Messages in this thread | | | From | Dan Williams <> | Date | Mon, 10 Sep 2018 23:02:11 -0700 | Subject | Re: [PATCH] device-dax: avoid hang on error before devm_memremap_pages() |
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On Tue, Jul 31, 2018 at 5:26 PM, Dave Jiang <dave.jiang@intel.com> wrote: > > > On 7/31/2018 7:32 AM, Stefan Hajnoczi wrote: >> >> dax_pmem_percpu_exit() waits for dax_pmem_percpu_release() to invoke the >> dax_pmem->cmp completion. Unfortunately this approach to cleaning up >> the percpu_ref only works after devm_memremap_pages() was successful. >> >> If devm_add_action_or_reset() or devm_memremap_pages() fails, >> dax_pmem_percpu_release() is not invoked. Therefore >> dax_pmem_percpu_exit() hangs waiting for the completion: >> >> rc = devm_add_action_or_reset(dev, dax_pmem_percpu_exit, >> &dax_pmem->ref); >> if (rc) >> return rc; >> >> dax_pmem->pgmap.ref = &dax_pmem->ref; >> addr = devm_memremap_pages(dev, &dax_pmem->pgmap); >> >> Avoid the hang by calling percpu_ref_exit() in the error paths instead >> of going through dax_pmem_percpu_exit(). >> >> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> > > > Applied >
A similar problem exists in other devm_memremap_pages() users. I had a more comprehensive fix in-flight that I will rebase on top of this change.
https://lore.kernel.org/patchwork/patch/961576/
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