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Subject: Re: [RFC PATCH v9 00/13] Add support for eXclusive Page Frame
 Ownership
From:   Nadav Amit <nadav.amit@gmail.com>
In-Reply-To: <cover.1554248001.git.khalid.aziz@oracle.com>
Date:   Thu, 4 Apr 2019 09:44:43 -0700
Cc:     X86 ML <x86@kernel.org>, linux-arm-kernel@lists.infradead.org,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
        Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
        Linux-MM <linux-mm@kvack.org>,
        LSM List <linux-security-module@vger.kernel.org>
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Message-Id: <3F95B70B-7910-4150-A9D3-05C4D0195B67@gmail.com>
References: <cover.1554248001.git.khalid.aziz@oracle.com>
To:     Khalid Aziz <khalid.aziz@oracle.com>
Sender: linux-kernel-owner@vger.kernel.org
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> On Apr 3, 2019, at 10:34 AM, Khalid Aziz <khalid.aziz@oracle.com> =
wrote:
>=20
> This is another update to the work Juerg, Tycho and Julian have
> done on XPFO.

Interesting work, but note that it triggers a warning on my system due =
to
possible deadlock. It seems that the patch-set disables IRQs in
xpfo_kunmap() and then might flush remote TLBs when a large page is =
split.
This is wrong, since it might lead to deadlocks.


[  947.262208] WARNING: CPU: 6 PID: 9892 at kernel/smp.c:416 =
smp_call_function_many+0x92/0x250
[  947.263767] Modules linked in: sb_edac vmw_balloon crct10dif_pclmul =
crc32_pclmul joydev ghash_clmulni_intel input_leds intel_rapl_perf =
serio_raw mac_hid sch_fq_codel ib_iser rdma_cm iw_cm ib_cm ib_core =
vmw_vsock_vmci_transport vsock vmw_vmci iscsi_tcp libiscsi_tcp libiscsi =
scsi_transport_iscsi ip_tables x_tables autofs4 btrfs zstd_compress =
raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor =
async_tx libcrc32c xor raid6_pq raid1 raid0 multipath linear hid_generic =
usbhid hid vmwgfx drm_kms_helper syscopyarea sysfillrect sysimgblt =
fb_sys_fops ttm drm aesni_intel psmouse aes_x86_64 crypto_simd cryptd =
glue_helper mptspi vmxnet3 scsi_transport_spi mptscsih ahci mptbase =
libahci i2c_piix4 pata_acpi
[  947.274649] CPU: 6 PID: 9892 Comm: cc1 Not tainted 5.0.0+ #7
[  947.275804] Hardware name: VMware, Inc. VMware Virtual Platform/440BX =
Desktop Reference Platform, BIOS 6.00 07/28/2017
[  947.277704] RIP: 0010:smp_call_function_many+0x92/0x250
[  947.278640] Code: 3b 05 66 fc 4e 01 72 26 48 83 c4 10 5b 41 5c 41 5d =
41 5e 41 5f 5d c3 8b 05 2b cc 7e 01 85 c0 75 bf 80 3d a8 99 4e 01 00 75 =
b6 <0f> 0b eb b2 44 89 c7 48 c7 c2 a0 9a 61 aa 4c 89 fe 44 89 45 d0 e8
[  947.281895] RSP: 0000:ffffafe04538f970 EFLAGS: 00010046
[  947.282821] RAX: 0000000000000000 RBX: 0000000000000006 RCX: =
0000000000000001
[  947.284084] RDX: 0000000000000000 RSI: ffffffffa9078d70 RDI: =
ffffffffaa619aa0
[  947.285343] RBP: ffffafe04538f9a8 R08: ffff9d7040000ff0 R09: =
0000000000000000
[  947.286596] R10: 0000000000000000 R11: 0000000000000000 R12: =
ffffffffa9078d70
[  947.287855] R13: 0000000000000000 R14: 0000000000000001 R15: =
ffffffffaa619aa0
[  947.289118] FS:  00007f668b122ac0(0000) GS:ffff9d727fd80000(0000) =
knlGS:0000000000000000
[  947.290550] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  947.291569] CR2: 00007f6688389004 CR3: 0000000224496006 CR4: =
00000000003606e0
[  947.292861] DR0: 0000000000000000 DR1: 0000000000000000 DR2: =
0000000000000000
[  947.294125] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: =
0000000000000400
[  947.295394] Call Trace:
[  947.295854]  ? load_new_mm_cr3+0xe0/0xe0
[  947.296568]  on_each_cpu+0x2d/0x60
[  947.297191]  flush_tlb_all+0x1c/0x20
[  947.297846]  __split_large_page+0x5d9/0x640
[  947.298604]  set_kpte+0xfe/0x260
[  947.299824]  get_page_from_freelist+0x1633/0x1680
[  947.301260]  ? lookup_address+0x2d/0x30
[  947.302550]  ? set_kpte+0x1e1/0x260
[  947.303760]  __alloc_pages_nodemask+0x13f/0x2e0
[  947.305137]  alloc_pages_vma+0x7a/0x1c0
[  947.306378]  wp_page_copy+0x201/0xa30
[  947.307582]  ? generic_file_read_iter+0x96a/0xcf0
[  947.308946]  do_wp_page+0x1cc/0x420
[  947.310086]  __handle_mm_fault+0xc0d/0x1600
[  947.311331]  handle_mm_fault+0xe1/0x210
[  947.312502]  __do_page_fault+0x23a/0x4c0
[  947.313672]  ? _cond_resched+0x19/0x30
[  947.314795]  do_page_fault+0x2e/0xe0
[  947.315878]  ? page_fault+0x8/0x30
[  947.316916]  page_fault+0x1e/0x30
[  947.317930] RIP: 0033:0x76581e
[  947.318893] Code: eb 05 89 d8 48 8d 04 80 48 8d 34 c5 08 00 00 00 48 =
85 ff 74 04 44 8b 67 04 e8 de 80 08 00 81 e3 ff ff ff 7f 48 89 45 00 8b =
10 <44> 89 60 04 81 e2 00 00 00 80 09 da 89 10 c1 ea 18 83 e2 7f 88 50
[  947.323337] RSP: 002b:00007ffde06c0e40 EFLAGS: 00010202
[  947.324663] RAX: 00007f6688389000 RBX: 0000000000000004 RCX: =
0000000000000001
[  947.326317] RDX: 0000000000000000 RSI: 0000000001000001 RDI: =
0000000000000017
[  947.327973] RBP: 00007f66883882d8 R08: 00000000032e05f0 R09: =
00007f668b30e6f0
[  947.329619] R10: 0000000000000002 R11: 00000000032e05f0 R12: =
0000000000000000
[  947.331260] R13: 00007f6688388230 R14: 00007f6688388288 R15: =
00007f668ac3b0a8
[  947.332911] ---[ end trace 7d605a38c67d83ae ]---=