From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794356633; b=B/8GmQmBmDDf/AbFMrLUzuJKhNWe665jwWFiHLw4wCzj0CCzYC3NSVk31A6Gdjx6w2MV K0bPNHXjCii+S1U593hsBvYu8ofUgCHRKjSH+ShnglHABKgPnvIXGL/dUxCmlCbuOUEnQ XOys3877doaUyYsu2kLPHCbzW7qjN+HtF7n/OrXfUOhZ16WzVP9a9PhVDugzZsPrye2S7 ZAdb07hwxh7IjewogWwrYWPe1pHn1PdfuV2vyyhmHXihoM2st+M8ug/Qf0kS8cuxYrtXQ Fg6N39Dr7RT+Qar20iOoaT63vhPotnw7+CR9eg8gANBx6FXLPinZv229wvP5r+5zHIA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794356633; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=/jqsQx//57Km+wTcF4mtArZYDImIFskYwPOlHgb7KLA=; b=0zPLSzwaITaIPgAVpvg81qt7Exk5ipUPw5obaFKs/q+VT7wG0yfh5q6fc0hWNPFpRgbF fut92iSESiKLRZtKwxIFryQvJGMJaZsIJ0AnWsHQT5In0UxHlPSzgsI+f+2n0BBINxuC2 a+LymMAVO/XRbyStO1tv8egzIS0I8Zwq1cBwXimDTXKICYioavD8N9eH9XsYFNSWGrBJ7 Bu8XS0tDncB3ZwA3SWYEVHwye8/L/f4XHjLoc7CK/Ix8tmfTUIh7uo4Ubm6IZ5ENpBhjV bTXtRI5I8p/TZlrUKEAK588F1d4chSdB2+jV7PpPx/OCUU0aNiSnv8YqfGqs1PCx57g== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=EWumpYEe; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 11B29606A31C for ; Wed, 11 Nov 2026 00:23:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=EWumpYEe Received: by smtp.kernel.org (Postfix) with ESMTPSA id D1AF21F0089F; Wed, 11 Nov 2026 00:23:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794356632; bh=/jqsQx//57Km+wTcF4mtArZYDImIFskYwPOlHgb7KLA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=EWumpYEek6V15ldiKDd4mM9mtkkSRfM1SW3lku9VhpAMSouG5S283lYZZfF0ohRFK zAI72E0R7+5oQ4C/ZHS/f8wenxSmp9SRdunxv2csN1sP0IoW9SkyNgC0rnJLXMqH9D e7KP6RSr6bRseDGXV47TT6EHQOSxkThl15Ai7LjOJvATmx+plXt7WSgcKHsSjqxtPh 42dnKgG6ZisJk0QQGbppScnmMPPBaTMOaRaOByTwDPX/f7xW5rkxT0e4Kw9lhXk1sT yx5uggZL0IUMqWClkPOvckas+UiXJ6IKjbd+NS3F/J8mPTEa9clKV/pF8BU2L5gCxa +9MsWDVCt8pLA== From: Sasha Levin To: stable@vger.kernel.org Cc: Ackerley Tng , Andrew Morton , Muchun Song , Joshua Hahn , Alex Shi , David Hildenbrand , David Rientjes , Dongliang Mu , Frank van der Linden , Hongxiang Lou , James Houghton , Johannes Weiner , Jonathan Corbet , "Liam R. Howlett" , Lorenzo Stoakes , Ma Wupeng , Miaohe Lin , Michal Hocko , Mike Rapoport , Nhat Pham , Oscar Salvador , Peter Xu , Roman Gushchin , Shakeel Butt , Suren Baghdasaryan , Vishal Annapurve , Vlastimil Babka , Yanteng Si , Sasha Levin Subject: [PATCH 6.18.y] mm: hugetlb: return -ENOSPC on memcg charge failure Date: Tue, 10 Nov 2026 19:23:48 -0500 Message-ID: <20261111002224.251188-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261107050856-failed-6.18-956aeff185e7@kernel.org> References: <20261107050856-failed-6.18-956aeff185e7@kernel.org> X-Mailing-List: stable@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: Ackerley Tng [ Upstream commit 956aeff185e7e16b989202bde0bb29859adba99d ] Patch series "Fix bugs in HugeTLB allocation when mem_cgroup_charge_hugetlb() fails", v2. In hugetlb_alloc_folio(), when mem_cgroup_charge_hugetlb() fails, there are 2 issues: 1. free_huge_folio() expects a non-refcounted folio and will VM_BUG_ON_FOLIO(). 2. -ENOMEM is returned, causing an infinite loop retrying the fault. This patch (of 2): When mem_cgroup_charge_hugetlb() fails with -ENOMEM, alloc_hugetlb_folio() currently propagates this error. This results in the page fault handler returning VM_FAULT_OOM. Because HugeTLB allocations are high-order and use __GFP_RETRY_MAYFAIL, they bypass the OOM killer. Returning VM_FAULT_OOM to the #PF handler without triggering the OOM killer (or having it make progress) leads to an infinite loop of retrying the fault. Avoid this loop by returning -ENOSPC when charging fails, which maps to VM_FAULT_SIGBUS, terminating the process cleanly. Make mem_cgroup_charge_hugetlb() fault handling use a common error handling path, the same handling used for hugetlb_cgroup_uncharge_cgroup{,_rsvd}(), which also don't trigger the OOM killer and hence opt to terminate the process with a SIGBUS. Link: https://lore.kernel.org/20260909-hugetlb-alloc-folio-memcg-charge-error-handling-v2-1-4b4a8a19a7f7@google.com Fixes: 991135774c0e ("memcg/hugetlb: introduce mem_cgroup_charge_hugetlb") Signed-off-by: Ackerley Tng Signed-off-by: Andrew Morton Reviewed-by: Muchun Song Reviewed-by: Joshua Hahn Cc: Alex Shi Cc: David Hildenbrand Cc: David Rientjes Cc: Dongliang Mu Cc: Frank van der Linden Cc: Hongxiang Lou Cc: James Houghton Cc: Johannes Weiner Cc: Jonathan Corbet Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Ma Wupeng Cc: Miaohe Lin Cc: Michal Hocko Cc: Mike Rapoport Cc: Nhat Pham Cc: Oscar Salvador Cc: Peter Xu Cc: Roman Gushchin Cc: Shakeel Butt Cc: Suren Baghdasaryan Cc: Vishal Annapurve Cc: Vlastimil Babka Cc: Yanteng Si Cc: [ sashal: Adapted the change to alloc_hugetlb_folio() because hugetlb_alloc_folio() has not been extracted. ] Signed-off-by: Sasha Levin --- mm/hugetlb.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index bf1188e9b1c9b..2a79a3663bbc9 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -3134,7 +3134,11 @@ struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma, if (ret == -ENOMEM) { free_huge_folio(folio); - return ERR_PTR(-ENOMEM); + /* + * Return -ENOSPC, since retrying the fault is futile: + * the OOM killer is not triggered for HugeTLB. + */ + return ERR_PTR(-ENOSPC); } return folio; -- 2.53.0