From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=91.218.175.49 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793587795; b=F0ZJ2LprDvtxFPzjJdhLjMnndWs+3qlbvEeCH7jLQkR9w6iSEqWpyjgGk4EnKhCghwdm +y2h6QPAx0u9axjtOh2/NyTyXF5G6lFGjFKnlBCazktyhE5y2NcWJ/9RPxD86oXUUvL9J ZSQtUuS0X5ZRuuwscHpPwHAKFNAXVDm9uoKTlUAPv10OApk2z/D5soGsOxjCygTTQZBho 6sz6fqFsC8tn4cNpSNtK+lQBhbjQkU3N7gAmkpyC6sNBpdNFN3wthsYsTHbHzuFCu+YJk gcPzRUT2GOCCQaz0oLvHVFU1aQRYx3IVpcJB0SPPR8zH74qhl3+47zj8nPxuyF8jKTg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793587795; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:From:To:Cc:Subject:Date:Message-ID: X-Mailer:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=wsq265Y6LzBmkOdoymoFNHjnl3IW2ovvlI+9AwjjAuE=; b=YiPUThusFUsIF7iltLL2nODK2c/paNdmhx7w7+tYoZ4Ts1iEdwNoXlOOXZxN1qSLdI5o 0R18SO159qWXkqOqO48fahV95NCTDpZREu+/sM49qgrjslemqx1LZeOjNZwhnscc+ByV7 YNwkCzmvvV8Vb5XEpAKposzG6FAvHd0Lf5FFlRKVuwmadnBOBIoy6ctPGt8mpM1qapjRV 8/5loqxGyfKhBsKZdU52nXUlAELvQ2g09Q5hzhC93NDlkA86rzeMUi8yx5twk5H2NHO7x Nzp59qabnPzuqGqy6iwPmGfO+W6mZrdv6D+idc+at2tccFzniHJyCA2WUsBz/s2xzwQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b="EKPM/T/+"; arc=none smtp.remote-ip=91.218.175.49 Received: from mta0.migadu.com (out-49.mta0.migadu.com [91.218.175.49]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 392F7606A326 for ; Mon, 2 Nov 2026 02:49:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 392F7606A326 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=EKPM/T/+ X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=j8pQESwrLrfT9Kc/KC2iuBXUJfIeLEImyATEFj6zlDg=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1793587791; v=1; x=1794192591; b=EKPM/T/+fyZPfUGce3JQha20CDV8IN2FPRNcOmK0DL8riFkgbS58yOw2GC1oidgq5ierEgkF XcvtGSINu4IDEsSUidFOVkOQFjDSmAHdqQUuVt7TXSNCvnhcc9Jm6Ji7ZfAodvxAmmRvBH6KPOp BfOCPH3lpOtabQbt5d7mmxSk= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 348b45477b4b0c16; Mon, 02 Nov 2026 02:49:51 +0000 X-Mizu-Trace-ID: 348b45477b4b0c16 X-Migadu-Flow: FLOW_OUT From: Kaitao Cheng To: Muchun Song , Oscar Salvador , David Hildenbrand , Andrew Morton , Mike Rapoport , Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt Cc: Mani Tofigh , Zi Yan , Mike Kravetz , Baolin Wang , Miaohe Lin , Naoya Horiguchi , Frank van der Linden , Chris Down , Joshua Hahn , linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Kaitao Cheng Subject: [PATCH v2 2/3] mm/hugetlb: Preserve persistent flags when returning folios to the pool Date: Mon, 2 Nov 2026 10:49:09 +0800 Message-ID: <20261102024910.31486-3-kaitao.cheng@linux.dev> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20261102024910.31486-1-kaitao.cheng@linux.dev> References: <20261102024910.31486-1-kaitao.cheng@linux.dev> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Kaitao Cheng add_hugetlb_folio() returns a folio to the HugeTLB pool when vmemmap restoration fails. It clears folio->private and restores only HPG_vmemmap_optimized, losing other flags that must survive the rollback. Clearing HPG_cma causes a later free to bypass the CMA release path, leaving the CMA allocation bitmap set. Clearing HPG_raw_hwp_unreliable loses the indication that the locations of poisoned subpages are unknown, undermining the checks that prevent freeing or unpoisoning such folios. Preserve the existing flags instead of resetting folio->private. Callers already clear HPG_restore_reserve, HPG_migratable and HPG_freed before returning a folio to the pool. Clear HPG_temporary in free_huge_folio() before attempting to free a temporary folio, so a failed vmemmap restore does not leave that flag set on a folio returned as surplus. Add a VM_WARN_ON_ONCE_FOLIO() check for flags other than HPG_vmemmap_optimized, HPG_raw_hwp_unreliable and HPG_cma to detect incomplete transient flag cleanup. Fixes: 161df60e9e89 ("mm, hwpoison, hugetlb: support saving mechanism of raw error pages") Fixes: d2d786714080 ("mm/hugetlb: enable bootmem allocation from CMA areas") Closes: https://sashiko.dev/#/bug/linux-5363eb09-9c3c-4f8b-9f3c-a998a8c4b258 Suggested-by: David Hildenbrand Suggested-by: Muchun Song Suggested-by: Zi Yan Signed-off-by: Kaitao Cheng --- mm/hugetlb.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 4a008afaedf9..931ca3a30773 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1443,6 +1443,12 @@ void add_hugetlb_folio(struct hstate *h, struct folio *folio, lockdep_assert_held(&hugetlb_lock); + /* Callers must clear transient flags before returning to the pool. */ + VM_WARN_ON_ONCE_FOLIO((unsigned long)folio->private & + ~(BIT(HPG_vmemmap_optimized) | + BIT(HPG_raw_hwp_unreliable) | + BIT(HPG_cma)), folio); + INIT_LIST_HEAD(&folio->lru); h->nr_huge_pages++; h->nr_huge_pages_node[nid]++; @@ -1453,9 +1459,6 @@ void add_hugetlb_folio(struct hstate *h, struct folio *folio, } __folio_set_hugetlb(folio); - /* Clear all folio->private flags except hugetlb_vmemmap_optimized. */ - folio->private = NULL; - folio_set_hugetlb_vmemmap_optimized(folio); arch_clear_hugetlb_flags(folio); enqueue_hugetlb_folio(h, folio); @@ -1743,6 +1746,7 @@ void free_huge_folio(struct folio *folio) h->resv_huge_pages++; if (folio_test_hugetlb_temporary(folio)) { + folio_clear_hugetlb_temporary(folio); remove_hugetlb_folio(h, folio, false); spin_unlock_irqrestore(&hugetlb_lock, flags); update_and_free_hugetlb_folio(h, folio, true); -- 2.54.0 (Apple Git-157)