The patch titled
Subject: resource: fix locking in find_next_iomem_res()
has been added to the -mm tree. Its filename is
resource-fix-locking-in-find_next_iomem_res.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/resource-fix-locking-in-find_next_iomem_res.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/resource-fix-locking-in-find_next_iomem_res.patch
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------------------------------------------------------
From: Nadav Amit <namit@xxxxxxxxxx>
Subject: resource: fix locking in find_next_iomem_res()
Since resources can be removed, locking should ensure that the resource is
not removed while accessing it. However, find_next_iomem_res() does not
hold the lock while copying the data of the resource.
Keep holding the lock while the data is copied. While at it, change the
return value to a more informative value. It is disregarded by the
callers.
Link: http://lkml.kernel.org/r/20190613045903.4922-2-namit@xxxxxxxxxx
Fixes: ff3cc952d3f00 ("resource: Add remove_resource interface")
Signed-off-by: Nadav Amit <namit@xxxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: Toshi Kani <toshi.kani@xxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/resource.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
--- a/kernel/resource.c~resource-fix-locking-in-find_next_iomem_res
+++ a/kernel/resource.c
@@ -365,16 +365,16 @@ static int find_next_iomem_res(resource_
break;
}
- read_unlock(&resource_lock);
- if (!p)
- return -1;
+ if (p) {
+ /* copy data */
+ res->start = max(start, p->start);
+ res->end = min(end, p->end);
+ res->flags = p->flags;
+ res->desc = p->desc;
+ }
- /* copy data */
- res->start = max(start, p->start);
- res->end = min(end, p->end);
- res->flags = p->flags;
- res->desc = p->desc;
- return 0;
+ read_unlock(&resource_lock);
+ return p ? 0 : -ENODEV;
}
static int __walk_iomem_res_desc(resource_size_t start, resource_size_t end,
_
Patches currently in -mm which might be from namit@xxxxxxxxxx are
resource-fix-locking-in-find_next_iomem_res.patch
resource-avoid-unnecessary-lookups-in-find_next_iomem_res.patch
resource-introduce-resource-cache.patch
