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authorNadav Amit <namit@vmware.com>2019-07-18 15:57:31 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-18 17:08:06 -0700
commit49f17c26c123b60fd1c74629eef077740d16ffc2 (patch)
tree2cb82f376c2f79d4cf299b853e8ff8c1f683727b /kernel
parentc06306696f8368b08774e2a743dbc52d92a61693 (diff)
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. [akpm@linux-foundation.org: fix find_next_iomem_res() documentation] Link: http://lkml.kernel.org/r/20190613045903.4922-2-namit@vmware.com Fixes: ff3cc952d3f00 ("resource: Add remove_resource interface") Signed-off-by: Nadav Amit <namit@vmware.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/resource.c20
1 files changed, 10 insertions, 10 deletions
diff --git a/kernel/resource.c b/kernel/resource.c
index d22423e85cf8..3ced0cd45bdd 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -326,7 +326,7 @@ EXPORT_SYMBOL(release_resource);
*
* If a resource is found, returns 0 and @*res is overwritten with the part
* of the resource that's within [@start..@end]; if none is found, returns
- * -1 or -EINVAL for other invalid parameters.
+ * -ENODEV. Returns -EINVAL for invalid parameters.
*
* This function walks the whole tree and not just first level children
* unless @first_lvl is true.
@@ -365,16 +365,16 @@ static int find_next_iomem_res(resource_size_t start, resource_size_t end,
break;
}
+ if (p) {
+ /* copy data */
+ res->start = max(start, p->start);
+ res->end = min(end, p->end);
+ res->flags = p->flags;
+ res->desc = p->desc;
+ }
+
read_unlock(&resource_lock);
- if (!p)
- return -1;
-
- /* copy data */
- res->start = max(start, p->start);
- res->end = min(end, p->end);
- res->flags = p->flags;
- res->desc = p->desc;
- return 0;
+ return p ? 0 : -ENODEV;
}
static int __walk_iomem_res_desc(resource_size_t start, resource_size_t end,