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 E3BFB37474C for ; Mon, 23 Feb 2026 20:12:16 +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=1771877537; cv=none; b=B8du/RgWapW3FF49CmIt1aKm0QWV2rmeEzrMCq87dC2a4WHQ+hc8zu4nI2Ul6M3VPljH2a0Xe2C6lIbasqKm1WeAru9t1+cm3BeEZexkput49QSb0eJVVVTRZt4Qqqz9beVHtk6dDfBLgN3Z7SygyWBwSv8V+aOWZhSLNt4NXBE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771877537; c=relaxed/simple; bh=03jUB21huD9WXALJGJv0bSZYCb+998/0dA32FF25SE0=; h=Date:To:From:Subject:Message-Id; b=Nk/ZxZ4nLn/4vA0HgrRyO4M/BN/2x0SLTMDECJx34GosawVODCziJubH6U9ZAo5ogFa1GjfUuOzhIGx/THFR3FFPKILKB34Gpq5MJCaSdB9lCzsrQZC55g/QmJKRtX6JeKTubAx+6fBr0zo7qWZy12k+LZUF7i7isEDrC475SHg= 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=ILIhgFN2; 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="ILIhgFN2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 63AE7C19421; Mon, 23 Feb 2026 20:12:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1771877536; bh=03jUB21huD9WXALJGJv0bSZYCb+998/0dA32FF25SE0=; h=Date:To:From:Subject:From; b=ILIhgFN2xXXA9QZ5uTQ7EnfFgahdsPnRuoEdIY6GnxxMONTI2cM+7kxAZxUskJqCn 3AIfBjqGXDJB0G77D15DJx22mMuF0p2W8FO5YmBpM1+29sqCKcJxQEGtICED4gh+GA 0A4qx6CGgHOWKObej9wbhF+mo4yGeQpZ7c0cRNMA= Date: Mon, 23 Feb 2026 12:12:15 -0800 To: mm-commits@vger.kernel.org,vbabka@kernel.org,surenb@google.com,rppt@kernel.org,riel@surriel.com,mhocko@suse.com,lorenzo.stoakes@oracle.com,Liam.Howlett@oracle.com,jannh@google.com,harry.yoo@oracle.com,david@kernel.org,akpm@linux-foundation.org,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-centralizefix-comments-about-compound_mapcount-in-new-sync_with_folio_pmd_zap-fix.patch added to mm-unstable branch Message-Id: <20260223201216.63AE7C19421@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm-centralizefix-comments-about-compound_mapcount-in-new-sync_with_folio_pmd_zap-fix has been added to the -mm mm-unstable branch. Its filename is mm-centralizefix-comments-about-compound_mapcount-in-new-sync_with_folio_pmd_zap-fix.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-centralizefix-comments-about-compound_mapcount-in-new-sync_with_folio_pmd_zap-fix.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Andrew Morton Subject: mm-centralizefix-comments-about-compound_mapcount-in-new-sync_with_folio_pmd_zap-fix Date: Mon Feb 23 12:09:18 PM PST 2026 update comment per Matthew and David Cc: "David Hildenbrand (Arm)" Cc: Harry Yoo Cc: Jann Horn Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Rik van Riel Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- mm/internal.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/mm/internal.h~mm-centralizefix-comments-about-compound_mapcount-in-new-sync_with_folio_pmd_zap-fix +++ a/mm/internal.h @@ -521,10 +521,10 @@ void pmd_install(struct mm_struct *mm, p * @mm: The mm_struct. * @pmdp: Pointer to the pmd that was found to be pmd_none(). * - * When we stumble over a pmd_none() without holding the PTL while unmapping a - * folio that could have been mapped at that PMD, it could be that concurrent - * zapping of the PMD is not complete yet. While the PMD might be pmd_none() - * already, the folio might still appear to be mapped (folio_mapped()). + * When we find a pmd_none() while unmapping a folio without holding the PTL, + * zap_huge_pmd() may have cleared the PMD but not yet modified the folio to + * indicate that it's unmapped. Skipping the PMD without synchronization could + * make folio unmapping code assume that unmapping failed. * * Wait for concurrent zapping to complete by grabbing the PTL. */ _ Patches currently in -mm which might be from akpm@linux-foundation.org are maple_tree-start-using-maple-copy-node-for-destination-checkpatch-fixes.patch maple_tree-add-cp_is_new_root-helper-fix-fix.patch lib-introduce-hierarchical-per-cpu-counters-fix.patch mm-centralizefix-comments-about-compound_mapcount-in-new-sync_with_folio_pmd_zap-fix.patch kernel-panic-increase-buffer-size-for-verbose-taint-logging-fix.patch