From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-188.mta1.migadu.com (out-188.mta1.migadu.com [95.215.58.188]) (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 C290D8BE0 for ; Fri, 22 Mar 2024 03:24:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.188 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711077899; cv=none; b=iBack1afHNiWOveuxgpqNll6Dufxuld7VwCX8u9BxQ6+e35WqS/Q9eQRZL6xkEyiu3RouNyWiu/wI0Z0KsgRxQRgvRSTF+yaoBOZsKb8SY+vEq/x0evJYLphbF5SJM/XSuyVpCqEU+HgVrR+TkNjhZDnewQkgn6CEDwvV3v/rvc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711077899; c=relaxed/simple; bh=9XPjD+HP21f4zddlLmex6fWKZNAEjxzYlyxyr/LxtsQ=; h=Content-Type:Mime-Version:Subject:From:In-Reply-To:Date:Cc: Message-Id:References:To; b=cM6YJsM4Vr/oSj1m6URO/RQJ/8p7saflBG469tRf68oBin0Q2H7p5OOk1TiGoK86Ttmbk3Ei16U/ImGLBCvy+LiADqWuCEfwUc4Umag65iR97xIOJUtiJh6+0zYGhrrazqzCzV12m+yThsCGqZMvTZDUpp2u/vAZ6O1p6zoy1d8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=UVJ+CcqO; arc=none smtp.client-ip=95.215.58.188 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) header.d=linux.dev header.i=@linux.dev header.b="UVJ+CcqO" Content-Type: text/plain; charset=us-ascii DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1711077894; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9XPjD+HP21f4zddlLmex6fWKZNAEjxzYlyxyr/LxtsQ=; b=UVJ+CcqORFfUVHdqZRyiE8nwhY51TtQGbRVq27cC7AtHLcN2BtsZkcd8Wj15Eni/xVSpn/ Ptaw19McrVffmH9YvE67dyFLMe4B8su+FODJYCUsqLYyT4UB0jyY5mfLMJP/E53NL1UbsW jOn93oXrVO8Vw5KqTRsQG2GX8StVyiA= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Subject: Re: [syzbot] [mm?] kernel BUG in const_folio_flags X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Muchun Song In-Reply-To: Date: Fri, 22 Mar 2024 11:24:10 +0800 Cc: syzbot , David Hildenbrand , Matthew Wilcox , Andrew Morton , LKML , Linux-MM , syzkaller-bugs@googlegroups.com Content-Transfer-Encoding: quoted-printable Message-Id: <1349A15A-341F-4EE4-AD40-805A97A9FFD1@linux.dev> References: <0000000000006cfe98061423cde7@google.com> <812E97E8-668F-414D-9480-1D284834A034@linux.dev> To: Oscar Salvador X-Migadu-Flow: FLOW_OUT > On Mar 21, 2024, at 18:20, Oscar Salvador wrote: >=20 > On Thu, Mar 21, 2024 at 05:49:49PM +0800, Muchun Song wrote: >> There are some more page dumping information from console: >>=20 >> [ 61.367144][ T42] page: refcount:0 mapcount:0 = mapping:0000000000000000 index:0xffff888028132880 pfn:0x28130 >> [ 61.371430][ T42] flags: = 0xfff80000000000(node=3D0|zone=3D1|lastcpupid=3D0xfff) >> [ 61.374455][ T42] page_type: 0xffffffff() >> [ 61.376096][ T42] raw: 00fff80000000000 ffff888015ecd540 = dead000000000100 0000000000000000 >> [ 61.379994][ T42] raw: ffff888028132880 0000000000190000 = 00000000ffffffff 0000000000000000 >>=20 >> Alright, the page is freed (with a refcount of 0). >=20 > Yes, basically the page changed betwen folio_test_large() (returned = true > for PG_Head) and the call to const_folio_flags() (which now returned > false for PG_Head). >=20 > As David pointed out, Willy is working on making PageHutelb more > robust [1]. >=20 >=20 > [1] = https://lore.kernel.org/linux-mm/20240314012506.1600378-1-willy@infradead.= org/ Sorry, I am not on the CC list, so I didn't know this. But thank you and David for this information, I think it could fix this problem. Muchun, Thanks.