From: Liu Shixin liushixin2@huawei.com

mainline inclusion from linux-v5.16-rc7 commit 2a57d83c78f889bf3f54eede908d0643c40d5418 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I4LE22 CVE: NA

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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 liushixin2@huawei.com Reported-by: Hulk Robot hulkci@huawei.com Reviewed-by: Oscar Salvador osalvador@suse.de Acked-by: Naoya Horiguchi naoya.horiguchi@nec.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Ma Wupeng mawupeng1@huawei.com Reviewed-by: Kefeng Wang wangkefeng.wang@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- mm/memory-failure.c | 1 + 1 file changed, 1 insertion(+)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 578859c94866f..c743ad409908c 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1955,6 +1955,7 @@ int soft_offline_page(struct page *page, int flags) else if (ret == 0) if (soft_offline_free_page(page) && try_again) { try_again = false; + flags &= ~MF_COUNT_INCREASED; goto retry; }