4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Dan Williams <dan.j.williams@xxxxxxxxx>
commit e471486c13b82b1338d49c798f78bb62b1ed0a9e upstream.
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: [<ffffffffa9413a7b>] __list_add+0x1b/0xb0
[..]
RIP: 0010:[<ffffffffa9413a7b>] [<ffffffffa9413a7b>] __list_add+0x1b/0xb0
RSP: 0018:ffffbcb3c7ba7c00 EFLAGS: 00010046
[..]
Call Trace:
[<ffffffffa90bb11a>] insert_work+0x3a/0xc0
[<ffffffffa927fdda>] ? seq_open+0x5a/0xa0
[<ffffffffa90bb30a>] __queue_work+0x16a/0x460
[<ffffffffa90bbb08>] queue_work_on+0x38/0x40
[<ffffffffc0cf2685>] acpi_nfit_flush_probe+0x95/0xc0 [nfit]
[<ffffffffc0cf25d0>] ? nfit_visible+0x40/0x40 [nfit]
[<ffffffffa9571495>] wait_probe_show+0x25/0x60
[<ffffffffa9546b30>] dev_attr_show+0x20/0x50
Fixes: 7ae0fa439faf ("nfit, libnvdimm: async region scrub workqueue")
Reviewed-by: Vishal Verma <vishal.l.verma@xxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/acpi/nfit/core.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -2704,6 +2704,7 @@ static int acpi_nfit_flush_probe(struct
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
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,
--
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