diff options
| author | Dan Williams <[email protected]> | 2017-02-24 14:55:45 -0800 |
|---|---|---|
| committer | Linus Torvalds <[email protected]> | 2017-02-24 17:46:53 -0800 |
| commit | b5d24fda9c3dce51fcb4eee459550a458eaaf1e2 (patch) | |
| tree | aad811ffd2581cd9d29c5995615a8b77cfe2859b | |
| parent | 299c517adb903ddd376dd103fcc9dcfff3d4728b (diff) | |
mm, devm_memremap_pages: hold device_hotplug lock over mem_hotplug_{begin, done}
The mem_hotplug_{begin,done} lock coordinates with {get,put}_online_mems()
to hold off "readers" of the current state of memory from new hotplug
actions. mem_hotplug_begin() expects exclusive access, via the
device_hotplug lock, to set mem_hotplug.active_writer. Calling
mem_hotplug_begin() without locking device_hotplug can lead to
corrupting mem_hotplug.refcount and missed wakeups / soft lockups.
[[email protected]: v2]
Link: http://lkml.kernel.org/r/148728203365.38457.17804568297887708345.stgit@dwillia2-desk3.amr.corp.intel.com
Link: http://lkml.kernel.org/r/148693885680.16345.17802627926777862337.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: f931ab479dd2 ("mm: fix devm_memremap_pages crash, use mem_hotplug_{begin, done}")
Signed-off-by: Dan Williams <[email protected]>
Reported-by: Ben Hutchings <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Toshi Kani <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Logan Gunthorpe <[email protected]>
Cc: Masayoshi Mizuma <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
| -rw-r--r-- | kernel/memremap.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/kernel/memremap.c b/kernel/memremap.c index 9ecedc28b928..06123234f118 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -246,9 +246,13 @@ static void devm_memremap_pages_release(struct device *dev, void *data) /* pages are dead and unused, undo the arch mapping */ align_start = res->start & ~(SECTION_SIZE - 1); align_size = ALIGN(resource_size(res), SECTION_SIZE); + + lock_device_hotplug(); mem_hotplug_begin(); arch_remove_memory(align_start, align_size); mem_hotplug_done(); + unlock_device_hotplug(); + untrack_pfn(NULL, PHYS_PFN(align_start), align_size); pgmap_radix_release(res); dev_WARN_ONCE(dev, pgmap->altmap && pgmap->altmap->alloc, @@ -360,9 +364,11 @@ void *devm_memremap_pages(struct device *dev, struct resource *res, if (error) goto err_pfn_remap; + lock_device_hotplug(); mem_hotplug_begin(); error = arch_add_memory(nid, align_start, align_size, true); mem_hotplug_done(); + unlock_device_hotplug(); if (error) goto err_add_memory; |