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Hyper-V memory hotplug protocol has 2M granularity and in Linux x86 we use 128M. To deal with it we implement partial section onlining by registering custom page onlining callback (hv_online_page()). Later, when more memory arrives we try to online the 'tail' (see hv_bring_pgs_online()). It was found that in some cases this 'tail' onlining causes issues: BUG: Bad page state in process kworker/0:2 pfn:109e3a page:ffffe08344278e80 count:0 mapcount:1 mapping:0000000000000000 index:0x0 flags: 0xfffff80000000() raw: 000fffff80000000 dead000000000100 dead000000000200 0000000000000000 raw: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 page dumped because: nonzero mapcount ... Workqueue: events hot_add_req [hv_balloon] Call Trace: dump_stack+0x5c/0x80 bad_page.cold.112+0x7f/0xb2 free_pcppages_bulk+0x4b8/0x690 free_unref_page+0x54/0x70 hv_page_online_one+0x5c/0x80 [hv_balloon] hot_add_req.cold.24+0x182/0x835 [hv_balloon] ... Turns out that we now have deferred struct page initialization for memory hotplug so e.g. memory_block_action() in drivers/base/memory.c does pages_correctly_probed() check and in that check it avoids inspecting struct pages and checks sections instead. But in Hyper-V balloon driver we do PageReserved(pfn_to_page()) check and this is now wrong. Switch to checking online_section_nr() instead. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: stable@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org> |
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| .. | ||
| channel_mgmt.c | ||
| channel.c | ||
| connection.c | ||
| hv_balloon.c | ||
| hv_fcopy.c | ||
| hv_kvp.c | ||
| hv_snapshot.c | ||
| hv_trace_balloon.h | ||
| hv_trace.c | ||
| hv_trace.h | ||
| hv_util.c | ||
| hv_utils_transport.c | ||
| hv_utils_transport.h | ||
| hv.c | ||
| hyperv_vmbus.h | ||
| Kconfig | ||
| Makefile | ||
| ring_buffer.c | ||
| vmbus_drv.c | ||