[ Upstream commit 49f17c26c123b60fd1c74629eef077740d16ffc2 ] 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. [[email protected]: fix find_next_iomem_res() documentation] Link: http://lkml.kernel.org/r/[email protected] Fixes: ff3cc952d3f00 ("resource: Add remove_resource interface") Signed-off-by: Nadav Amit <[email protected]> Reviewed-by: Andrew Morton <[email protected]> Reviewed-by: Dan Williams <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Toshi Kani <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Bjorn Helgaas <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Sasha Levin <[email protected]> --- kernel/resource.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/kernel/resource.c b/kernel/resource.c index 38b8d11c9eaf4..bce773cc5e416 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -325,7 +325,7 @@ 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. + * -ENODEV. Returns -EINVAL for invalid parameters. * * This function walks the whole tree and not just first level children * unless @first_level_children_only is true. @@ -359,16 +359,16 @@ 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, -- 2.20.1
