From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 88EB1381AFF for ; Wed, 9 Sep 2026 06:54:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788936870; cv=none; b=jH4RE28zx482Hsx2tGSFSiP8sMSMn147outSR6ejMh9ChA81Tv1VHw8/vx7I3KVE50VGbIxP8DJZAi1feZrqHg+Nupz6L0yYa5e9mdTLJhowBhjag+D5h9ql3PJi292IzrH8fKVk3UJR2d25tt/dFbMmPtftXq1er2QzJd5mw4U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788936870; c=relaxed/simple; bh=W5vMRO/wEoE7oAwzvwC2HVWRuaH7B6korbDmGYKAMFE=; h=Date:To:From:Subject:Message-Id; b=TKDJ/92N3pSWu0Ek6X3sKQjTgRFk/EZUAq0lYSzy44V6ZKeUpryBb2Qbhyj1oiNaxh2yp+p7b9K/c+ohl2QaKFlLESgatdXlZr9+mXs/fxRTejIKjqKAGtS807PaV9wfcifopD6exS2Df3ouBNY+NOW3/DwqMe1QHG/d0bkJgd8= 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=lYGotZ2m; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="lYGotZ2m" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4E0761F00A3D; Wed, 9 Sep 2026 06:54:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1788936869; bh=xXe1HTBVBkTC2WV+qkK5ErR8n5YwiKFNSMt/df2sYXM=; h=Date:To:From:Subject; b=lYGotZ2mjF93b2yL5p+sDhi6G0n29b305OiVqyXdQGIHQZYPMtAsE3o2DHVAHIrH5 8yvN8lFyisf3Ay3JFAvreQe1st5Q4ggoGbZKtKy+2/8AFU/FDKZQhCk5cnqQ8yoyNV 9tjo1iBsWpWfHBdbFEybg3DXNBN63ik5/EoryQcQ= Date: Tue, 08 Sep 2026 23:54:28 -0700 To: mm-commits@vger.kernel.org,yanglincheng@kylinos.cn,akpm@linux-foundation.org From: Andrew Morton Subject: [to-be-updated] mm-khugepaged-fix-folio-is-used-after-folio_put-unlock.patch removed from -mm tree Message-Id: <20260909065429.4E0761F00A3D@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: khugepaged: fix folio is used after folio_put/unlock() has been removed from the -mm tree. Its filename was mm-khugepaged-fix-folio-is-used-after-folio_put-unlock.patch This patch was dropped because an updated version will be issued ------------------------------------------------------ From: Vernon Yang Subject: mm: khugepaged: fix folio is used after folio_put/unlock() Date: Fri, 28 Aug 2026 13:59:26 +0800 On the rollback path, folio_put() has already dropped the last reference of new_folio. On the success path, new_folio is already unlocked and can be freed concurrently. The trace_mm_khugepaged_collapse_file() is left with a dangling folio pointer. So using the folio_pfn() before dropping the reference, closing use-after-free window. Link: https://lore.kernel.org/20260828055926.346744-4-vernon2gm@gmail.com Fixes: 4c9473e87e75 ("mm/khugepaged: add tracepoint to collapse_file()") Signed-off-by: Vernon Yang Acked-by: Lorenzo Stoakes (ARM) Cc: Barry Song Cc: David Hildenbrand Cc: Dev Jain Cc: Lance Yang Cc: Ryan Roberts Cc: Zach O'Keefe Cc: Signed-off-by: Andrew Morton --- include/trace/events/huge_memory.h | 6 +++--- mm/khugepaged.c | 4 +++- 2 files changed, 6 insertions(+), 4 deletions(-) --- a/include/trace/events/huge_memory.h~mm-khugepaged-fix-folio-is-used-after-folio_put-unlock +++ a/include/trace/events/huge_memory.h @@ -211,10 +211,10 @@ TRACE_EVENT(mm_khugepaged_scan_file, ); TRACE_EVENT(mm_khugepaged_collapse_file, - TP_PROTO(struct mm_struct *mm, struct folio *new_folio, pgoff_t index, + TP_PROTO(struct mm_struct *mm, unsigned long new_pfn, pgoff_t index, unsigned long addr, bool is_shmem, struct file *file, int nr, int result), - TP_ARGS(mm, new_folio, index, addr, is_shmem, file, nr, result), + TP_ARGS(mm, new_pfn, index, addr, is_shmem, file, nr, result), TP_STRUCT__entry( __field(struct mm_struct *, mm) __field(unsigned long, hpfn) @@ -228,7 +228,7 @@ TRACE_EVENT(mm_khugepaged_collapse_file, TP_fast_assign( __entry->mm = mm; - __entry->hpfn = new_folio ? folio_pfn(new_folio) : -1; + __entry->hpfn = new_pfn; __entry->index = index; __entry->addr = addr; __entry->is_shmem = is_shmem; --- a/mm/khugepaged.c~mm-khugepaged-fix-folio-is-used-after-folio_put-unlock +++ a/mm/khugepaged.c @@ -2256,6 +2256,7 @@ static enum scan_result collapse_file(st struct address_space *mapping = file->f_mapping; struct page *dst; struct folio *folio, *tmp, *new_folio; + unsigned long new_pfn = -1; pgoff_t index = 0, end = start + HPAGE_PMD_NR; LIST_HEAD(pagelist); XA_STATE_ORDER(xas, &mapping->i_pages, start, HPAGE_PMD_ORDER); @@ -2275,6 +2276,7 @@ static enum scan_result collapse_file(st result = alloc_charge_folio(&new_folio, mm, cc, HPAGE_PMD_ORDER); if (result != SCAN_SUCCEED) goto out; + new_pfn = folio_pfn(new_folio); mapping_set_update(&xas, mapping); @@ -2678,7 +2680,7 @@ rollback: folio_put(new_folio); out: VM_BUG_ON(!list_empty(&pagelist)); - trace_mm_khugepaged_collapse_file(mm, new_folio, index, addr, is_shmem, file, HPAGE_PMD_NR, result); + trace_mm_khugepaged_collapse_file(mm, new_pfn, index, addr, is_shmem, file, HPAGE_PMD_NR, result); return result; } _ Patches currently in -mm which might be from yanglincheng@kylinos.cn are x86-mm-fix-pmd_modify-dropping-the-dirty-bit.patch