Messages in this thread | | | From | Linus Torvalds <> | Date | Fri, 9 Aug 2019 15:45:59 -0700 | Subject | Re: Resend [PATCH] kernel/resource.c: invalidate parent when freed resource has childs |
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On Fri, Aug 9, 2019 at 3:38 PM Wei Yang <richard.weiyang@gmail.com> wrote: > > In theory, child may have siblings. Would it be possible to have several > devices under xhci-hcd?
I'm less interested in the xhci-hcd case - which I certainly *hope* is fixed already? - than in "if this happens somewhere else".
So if we do want to remove the parent (which may be a good idea with a warning), and want to make sure that the children are really removed from the resource hierarchy, we should do somethiing like
static bool detach_children(struct resource *res) { res = res->child; if (!res) return false; do { res->parent = NULL; res = res->sibling; } while (res); return true; }
and then we could write the __release_region() warning as
/* You should not release a resource that has children */ WARN_ON_ONCE(detach_children(res));
or something?
NOTE! The above is entirely untested, and written purely in my mail reader. It might be seriously buggy, including not compiling, or doing odd things. See it more as a "maybe something like this" code snippet example than any kind of final form.
Linus
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