diff options
| author | Dan Williams <dan.j.williams@intel.com> | 2019-08-08 23:43:49 +0200 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2019-08-09 23:16:15 +0200 |
| commit | 06282373ff57a2b82621be4f84f981e1b0a4eb28 (patch) | |
| tree | b903244b64519b1ebf6dda45f4f90c392d7a73ec | |
| parent | dax: dax_layout_busy_page() should not unmap cow pages (diff) | |
| download | linux-06282373ff57a2b82621be4f84f981e1b0a4eb28.tar.xz linux-06282373ff57a2b82621be4f84f981e1b0a4eb28.zip | |
mm/memremap: Fix reuse of pgmap instances with internal references
Currently, attempts to shutdown and re-enable a device-dax instance
trigger:
Missing reference count teardown definition
WARNING: CPU: 37 PID: 1608 at mm/memremap.c:211 devm_memremap_pages+0x234/0x850
[..]
RIP: 0010:devm_memremap_pages+0x234/0x850
[..]
Call Trace:
dev_dax_probe+0x66/0x190 [device_dax]
really_probe+0xef/0x390
driver_probe_device+0xb4/0x100
device_driver_attach+0x4f/0x60
Given that the setup path initializes pgmap->ref, arrange for it to be
also torn down so devm_memremap_pages() is ready to be called again and
not be mistaken for the 3rd-party per-cpu-ref case.
Fixes: 24917f6b1041 ("memremap: provide an optional internal refcount in struct dev_pagemap")
Reported-by: Fan Du <fan.du@intel.com>
Tested-by: Vishal Verma <vishal.l.verma@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/156530042781.2068700.8733813683117819799.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to '')
| -rw-r--r-- | mm/memremap.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/mm/memremap.c b/mm/memremap.c index 6ee03a816d67..86432650f829 100644 --- a/mm/memremap.c +++ b/mm/memremap.c @@ -91,6 +91,12 @@ static void dev_pagemap_cleanup(struct dev_pagemap *pgmap) wait_for_completion(&pgmap->done); percpu_ref_exit(pgmap->ref); } + /* + * Undo the pgmap ref assignment for the internal case as the + * caller may re-enable the same pgmap. + */ + if (pgmap->ref == &pgmap->internal_ref) + pgmap->ref = NULL; } static void devm_memremap_pages_release(void *data) |