From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id ADF19181BB3; Tue, 14 May 2024 22:01:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715724118; cv=none; b=pEZckDfFc1D7Dur9CrXeRlO263Yq9iY/0iHemRfc1hBfagfJ7ZNHk2nUXmA02R4sZdCSQM8JyBeDk2I626JVmpwmPFysWNEe9zieC/qkXLdlI57Kti68X+pAt4YLvu7NHmH2Enzcm4AOqaMU/l4w2MZS/z7zpwDYO82VmNH0Kt8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715724118; c=relaxed/simple; bh=qdhxkqdLch7dDgLozqH/+44poIfKsEPpJpqcOAAZxOc=; h=Date:To:From:Subject:Message-Id; b=Z8+5U6ZxnPzkQADui9Lhv8+J99d/fnC59EPv0Vmq3Z54hXfYxh14ssqKOu648LF+WI0GxKBCZQ+K3yWPzTgPzVkjXiQCVux8+QeiCvPOLYW44XVsWL+HPKe5L7+P4PrOM0MdDqVFJN/kBunRwHngI2hsNwUXUvQhcZNDnT6G9pA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=UkTeMHS1; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="UkTeMHS1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 56A8EC32786; Tue, 14 May 2024 22:01:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1715724118; bh=qdhxkqdLch7dDgLozqH/+44poIfKsEPpJpqcOAAZxOc=; h=Date:To:From:Subject:From; b=UkTeMHS15BTRjVr2o34QCBAzxmYHhWg0Mxi+g0ciCxFZ62sMNXScMkQEwFFhAqr99 Jhcdnd+drB8hLFlOF+Wv+xHPYjfoMsd30mChhouP/arQP3vmpp3gRFQcD65aJWU8lc 8dSB8u2bUf/H1zHXF3LWvpEuz88v5sdANpmLCPjk= Date: Tue, 14 May 2024 15:01:57 -0700 To: mm-commits@vger.kernel.org,xuyu@linux.alibaba.com,willy@infradead.org,stable@vger.kernel.org,shy828301@gmail.com,nao.horiguchi@gmail.com,david@redhat.com,linmiaohe@huawei.com,akpm@linux-foundation.org From: Andrew Morton Subject: [alternative-merged] mm-huge_memory-mark-huge_zero_page-reserved.patch removed from -mm tree Message-Id: <20240514220158.56A8EC32786@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm/huge_memory: mark huge_zero_page reserved has been removed from the -mm tree. Its filename was mm-huge_memory-mark-huge_zero_page-reserved.patch This patch was dropped because an alternative patch was or shall be merged ------------------------------------------------------ From: Miaohe Lin Subject: mm/huge_memory: mark huge_zero_page reserved Date: Sat, 11 May 2024 11:54:35 +0800 When I did memory failure tests recently, below panic occurs: kernel BUG at include/linux/mm.h:1135! invalid opcode: 0000 [#1] PREEMPT SMP NOPTI CPU: 9 PID: 137 Comm: kswapd1 Not tainted 6.9.0-rc4-00491-gd5ce28f156fe-dirty #14 RIP: 0010:shrink_huge_zero_page_scan+0x168/0x1a0 RSP: 0018:ffff9933c6c57bd0 EFLAGS: 00000246 RAX: 000000000000003e RBX: 0000000000000000 RCX: ffff88f61fc5c9c8 RDX: 0000000000000000 RSI: 0000000000000027 RDI: ffff88f61fc5c9c0 RBP: ffffcd7c446b0000 R08: ffffffff9a9405f0 R09: 0000000000005492 R10: 00000000000030ea R11: ffffffff9a9405f0 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: ffff88e703c4ac00 FS: 0000000000000000(0000) GS:ffff88f61fc40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055f4da6e9878 CR3: 0000000c71048000 CR4: 00000000000006f0 Call Trace: do_shrink_slab+0x14f/0x6a0 shrink_slab+0xca/0x8c0 shrink_node+0x2d0/0x7d0 balance_pgdat+0x33a/0x720 kswapd+0x1f3/0x410 kthread+0xd5/0x100 ret_from_fork+0x2f/0x50 ret_from_fork_asm+0x1a/0x30 Modules linked in: mce_inject hwpoison_inject ---[ end trace 0000000000000000 ]--- RIP: 0010:shrink_huge_zero_page_scan+0x168/0x1a0 RSP: 0018:ffff9933c6c57bd0 EFLAGS: 00000246 RAX: 000000000000003e RBX: 0000000000000000 RCX: ffff88f61fc5c9c8 RDX: 0000000000000000 RSI: 0000000000000027 RDI: ffff88f61fc5c9c0 RBP: ffffcd7c446b0000 R08: ffffffff9a9405f0 R09: 0000000000005492 R10: 00000000000030ea R11: ffffffff9a9405f0 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: ffff88e703c4ac00 FS: 0000000000000000(0000) GS:ffff88f61fc40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055f4da6e9878 CR3: 0000000c71048000 CR4: 00000000000006f0 The root cause is that HWPoison flag will be set for huge_zero_page without increasing the page refcnt. But then unpoison_memory() will decrease the page refcnt unexpectly as it appears like a successfully hwpoisoned page leading to VM_BUG_ON_PAGE(page_ref_count(page) == 0) when releasing huge_zero_page. Fix this issue by marking huge_zero_page reserved. So unpoison_memory() will skip this page. This will make it consistent with ZERO_PAGE case too. Link: https://lkml.kernel.org/r/20240511035435.1477004-1-linmiaohe@huawei.com Fixes: 478d134e9506 ("mm/huge_memory: do not overkill when splitting huge_zero_page") Signed-off-by: Miaohe Lin Cc: Matthew Wilcox (Oracle) Cc: Naoya Horiguchi Cc: Xu Yu Cc: Yang Shi Cc: David Hildenbrand Cc: Signed-off-by: Andrew Morton --- mm/huge_memory.c | 2 ++ 1 file changed, 2 insertions(+) --- a/mm/huge_memory.c~mm-huge_memory-mark-huge_zero_page-reserved +++ a/mm/huge_memory.c @@ -212,6 +212,7 @@ retry: folio_put(zero_folio); goto retry; } + __SetPageReserved(zero_page); WRITE_ONCE(huge_zero_pfn, folio_pfn(zero_folio)); /* We take additional reference here. It will be put back by shrinker */ @@ -264,6 +265,7 @@ static unsigned long shrink_huge_zero_pa struct folio *zero_folio = xchg(&huge_zero_folio, NULL); BUG_ON(zero_folio == NULL); WRITE_ONCE(huge_zero_pfn, ~0UL); + __ClearPageReserved(zero_page); folio_put(zero_folio); return HPAGE_PMD_NR; } _ Patches currently in -mm which might be from linmiaohe@huawei.com are