From e471486c13b82b1338d49c798f78bb62b1ed0a9e Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Thu, 2 Feb 2017 10:31:00 -0800 Subject: [PATCH] acpi, nfit: fix acpi_nfit_flush_probe() crash We queue an on-stack work item to 'nfit_wq' and wait for it to complete as part of a 'flush_probe' request. However, if the user cancels the wait we need to make sure the item is flushed from the queue otherwise we are leaving an out-of-scope stack address on the work list. BUG: unable to handle kernel paging request at ffffbcb3c72f7cd0 IP: [] __list_add+0x1b/0xb0 [..] RIP: 0010:[] [] __list_add+0x1b/0xb0 RSP: 0018:ffffbcb3c7ba7c00 EFLAGS: 00010046 [..] Call Trace: [] insert_work+0x3a/0xc0 [] ? seq_open+0x5a/0xa0 [] __queue_work+0x16a/0x460 [] queue_work_on+0x38/0x40 [] acpi_nfit_flush_probe+0x95/0xc0 [nfit] [] ? nfit_visible+0x40/0x40 [nfit] [] wait_probe_show+0x25/0x60 [] dev_attr_show+0x20/0x50 Fixes: 7ae0fa439faf ("nfit, libnvdimm: async region scrub workqueue") Cc: Reviewed-by: Vishal Verma Signed-off-by: Dan Williams --- drivers/acpi/nfit/core.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c index 2f82b8eba360..7361d00818e2 100644 --- a/drivers/acpi/nfit/core.c +++ b/drivers/acpi/nfit/core.c @@ -2704,6 +2704,7 @@ static int acpi_nfit_flush_probe(struct nvdimm_bus_descriptor *nd_desc) struct acpi_nfit_desc *acpi_desc = to_acpi_nfit_desc(nd_desc); struct device *dev = acpi_desc->dev; struct acpi_nfit_flush_work flush; + int rc; /* bounce the device lock to flush acpi_nfit_add / acpi_nfit_notify */ device_lock(dev); @@ -2716,7 +2717,10 @@ static int acpi_nfit_flush_probe(struct nvdimm_bus_descriptor *nd_desc) INIT_WORK_ONSTACK(&flush.work, flush_probe); COMPLETION_INITIALIZER_ONSTACK(flush.cmp); queue_work(nfit_wq, &flush.work); - return wait_for_completion_interruptible(&flush.cmp); + + rc = wait_for_completion_interruptible(&flush.cmp); + cancel_work_sync(&flush.work); + return rc; } static int acpi_nfit_clear_to_send(struct nvdimm_bus_descriptor *nd_desc,