*link);
*parent = &tmp_va->rb_node;
_
Patches currently in -mm which might be from urezki@xxxxxxxxx are
mm-vmalloc-simplify-merge_or_add_vmap_area-func.patch
mm-vmalloc-simplify-augment_tree_propagate_check-func.patch
mm-vmalloc-switch-to-propagate-callback.patch
mm-vmalloc-update-the-header-about-kva-rework.patch
mm-vmallocc-add-an-error-message-if-two-areas-overlap.patch
