4.9-stable review patch. If anyone has any objections, please let me know.
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From: Dan Williams dan.j.williams@intel.com
[ Upstream commit 8b06b884cd98f7ec8b5028680b99fabfb7b3e192 ]
Keep the nfit_test instances alive until after nfit_test_teardown(), as we may be doing resource lookups until the final un-registrations have completed. This fixes crashes of the form.
BUG: unable to handle kernel NULL pointer dereference at 0000000000000038 IP: __release_resource+0x12/0x90 Call Trace: remove_resource+0x23/0x40 __wrap_remove_resource+0x29/0x30 [nfit_test_iomap] acpi_nfit_remove_resource+0xe/0x10 [nfit] devm_action_release+0xf/0x20 release_nodes+0x16d/0x2b0 devres_release_all+0x3c/0x60 device_release+0x21/0x90 kobject_release+0x6a/0x170 kobject_put+0x2f/0x60 put_device+0x17/0x20 platform_device_unregister+0x20/0x30 nfit_test_exit+0x36/0x960 [nfit_test]
Reported-by: Linda Knippers linda.knippers@hpe.com Signed-off-by: Dan Williams dan.j.williams@intel.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/testing/nvdimm/test/nfit.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
--- a/tools/testing/nvdimm/test/nfit.c +++ b/tools/testing/nvdimm/test/nfit.c @@ -1908,6 +1908,7 @@ static __init int nfit_test_init(void) put_device(&pdev->dev); goto err_register; } + get_device(&pdev->dev);
rc = dma_coerce_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64)); if (rc) @@ -1926,6 +1927,10 @@ static __init int nfit_test_init(void) if (instances[i]) platform_device_unregister(&instances[i]->pdev); nfit_test_teardown(); + for (i = 0; i < NUM_NFITS; i++) + if (instances[i]) + put_device(&instances[i]->pdev.dev); + return rc; }
@@ -1933,10 +1938,13 @@ static __exit void nfit_test_exit(void) { int i;
- platform_driver_unregister(&nfit_test_driver); for (i = 0; i < NUM_NFITS; i++) platform_device_unregister(&instances[i]->pdev); + platform_driver_unregister(&nfit_test_driver); nfit_test_teardown(); + + for (i = 0; i < NUM_NFITS; i++) + put_device(&instances[i]->pdev.dev); class_destroy(nfit_test_dimm); }