Messages in this thread | | | Date | Thu, 12 Dec 2019 14:05:39 +0100 | From | Sebastian Andrzej Siewior <> | Subject | Re: [PATCH] of: Rework and simplify phandle cache to use a fixed size |
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On 2019-12-11 17:48:54 [-0600], Rob Herring wrote: > > - if (phandle_cache) { > > - if (phandle_cache[masked_handle] && > > - handle == phandle_cache[masked_handle]->phandle) > > - np = phandle_cache[masked_handle]; > > - if (np && of_node_check_flag(np, OF_DETACHED)) { > > - WARN_ON(1); /* did not uncache np on node removal */ > > - of_node_put(np); > > - phandle_cache[masked_handle] = NULL; > > - np = NULL; > > - } > > + if (phandle_cache[handle_hash] && > > + handle == phandle_cache[handle_hash]->phandle) > > + np = phandle_cache[handle_hash]; > > + if (np && of_node_check_flag(np, OF_DETACHED)) { > > + WARN_ON(1); /* did not uncache np on node removal */ > > BTW, I don't think this check is even valid. If we failed to detach > and remove the node from the cache, then we could be accessing np > after freeing it.
this is kmalloc()ed memory which is always valid. If the memory is already re-used then handle == phandle_cache[handle_hash]->phandle
will fail (the check, not the memory access itself). If the check remains valid then you can hope for the OF_DETACHED flag to trigger the warning.
> Rob
Sebastian
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