From: Nadav Amit <namit@vmware.com>
Date: Thu, 18 Jul 2019 15:57:31 -0700
Subject: resource: fix locking in find_next_iomem_res()
Git-commit: 49f17c26c123b60fd1c74629eef077740d16ffc2
Patch-mainline: v5.3-rc1
References: bsc#1114279
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>
Acked-by: Borislav Petkov <bp@suse.de>
---
kernel/resource.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -392,16 +392,16 @@ 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,