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 5066436F8F3; Fri, 29 May 2026 04:07:03 +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=1780027626; cv=none; b=huJT5TubGrW4+v2y5bGcoKuiHPvY+4vZvRtkCpldVZeZCs4GWRluqhIJUwhnSXwqYeyEW6UbqQJ0HZ/NJfktJHFGAuWP2Fsmr1vOU1fT0wccT8fQ5LRNpa7J5G2O9Dg+OVuk8N7FZhHWvMLbC5U110w7uIv7KwPp1q5aWHo4gDU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780027626; c=relaxed/simple; bh=Vm/5ZY9yBnUCt0p+ejFLJg5wN425Gc4KYXYyU8ShOTI=; h=Date:To:From:Subject:Message-Id; b=GMezJOI+1+abxsVHvhJ7pHYWCf3JCQVlt6wmz0tbSQdVqWR+xoSxEaEIribhPvw6eF59G3cNTFgsQuUu6dIh4YGwRgTj48rD35gg3kOuV2O9oe/i9onpgk3bDx9He4J2328tuD3I8TLoY0ZK4HX1YzMcaRA1u9LznspcjrmUQR4= 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=K91Q9EI4; 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="K91Q9EI4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 246D81F00893; Fri, 29 May 2026 04:07:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1780027623; bh=WvAva1x8+ftDyxYKlJo6Nf6lqDHfd5B57x5w6jkTaTU=; h=Date:To:From:Subject; b=K91Q9EI4fgWKmJuNHcPf9doc9Kh11pKzjNJSsreovPxVp5TljR74NhCnQm0x6DTWn g+WvAfqIA6Is76+6Vwjj+x6ta+4OUAXKswJ/XbEQLGHAbUiPSpnWVzFWGGrrOZqq79 v/2aEruflBimFH3GZtaczG1YFEwSnwLbAxamG0ps= Date: Thu, 28 May 2026 21:07:02 -0700 To: mm-commits@vger.kernel.org,stable@vger.kernel.org,osalvador@suse.de,muchun.song@linux.dev,david@kernel.org,almasrymina@google.com,kartikey406@gmail.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] mm-hugetlb-fix-hugetlb-cgroup-rsvd-charge-uncharge-mismatch.patch removed from -mm tree Message-Id: <20260529040703.246D81F00893@smtp.kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm/hugetlb: fix hugetlb cgroup rsvd charge/uncharge mismatch has been removed from the -mm tree. Its filename was mm-hugetlb-fix-hugetlb-cgroup-rsvd-charge-uncharge-mismatch.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Deepanshu Kartikey Subject: mm/hugetlb: fix hugetlb cgroup rsvd charge/uncharge mismatch Date: Sat, 28 Mar 2026 12:25:34 +0530 In alloc_hugetlb_folio(), a single h_cg pointer is used for both the rsvd and non-rsvd hugetlb cgroup charges. When map_chg is set, hugetlb_cgroup_charge_cgroup_rsvd() stores the charged cgroup in h_cg, but the immediately following hugetlb_cgroup_charge_cgroup() overwrites h_cg with the non-rsvd cgroup pointer. As a result, hugetlb_cgroup_commit_charge_rsvd() stores the wrong (non-rsvd) cgroup pointer into the folio's rsvd slot. When the folio is later freed, free_huge_folio() unconditionally calls both hugetlb_cgroup_uncharge_folio() and hugetlb_cgroup_uncharge_folio_rsvd(). The rsvd uncharge reads back the wrong cgroup from the folio and decrements a counter that was never charged for that cgroup, causing a page_counter underflow: page_counter underflow: -512 nr_pages=512 WARNING: mm/page_counter.c:61 at page_counter_cancel Fix this by introducing a separate h_cg_rsvd pointer exclusively for the rsvd charge path, keeping the rsvd and non-rsvd charges fully independent through their charge, commit, and error uncharge paths. Link: https://lore.kernel.org/20260328065534.346053-1-kartikey406@gmail.com Fixes: 08cf9faf7558 ("hugetlb_cgroup: support noreserve mappings") Reported-by: syzbot+226c1f947186f8fef796@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=226c1f947186f8fef796 Signed-off-by: Deepanshu Kartikey Reviewed-by: Muchun Song Cc: David Hildenbrand Cc: Oscar Salvador Cc: Mina Almasry Cc: Signed-off-by: Andrew Morton --- mm/hugetlb.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) --- a/mm/hugetlb.c~mm-hugetlb-fix-hugetlb-cgroup-rsvd-charge-uncharge-mismatch +++ a/mm/hugetlb.c @@ -2859,6 +2859,7 @@ struct folio *alloc_hugetlb_folio(struct map_chg_state map_chg; int ret, idx; struct hugetlb_cgroup *h_cg = NULL; + struct hugetlb_cgroup *h_cg_rsvd = NULL; gfp_t gfp = htlb_alloc_mask(h) | __GFP_RETRY_MAYFAIL; idx = hstate_index(h); @@ -2909,7 +2910,7 @@ struct folio *alloc_hugetlb_folio(struct */ if (map_chg) { ret = hugetlb_cgroup_charge_cgroup_rsvd( - idx, pages_per_huge_page(h), &h_cg); + idx, pages_per_huge_page(h), &h_cg_rsvd); if (ret) goto out_subpool_put; } @@ -2951,7 +2952,7 @@ struct folio *alloc_hugetlb_folio(struct */ if (map_chg) { hugetlb_cgroup_commit_charge_rsvd(idx, pages_per_huge_page(h), - h_cg, folio); + h_cg_rsvd, folio); } spin_unlock_irq(&hugetlb_lock); @@ -3003,7 +3004,7 @@ out_uncharge_cgroup: out_uncharge_cgroup_reservation: if (map_chg) hugetlb_cgroup_uncharge_cgroup_rsvd(idx, pages_per_huge_page(h), - h_cg); + h_cg_rsvd); out_subpool_put: /* * put page to subpool iff the quota of subpool's rsv_hpages is used _ Patches currently in -mm which might be from kartikey406@gmail.com are