--- /dev/null
+From stable+bounces-179574-greg=kroah.com@vger.kernel.org Sun Sep 14 15:30:50 2025
+From: Sasha Levin <sashal@kernel.org>
+Date: Sun, 14 Sep 2025 09:30:42 -0400
+Subject: mm/memory-failure: fix VM_BUG_ON_PAGE(PagePoisoned(page)) when unpoison memory
+To: stable@vger.kernel.org
+Cc: Miaohe Lin <linmiaohe@huawei.com>, David Hildenbrand <david@redhat.com>, Naoya Horiguchi <nao.horiguchi@gmail.com>, Andrew Morton <akpm@linux-foundation.org>, Sasha Levin <sashal@kernel.org>
+Message-ID: <20250914133042.87228-1-sashal@kernel.org>
+
+From: Miaohe Lin <linmiaohe@huawei.com>
+
+[ Upstream commit d613f53c83ec47089c4e25859d5e8e0359f6f8da ]
+
+When I did memory failure tests, below panic occurs:
+
+page dumped because: VM_BUG_ON_PAGE(PagePoisoned(page))
+kernel BUG at include/linux/page-flags.h:616!
+Oops: invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
+CPU: 3 PID: 720 Comm: bash Not tainted 6.10.0-rc1-00195-g148743902568 #40
+RIP: 0010:unpoison_memory+0x2f3/0x590
+RSP: 0018:ffffa57fc8787d60 EFLAGS: 00000246
+RAX: 0000000000000037 RBX: 0000000000000009 RCX: ffff9be25fcdc9c8
+RDX: 0000000000000000 RSI: 0000000000000027 RDI: ffff9be25fcdc9c0
+RBP: 0000000000300000 R08: ffffffffb4956f88 R09: 0000000000009ffb
+R10: 0000000000000284 R11: ffffffffb4926fa0 R12: ffffe6b00c000000
+R13: ffff9bdb453dfd00 R14: 0000000000000000 R15: fffffffffffffffe
+FS: 00007f08f04e4740(0000) GS:ffff9be25fcc0000(0000) knlGS:0000000000000000
+CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
+CR2: 0000564787a30410 CR3: 000000010d4e2000 CR4: 00000000000006f0
+Call Trace:
+ <TASK>
+ unpoison_memory+0x2f3/0x590
+ simple_attr_write_xsigned.constprop.0.isra.0+0xb3/0x110
+ debugfs_attr_write+0x42/0x60
+ full_proxy_write+0x5b/0x80
+ vfs_write+0xd5/0x540
+ ksys_write+0x64/0xe0
+ do_syscall_64+0xb9/0x1d0
+ entry_SYSCALL_64_after_hwframe+0x77/0x7f
+RIP: 0033:0x7f08f0314887
+RSP: 002b:00007ffece710078 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
+RAX: ffffffffffffffda RBX: 0000000000000009 RCX: 00007f08f0314887
+RDX: 0000000000000009 RSI: 0000564787a30410 RDI: 0000000000000001
+RBP: 0000564787a30410 R08: 000000000000fefe R09: 000000007fffffff
+R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000009
+R13: 00007f08f041b780 R14: 00007f08f0417600 R15: 00007f08f0416a00
+ </TASK>
+Modules linked in: hwpoison_inject
+---[ end trace 0000000000000000 ]---
+RIP: 0010:unpoison_memory+0x2f3/0x590
+RSP: 0018:ffffa57fc8787d60 EFLAGS: 00000246
+RAX: 0000000000000037 RBX: 0000000000000009 RCX: ffff9be25fcdc9c8
+RDX: 0000000000000000 RSI: 0000000000000027 RDI: ffff9be25fcdc9c0
+RBP: 0000000000300000 R08: ffffffffb4956f88 R09: 0000000000009ffb
+R10: 0000000000000284 R11: ffffffffb4926fa0 R12: ffffe6b00c000000
+R13: ffff9bdb453dfd00 R14: 0000000000000000 R15: fffffffffffffffe
+FS: 00007f08f04e4740(0000) GS:ffff9be25fcc0000(0000) knlGS:0000000000000000
+CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
+CR2: 0000564787a30410 CR3: 000000010d4e2000 CR4: 00000000000006f0
+Kernel panic - not syncing: Fatal exception
+Kernel Offset: 0x31c00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
+---[ end Kernel panic - not syncing: Fatal exception ]---
+
+The root cause is that unpoison_memory() tries to check the PG_HWPoison
+flags of an uninitialized page. So VM_BUG_ON_PAGE(PagePoisoned(page)) is
+triggered. This can be reproduced by below steps:
+
+1.Offline memory block:
+
+ echo offline > /sys/devices/system/memory/memory12/state
+
+2.Get offlined memory pfn:
+
+ page-types -b n -rlN
+
+3.Write pfn to unpoison-pfn
+
+ echo <pfn> > /sys/kernel/debug/hwpoison/unpoison-pfn
+
+This scenario can be identified by pfn_to_online_page() returning NULL.
+And ZONE_DEVICE pages are never expected, so we can simply fail if
+pfn_to_online_page() == NULL to fix the bug.
+
+Link: https://lkml.kernel.org/r/20250828024618.1744895-1-linmiaohe@huawei.com
+Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online")
+Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
+Suggested-by: David Hildenbrand <david@redhat.com>
+Acked-by: David Hildenbrand <david@redhat.com>
+Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
+Cc: <stable@vger.kernel.org>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+[ Adjust context ]
+Signed-off-by: Sasha Levin <sashal@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ mm/memory-failure.c | 7 +++----
+ 1 file changed, 3 insertions(+), 4 deletions(-)
+
+--- a/mm/memory-failure.c
++++ b/mm/memory-failure.c
+@@ -1543,10 +1543,9 @@ int unpoison_memory(unsigned long pfn)
+ static DEFINE_RATELIMIT_STATE(unpoison_rs, DEFAULT_RATELIMIT_INTERVAL,
+ DEFAULT_RATELIMIT_BURST);
+
+- if (!pfn_valid(pfn))
+- return -ENXIO;
+-
+- p = pfn_to_page(pfn);
++ p = pfn_to_online_page(pfn);
++ if (!p)
++ return -EIO;
+ page = compound_head(p);
+
+ if (!PageHWPoison(p)) {