From: Stefan Hajnoczi stefanha@redhat.com
[ Upstream commit b7751410c180a05fdc21268f8661b1480169b0df ]
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 Signed-off-by: Dave Jiang dave.jiang@intel.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- drivers/dax/pmem.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c index fd49b24fd6af..99e2aace8078 100644 --- a/drivers/dax/pmem.c +++ b/drivers/dax/pmem.c @@ -105,15 +105,19 @@ static int dax_pmem_probe(struct device *dev) if (rc) return rc;
- rc = devm_add_action_or_reset(dev, dax_pmem_percpu_exit, - &dax_pmem->ref); - if (rc) + rc = devm_add_action(dev, dax_pmem_percpu_exit, &dax_pmem->ref); + if (rc) { + percpu_ref_exit(&dax_pmem->ref); return rc; + }
dax_pmem->pgmap.ref = &dax_pmem->ref; addr = devm_memremap_pages(dev, &dax_pmem->pgmap); - if (IS_ERR(addr)) + if (IS_ERR(addr)) { + devm_remove_action(dev, dax_pmem_percpu_exit, &dax_pmem->ref); + percpu_ref_exit(&dax_pmem->ref); return PTR_ERR(addr); + }
rc = devm_add_action_or_reset(dev, dax_pmem_percpu_kill, &dax_pmem->ref);