Re: [PATCH 0/2] fix devm_memremap_pages() mem hotplug locking

2017-02-14 Thread Masayoshi Mizuma
On Sun, 12 Feb 2017 17:35:00 -0800 Dan Williams wrote: > On Sun, Feb 12, 2017 at 5:25 PM, Masayoshi Mizuma > wrote: > > Hi Dan, > > > > On Sun, 12 Feb 2017 14:34:11 -0800 Dan Williams wrote: > >> > >> Ben notes that commit f931ab479dd2 "mm: fix devm_memremap_pages crash, > >> use mem_hotplug_{be

Re: [PATCH 0/2] fix devm_memremap_pages() mem hotplug locking

2017-02-12 Thread Masayoshi Mizuma
Hi Dan, On Sun, 12 Feb 2017 14:34:11 -0800 Dan Williams wrote: Ben notes that commit f931ab479dd2 "mm: fix devm_memremap_pages crash, use mem_hotplug_{begin, done}" is incomplete and broken. Writes to mem_hotplug.active_writer need to be coordinated under the device hotplug lock. Otherwise, we c

Re: [PATCH 0/2] fix devm_memremap_pages() mem hotplug locking

2017-02-12 Thread Dan Williams
On Sun, Feb 12, 2017 at 5:25 PM, Masayoshi Mizuma wrote: > Hi Dan, > > On Sun, 12 Feb 2017 14:34:11 -0800 Dan Williams wrote: >> >> Ben notes that commit f931ab479dd2 "mm: fix devm_memremap_pages crash, >> use mem_hotplug_{begin, done}" is incomplete and broken. Writes to >> mem_hotplug.active_wri

[PATCH 0/2] fix devm_memremap_pages() mem hotplug locking

2017-02-12 Thread Dan Williams
Ben notes that commit f931ab479dd2 "mm: fix devm_memremap_pages crash, use mem_hotplug_{begin, done}" is incomplete and broken. Writes to mem_hotplug.active_writer need to be coordinated under the device hotplug lock. Otherwise, we can potentially corrupt mem_hotplug.refcount leading to soft lockup