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Fri, 12 Apr 2019 15:18:50 +0000 Received: from BYAPR05MB4776.namprd05.prod.outlook.com ([fe80::4140:b8f2:8e3:f5fd]) by BYAPR05MB4776.namprd05.prod.outlook.com ([fe80::4140:b8f2:8e3:f5fd%4]) with mapi id 15.20.1792.009; Fri, 12 Apr 2019 15:18:50 +0000 From: Nadav Amit To: Nadav Amit CC: Peter Zijlstra , kernel test robot , LKP , Linux List Kernel Mailing , Linux-MM , linux-arch , Ingo Molnar , Thomas Gleixner , Will Deacon , Andy Lutomirski , Linus Torvalds , Dave Hansen Subject: Re: 1808d65b55 ("asm-generic/tlb: Remove arch_tlb*_mmu()"): BUG: KASAN: stack-out-of-bounds in __change_page_attr_set_clr Thread-Topic: 1808d65b55 ("asm-generic/tlb: Remove arch_tlb*_mmu()"): BUG: KASAN: stack-out-of-bounds in __change_page_attr_set_clr Thread-Index: AQHU8R5sUhi0mJ9uO0aA/EiVew3tvaY4YIQAgABBN4CAAAIWgA== Date: Fri, 12 Apr 2019 15:18:50 +0000 Message-ID: References: <5cae03c4.iIPk2cWlfmzP0Zgy%lkp@intel.com> <20190411193906.GA12232@hirez.programming.kicks-ass.net> <20190411195424.GL14281@hirez.programming.kicks-ass.net> <20190411211348.GA8451@worktop.programming.kicks-ass.net> <20190412105633.GM14281@hirez.programming.kicks-ass.net> <20190412111756.GO14281@hirez.programming.kicks-ass.net> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: spf=none (sender IP is ) smtp.mailfrom=namit@vmware.com; x-originating-ip: [66.170.99.2] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 5193581f-08bc-4945-8a0e-08d6bf5a2b06 x-microsoft-antispam: BCL:0;PCL:0;RULEID:(2390118)(7020095)(4652040)(8989299)(4534185)(4627221)(201703031133081)(201702281549075)(8990200)(5600139)(711020)(4605104)(2017052603328)(7193020);SRVR:BYAPR05MB5958; x-ms-traffictypediagnostic: BYAPR05MB5958: x-ms-exchange-purlcount: 1 x-microsoft-antispam-prvs: x-forefront-prvs: 0005B05917 x-forefront-antispam-report: SFV:NSPM;SFS:(10009020)(366004)(346002)(396003)(39860400002)(136003)(376002)(189003)(199004)(105586002)(81166006)(6246003)(7416002)(186003)(25786009)(6862004)(11346002)(36756003)(486006)(446003)(8936002)(6306002)(5660300002)(99286004)(68736007)(6512007)(4326008)(305945005)(93886005)(2616005)(7736002)(6436002)(6506007)(33656002)(6486002)(66066001)(14444005)(76176011)(476003)(53546011)(256004)(3846002)(26005)(71200400001)(14454004)(71190400001)(966005)(8676002)(6116002)(6200100001)(106356001)(102836004)(86362001)(53936002)(478600001)(97736004)(83716004)(316002)(54906003)(82746002)(37006003)(2906002)(4001150100001)(81156014)(229853002)(561944003)(45080400002)(41533002);DIR:OUT;SFP:1101;SCL:1;SRVR:BYAPR05MB5958;H:BYAPR05MB4776.namprd05.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;MX:1;A:1; received-spf: None (protection.outlook.com: vmware.com does not designate permitted sender hosts) x-ms-exchange-senderadcheck: 1 x-microsoft-antispam-message-info: 6+S7ezK5Pq7/7I+FrfwbGofBilVuFuxLikmoZiik24LtJACMvNKADFK0HJPg7uaRaaelG5AqblywggA3M8v+UX4jOHyql3ph5gmi+c03dMWE0All5/46OTMxznREyvmB5DsA1RfYOI1+yS8Bm3FO0k3Fmdx3jxQCs2ECNeNLA/LsidpNoQzUW2+jgpDIryMtkSdBBcvxVyP22wszHvM9m4EuAeznZiqZIZtT20MpDwhr10BoRdmWVvaxW7I5EM24WESmaKCkAWJTrQ6l60mgaIKR9N+oVKtyheev9VAlbdCmu7UNm+erixzLyeNeUQKh0SEM0Bby381+d9F8ofc0hNDWiueBG5oWUXrJoVwxzs6V+a/Xxby+yDF/GRtARMpV/vhwRDa4AHu5/n4Ere0lUARSrjQntmBKzMPM0VxbRz8= Content-Type: text/plain; charset="us-ascii" Content-ID: <4D374FA26FC0D54A8F36E822321AB309@namprd05.prod.outlook.