From 6a84fb4b4e439a8ef0ce19ec7e7661ad76f655c9 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Fri, 28 Oct 2016 14:34:51 -0700 Subject: [PATCH] device-dax: check devm_nsio_enable() return value If the dax_pmem driver is passed a resource that is already busy the driver probe attempt should fail with a message like the following: dax_pmem dax0.1: could not reserve region [mem 0x100000000-0x11fffffff] However, if we do not catch the error we crash for the obvious reason of accessing memory that is not mapped. BUG: unable to handle kernel paging request at ffffc90020001000 IP: [] __memcpy+0x12/0x20 [..] Call Trace: [] ? nsio_rw_bytes+0x60/0x180 [] nd_pfn_validate+0x75/0x320 [] nvdimm_setup_pfn+0xb9/0x5d0 [] ? devm_nsio_enable+0xff/0x110 [] dax_pmem_probe+0x59/0x260 Cc: Fixes: ab68f2622136 ("/dev/dax, pmem: direct access to persistent memory") Reported-by: Dave Hansen Signed-off-by: Dan Williams --- drivers/dax/pmem.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c index 4a15fa5df98b..73c6ce93a0d9 100644 --- a/drivers/dax/pmem.c +++ b/drivers/dax/pmem.c @@ -78,7 +78,9 @@ static int dax_pmem_probe(struct device *dev) nsio = to_nd_namespace_io(&ndns->dev); /* parse the 'pfn' info block via ->rw_bytes */ - devm_nsio_enable(dev, nsio); + rc = devm_nsio_enable(dev, nsio); + if (rc) + return rc; altmap = nvdimm_setup_pfn(nd_pfn, &res, &__altmap); if (IS_ERR(altmap)) return PTR_ERR(altmap);