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DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1657772701; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=QFGu2TWdKctYd3jzQb7mcIpilK5qcQQipmt2wnr4Teg=; b=X5Y7ADJtRLRlG8Hoy8Xid5t/PtUaUJdq5UHQ5PPCu3LL68/j93w3CesxPKtcqAnywdK5Kq k1xfExT3M7VNgAXkK/Grlf2AO78LpJJKq2lw6VIFfaRoP0wz3y1/s0rJJXXbV6usFO8rAu zK7P5ELEEt7xmWa6st/unT9NT5CpW8I= From: Naoya Horiguchi To: linux-mm@kvack.org Cc: Andrew Morton , David Hildenbrand , Mike Kravetz , Miaohe Lin , Liu Shixin , Yang Shi , Oscar Salvador , Muchun Song , Naoya Horiguchi , linux-kernel@vger.kernel.org Subject: [mm-unstable PATCH v7 7/8] mm, hwpoison: skip raw hwpoison page in freeing 1GB hugepage Date: Thu, 14 Jul 2022 13:24:19 +0900 Message-Id: <20220714042420.1847125-8-naoya.horiguchi@linux.dev> In-Reply-To: <20220714042420.1847125-1-naoya.horiguchi@linux.dev> References: <20220714042420.1847125-1-naoya.horiguchi@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev ARC-Authentication-Results: i=1; imf12.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=X5Y7ADJt; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf12.hostedemail.com: domain of naoya.horiguchi@linux.dev designates 188.165.223.204 as permitted sender) smtp.mailfrom=naoya.horiguchi@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1657772703; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=QFGu2TWdKctYd3jzQb7mcIpilK5qcQQipmt2wnr4Teg=; b=il44Q8RUhk0HmnTmPrXePOMoSig9vpco9MS8nkIjSpqHHzXzf7wY1bwd7cc27JEQcfy6AS 0q3behbvfhRuATralJ60dSdZ1huccaau2OppyRwcTtu6E490zSHinygO0Il5UYZ72Ua/cH xMadM+FiybDi28OcTD5WiH4O6gWaY/s= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1657772703; a=rsa-sha256; cv=none; b=h1BNAst/f4TKmT+zUqBkEmjSzrsRZkd0MnRnH0RN0dOxEd8fRSFTFrM6WOxA68mH4YAPUi 29OJqrxh6f58SZeKO3+wY4xfun5T+NzpXq3Kxu1ejsMZpPazhEA1zHH/+hfFIKxnE0+cXi NF2Qp9q4q+sirD3leAVtg5m+qX5Xq9s= X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: F2D9A40075 X-Stat-Signature: eh8shsbf9tninpjthsjnh9654ygnu1ex Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=X5Y7ADJt; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf12.hostedemail.com: domain of naoya.horiguchi@linux.dev designates 188.165.223.204 as permitted sender) smtp.mailfrom=naoya.horiguchi@linux.dev X-Rspam-User: X-HE-Tag: 1657772702-197589 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Naoya Horiguchi Currently if memory_failure() (modified to remove blocking code with subsequent patch) is called on a page in some 1GB hugepage, memory error handling fails and the raw error page gets into leaked state. The impact is small in production systems (just leaked single 4kB page), but this limits the testability because unpoison doesn't work for it. We can no longer create 1GB hugepage on the 1GB physical address range with such leaked pages, that's not useful when testing on small systems. When a hwpoison page in a 1GB hugepage is handled, it's caught by the PageHWPoison check in free_pages_prepare() because the 1GB hugepage is broken down into raw error pages before coming to this point: if (unlikely(PageHWPoison(page)) && !order) { ... return false; } Then, the page is not sent to buddy and the page refcount is left 0. Originally this check is supposed to work when the error page is freed from page_handle_poison() (that is called from soft-offline), but now we are opening another path to call it, so the callers of __page_handle_poison() need to handle the case by considering the return value 0 as success. Then page refcount for hwpoison is properly incremented so unpoison works. Signed-off-by: Naoya Horiguchi Reviewed-by: Miaohe Lin --- v2 -> v3: - remove "res = MF_FAILED" in try_memory_failure_hugetlb (by Miaohe) --- mm/memory-failure.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index c8fa3643791c..3721de624b98 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1084,7 +1084,6 @@ static int me_huge_page(struct page_state *ps, struct page *p) res = truncate_error_page(hpage, page_to_pfn(p), mapping); unlock_page(hpage); } else { - res = MF_FAILED; unlock_page(hpage); /* * migration entry prevents later access on error hugepage, @@ -1092,9 +1091,11 @@ static int me_huge_page(struct page_state *ps, struct page *p) * subpages. */ put_page(hpage); - if (__page_handle_poison(p) > 0) { + if (__page_handle_poison(p) >= 0) { page_ref_inc(p); res = MF_RECOVERED; + } else { + res = MF_FAILED; } } @@ -1874,10 +1875,11 @@ static int try_memory_failure_hugetlb(unsigned long pfn, int flags, int *hugetlb */ if (res == 0) { unlock_page(head); - res = MF_FAILED; - if (__page_handle_poison(p) > 0) { + if (__page_handle_poison(p) >= 0) { page_ref_inc(p); res = MF_RECOVERED; + } else { + res = MF_FAILED; } action_result(pfn, MF_MSG_FREE_HUGE, res); return res == MF_RECOVERED ? 0 : -EBUSY; -- 2.25.1