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: vmware.com X-MS-Exchange-CrossTenant-Network-Message-Id: 5193581f-08bc-4945-8a0e-08d6bf5a2b06 X-MS-Exchange-CrossTenant-originalarrivaltime: 12 Apr 2019 15:18:50.3720 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: b39138ca-3cee-4b4a-a4d6-cd83d9dd62f0 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR05MB5958 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: > On Apr 12, 2019, at 8:11 AM, Nadav Amit wrote: >=20 >> On Apr 12, 2019, at 4:17 AM, Peter Zijlstra wrote= : >>=20 >> On Fri, Apr 12, 2019 at 12:56:33PM +0200, Peter Zijlstra wrote: >>> On Thu, Apr 11, 2019 at 11:13:48PM +0200, Peter Zijlstra wrote: >>>> On Thu, Apr 11, 2019 at 09:54:24PM +0200, Peter Zijlstra wrote: >>>>> On Thu, Apr 11, 2019 at 09:39:06PM +0200, Peter Zijlstra wrote: >>>>>> I think this bisect is bad. If you look at your own logs this patch >>>>>> merely changes the failure, but doesn't make it go away. >>>>>>=20 >>>>>> Before this patch (in fact, before tip/core/mm entirely) the errror >>>>>> reads like the below, which suggests there is memory corruption >>>>>> somewhere, and the fingered patch just makes it trigger differently. >>>>>>=20 >>>>>> It would be very good to find the source of this corruption, but I'm >>>>>> fairly certain it is not here. >>>>>=20 >>>>> I went back to v4.20 to try and find a time when the below error did = not >>>>> occur, but even that reliably triggers the warning. >>>>=20 >>>> So I also tested v4.19 and found that that was good, which made me >>>> bisect v4.19..v4.20 >>>>=20 >>>> # bad: [8fe28cb58bcb235034b64cbbb7550a8a43fd88be] Linux 4.20 >>>> # good: [84df9525b0c27f3ebc2ebb1864fa62a97fdedb7d] Linux 4.19 >>>> git bisect start 'v4.20' 'v4.19' >>>> # bad: [ec9c166434595382be3babf266febf876327774d] Merge tag 'mips_fixe= s_4.20_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux >>>> git bisect bad ec9c166434595382be3babf266febf876327774d >>>> # bad: [50b825d7e87f4cff7070df6eb26390152bb29537] Merge git://git.kern= el.org/pub/scm/linux/kernel/git/davem/net-next >>>> git bisect bad 50b825d7e87f4cff7070df6eb26390152bb29537 >>>> # good: [99e9acd85ccbdc8f5785f9e961d4956e96bd6aa5] Merge tag 'mlx5-upd= ates-2018-10-17' of git://git.kernel.org/pub/scm/linux/kernel/git/saeed/lin= ux >>>> git bisect good 99e9acd85ccbdc8f5785f9e961d4956e96bd6aa5 >>>> # good: [c403993a41d50db1e7d9bc2d43c3c8498162312f] Merge tag 'for-linu= s-4.20' of https://nam04.safelinks.protection.outlook.com/?url=3Dhttps%3A%2= F%2Fgithub.com%2Fcminyard%2Flinux-ipmi&data=3D02%7C01%7Cnamit%40vmware.= com%7Ca1c3ea5d4bc34cfc785508d6bf388ff3%7Cb39138ca3cee4b4aa4d6cd83d9dd62f0%7= C0%7C0%7C636906647013777573&sdata=3D3VSR3VdE5rxOitAdkqFNPpAnAtLgDmYLzJt= oUrs5v9Y%3D&reserved=3D0 >>>> git bisect good c403993a41d50db1e7d9bc2d43c3c8498162312f >>>> # good: [c05f3642f4304dd081876e77a68555b6aba4483f] Merge branch 'perf-= core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip >>>> git bisect good c05f3642f4304dd081876e77a68555b6aba4483f >>>> # bad: [44786880df196a4200c178945c4d41675faf9fb7] Merge branch 'parisc= -4.20-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-lin= ux >>>> git bisect bad 44786880df196a4200c178945c4d41675faf9fb7 >>>> # bad: [99792e0cea1ed733cdc8d0758677981e0cbebfed] Merge branch 'x86-mm= -for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip >>>> git bisect bad 99792e0cea1ed733cdc8d0758677981e0cbebfed >>>> # good: [fec98069fb72fb656304a3e52265e0c2fc9adf87] Merge branch 'x86-c= pu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip >>>> git bisect good fec98069fb72fb656304a3e52265e0c2fc9adf87 >>>> # bad: [a31acd3ee8f7dbc0370bdf4a4bfef7a8c13c7542] x86/mm: Page size aw= are flush_tlb_mm_range() >>>> git bisect bad a31acd3ee8f7dbc0370bdf4a4bfef7a8c13c7542 >>>> # good: [a7295fd53c39ce781a9792c9dd2c8747bf274160] x86/mm/cpa: Use flu= sh_tlb_kernel_range() >>>> git bisect good a7295fd53c39ce781a9792c9dd2c8747bf274160 >>>> # good: [9cf38d5559e813cccdba8b44c82cc46ba48d0896] kexec: Allocate dec= rypted control pages for kdump if SME is enabled >>>> git bisect good 9cf38d5559e813cccdba8b44c82cc46ba48d0896 >>>> # good: [5b12904065798fee8b153a506ac7b72d5ebbe26c] x86/mm/doc: Clean u= p the x86-64 virtual memory layout descriptions >>>> git bisect good 5b12904065798fee8b153a506ac7b72d5ebbe26c >>>> # good: [cf089611f4c446285046fcd426d90c18f37d2905] proc/vmcore: Fix i3= 86 build error of missing copy_oldmem_page_encrypted() >>>> git bisect good cf089611f4c446285046fcd426d90c18f37d2905 >>>> # good: [a5b966ae42a70b194b03eaa5eaea70d8b3790c40] Merge branch 'tlb/a= sm-generic' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux in= to x86/mm >>>> git bisect good a5b966ae42a70b194b03eaa5eaea70d8b3790c40 >>>> # first bad commit: [a31acd3ee8f7dbc0370bdf4a4bfef7a8c13c7542] x86/mm:= Page size aware flush_tlb_mm_range() >>>>=20 >>>> And 'funnily' the bad patch is one of mine too :/ >>>>=20 >>>> I'll go have a look at that tomorrow, because currrently I'm way past >>>> tired. >>>=20 >>> OK, so the below patchlet makes it all good. It turns out that the >>> provided config has: >>>=20 >>> CONFIG_X86_L1_CACHE_SHIFT=3D7 >>>=20 >>> which then, for some obscure raisin, results in flush_tlb_mm_range() >>> compiling to use 320 bytes of stack: >>>=20 >>> sub $0x140,%rsp >>>=20 >>> Where a 'defconfig' build results in: >>>=20 >>> sub $0x58,%rsp >>>=20 >>> The thing that pushes it over the edge in the above fingered patch is >>> the addition of a field to struct flush_tlb_info, which grows if from 3= 2 >>> to 36 bytes. >>>=20 >>> So my proposal is to basically revert that, unless we can come up with >>> something that GCC can't screw up. >>=20 >> To clarify, 'that' is Nadav's patch: >>=20 >> 515ab7c41306 ("x86/mm: Align TLB invalidation info") >>=20 >> which turns out to be the real problem. >=20 > Sorry for that. I still think it should be aligned, especially with all t= he > effort the Intel puts around to avoid bus-locking on unaligned atomic > operations. >=20 > So the right solution seems to me as putting this data structure off stac= k. > It would prevent flush_tlb_mm_range() from being reentrant, so we can kee= p a > few entries for this matter and atomically increase the entry number ever= y > time we enter flush_tlb_mm_range(). >=20 > But my question is - should flush_tlb_mm_range() be reentrant, or can we > assume no TLB shootdowns are initiated in interrupt handlers and #MC > handlers? Just to clarify - I obviously suggest a per-cpu structure. The question is about one core reentering flush_tlb_mm_range().