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| author | Nadav Amit <namit@vmware.com> | 2019-07-19 00:57:31 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-07-19 02:08:06 +0200 |
| commit | 49f17c26c123b60fd1c74629eef077740d16ffc2 (patch) | |
| tree | 2cb82f376c2f79d4cf299b853e8ff8c1f683727b /kernel/resource.c | |
| parent | mm: thp: fix false negative of shmem vma's THP eligibility (diff) | |
| download | linux-49f17c26c123b60fd1c74629eef077740d16ffc2.tar.xz linux-49f17c26c123b60fd1c74629eef077740d16ffc2.zip | |
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 '')
| -rw-r--r-- | kernel/resource.c | 20 |
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, |