From 2a57d83c78f889bf3f54eede908d0643c40d5418 Mon Sep 17 00:00:00 2001 From: Liu Shixin Date: Fri, 24 Dec 2021 21:12:58 -0800 Subject: [PATCH] mm/hwpoison: clear MF_COUNT_INCREASED before retrying get_any_page() Hulk Robot reported a panic in put_page_testzero() when testing madvise() with MADV_SOFT_OFFLINE. The BUG() is triggered when retrying get_any_page(). This is because we keep MF_COUNT_INCREASED flag in second try but the refcnt is not increased. page dumped because: VM_BUG_ON_PAGE(page_ref_count(page) == 0) ------------[ cut here ]------------ kernel BUG at include/linux/mm.h:737! invalid opcode: 0000 [#1] PREEMPT SMP CPU: 5 PID: 2135 Comm: sshd Tainted: G B 5.16.0-rc6-dirty #373 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 RIP: release_pages+0x53f/0x840 Call Trace: free_pages_and_swap_cache+0x64/0x80 tlb_flush_mmu+0x6f/0x220 unmap_page_range+0xe6c/0x12c0 unmap_single_vma+0x90/0x170 unmap_vmas+0xc4/0x180 exit_mmap+0xde/0x3a0 mmput+0xa3/0x250 do_exit+0x564/0x1470 do_group_exit+0x3b/0x100 __do_sys_exit_group+0x13/0x20 __x64_sys_exit_group+0x16/0x20 do_syscall_64+0x34/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae Modules linked in: ---[ end trace e99579b570fe0649 ]--- RIP: 0010:release_pages+0x53f/0x840 Link: https://lkml.kernel.org/r/20211221074908.3910286-1-liushixin2@huawei.com Fixes: b94e02822deb ("mm,hwpoison: try to narrow window race for free pages") Signed-off-by: Liu Shixin Reported-by: Hulk Robot Reviewed-by: Oscar Salvador Acked-by: Naoya Horiguchi Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory-failure.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 682828b94ab60..3a274468f193e 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -2234,6 +2234,7 @@ retry: } else if (ret == 0) { if (soft_offline_free_page(page) && try_again) { try_again = false; + flags &= ~MF_COUNT_INCREASED; goto retry; } } -- 2.39.5