I saw the following BUG_ON triggered in a testcase where a process calls
madvise(MADV_SOFT_OFFLINE) on thps, along with a background process that
calls migratepages command repeatedly (doing ping-pong among different
NUMA nodes) for the first process:
[ 52.556731] Soft offlining page 0x60000 at 0x700000600000
[ 52.592620] __get_any_page: 0x60000 free buddy page
[ 52.593451] page:ffffea0001800000 count:0 mapcount:-127 mapping: (null) index:0x1
[ 52.594767] flags: 0x1fffc0000000000()
[ 52.595402] page dumped because: VM_BUG_ON_PAGE(atomic_read(&page->_count) == 0)
[ 52.596602] ------------[ cut here ]------------
[ 52.597339] kernel BUG at /src/linux-dev/include/linux/mm.h:342!
[ 52.598284] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC
[ 52.599193] Modules linked in: cfg80211 rfkill crc32c_intel serio_raw virtio_balloon i2c_piix4 virtio_blk virtio_net ata_generic pata_acpi
[ 52.600579] CPU: 3 PID: 3035 Comm: test_alloc_gene Tainted: G O 4.4.0-rc8-v4.4-rc8-160107-1501-00000-rc8+ #74
[ 52.600579] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 52.600579] task: ffff88007c63d5c0 ti: ffff88007c210000 task.ti: ffff88007c210000
[ 52.600579] RIP: 0010:[<ffffffff8118998c>] [<ffffffff8118998c>] put_page+0x5c/0x60
[ 52.600579] RSP: 0018:ffff88007c213e00 EFLAGS: 00010246
[ 52.600579] RAX: 0000000000000044 RBX: ffffea0001800000 RCX: 0000000000000000
[ 52.600579] RDX: ffff88011f50f570 RSI: 0000000000000000 RDI: ffff88011f50cc18
[ 52.600579] RBP: ffff88007c213e08 R08: 000000000000000a R09: 000000000000149c
[ 52.600579] R10: ffff8800dac927f8 R11: 000000000000149c R12: ffffea0001800000
[ 52.600579] R13: 0000000000060000 R14: ffffea0001800000 R15: 0000000000000065
[ 52.600579] FS: 00007feb79d7d740(0000) GS:ffff88011f500000(0000) knlGS:0000000000000000
[ 52.600579] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 52.600579] CR2: 00007f3032cd2000 CR3: 00000000da6c4000 CR4: 00000000000006e0
[ 52.600579] Stack:
[ 52.600579] ffffea0001800000 ffff88007c213e28 ffffffff811eb2ee ffffea0001800000
[ 52.600579] 00000000fffffffb ffff88007c213e70 ffffffff811eccd1 0000000000000018
[ 52.600579] ffff88007c213e50 0000700000600000 0000700000601000 0000160000000000
[ 52.600579] Call Trace:
[ 52.600579] [<ffffffff811eb2ee>] put_hwpoison_page+0x4e/0x80
[ 52.600579] [<ffffffff811eccd1>] soft_offline_page+0x501/0x520
[ 52.600579] [<ffffffff811bd18c>] SyS_madvise+0x6bc/0x6f0
[ 52.600579] [<ffffffff8104d0ac>] ? fpu__restore_sig+0xcc/0x320
[ 52.600579] [<ffffffff810a0003>] ? do_sigaction+0x73/0x1b0
[ 52.600579] [<ffffffff8109ceb2>] ? __set_task_blocked+0x32/0x70
[ 52.600579] [<ffffffff81652757>] entry_SYSCALL_64_fastpath+0x12/0x6a
[ 52.600579] Code: 8b fc ff ff 5b 5d c3 48 89 df e8 b0 fa ff ff 48 89 df 31 f6 e8 c6 7d ff ff 5b 5d c3 48 c7 c6 08 54 a2 81 48 89 df e8 a4 c5 01 00 <0f> 0b 66 90 66 66 66 66 90 55 48 89 e5 41 55 41 54 53 48 8b 47
[ 52.600579] RIP [<ffffffff8118998c>] put_page+0x5c/0x60
[ 52.600579] RSP <ffff88007c213e00>
The root cause resides in get_any_page() which retries to get a refcount of
the page to be soft-offlined. This function calls put_hwpoison_page(), expecting
that the target page is putback to LRU list. But it can be also freed to buddy.
So the second check need to care about such case.
Fixes: af8fae7c0886 ("mm/memory-failure.c: clean up soft_offline_page()")
Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v3.9+
---
mm/memory-failure.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git v4.4-rc8/mm/memory-failure.c v4.4-rc8_patched/mm/memory-failure.c
index 8424b64..750b789 100644
--- v4.4-rc8/mm/memory-failure.c
+++ v4.4-rc8_patched/mm/memory-failure.c
@@ -1572,7 +1572,7 @@ static int get_any_page(struct page *page, unsigned long pfn, int flags)
* Did it turn free?
*/
ret = __get_any_page(page, pfn, 0);
- if (!PageLRU(page)) {
+ if (ret == 1 && !PageLRU(page)) {
/* Drop page reference which is from __get_any_page() */
put_hwpoison_page(page);
pr_info("soft_offline: %#lx: unknown non LRU page type %lx\n",
--
1.7.1
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