From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx143.postini.com [74.125.245.143]) by kanga.kvack.org (Postfix) with SMTP id 2F1F76B0033 for ; Mon, 26 Aug 2013 19:53:20 -0400 (EDT) Received: from m3.gw.fujitsu.co.jp (unknown [10.0.50.73]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id 677CE3EE1D2 for ; Tue, 27 Aug 2013 08:53:18 +0900 (JST) Received: from smail (m3 [127.0.0.1]) by outgoing.m3.gw.fujitsu.co.jp (Postfix) with ESMTP id 57EAB45DEBA for ; Tue, 27 Aug 2013 08:53:18 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (s3.gw.fujitsu.co.jp [10.0.50.93]) by m3.gw.fujitsu.co.jp (Postfix) with ESMTP id 437C245DEB7 for ; Tue, 27 Aug 2013 08:53:18 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 3582E1DB803F for ; Tue, 27 Aug 2013 08:53:18 +0900 (JST) Received: from g01jpfmpwkw01.exch.g01.fujitsu.local (g01jpfmpwkw01.exch.g01.fujitsu.local [10.0.193.38]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id E00C51DB803C for ; Tue, 27 Aug 2013 08:53:17 +0900 (JST) Message-ID: <521BE989.4090100@jp.fujitsu.com> Date: Tue, 27 Aug 2013 08:49:29 +0900 From: Yasuaki Ishimatsu MIME-Version: 1.0 Subject: Re: [PATCH v2] [BUGFIX] drivers/base: fix show_mem_removable to handle missing sections References: <20130823162317.GB10988@sgi.com> In-Reply-To: <20130823162317.GB10988@sgi.com> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Russ Anderson Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Greg Kroah-Hartman , "Rafael J. Wysocki" , Yinghai Lu (2013/08/24 1:23), Russ Anderson wrote: > "cat /sys/devices/system/memory/memory*/removable" crashed the system. > > The problem is that show_mem_removable() is passing a > bad pfn to is_mem_section_removable(), which causes > if (!node_online(page_to_nid(page))) to blow up. > Why is it passing in a bad pfn? > > show_mem_removable() will loop sections_per_block times. > sections_per_block is 16, but mem->section_count is 8, > indicating holes in this memory block. Checking that > the memory section is present before checking to see > if the memory section is removable fixes the problem. > > v2: Add change suggested by Yasuaki Ishimatsu. > > Signed-off-by: Russ Anderson Reviewed-by: Yasuaki Ishimatsu Thanks, Yasuaki Ishimatsu > > > The failing output: > ----------------------------------------------------------- > harp5-sys:~ # cat /sys/devices/system/memory/memory*/removable > 0 > 1 > 1 > 1 > 1 > 1 > 1 > 1 > 1 > 1 > 1 > 1 > 1 > 1 > [ 372.111178] BUG: unable to handle kernel paging request at ffffea00c3200000 > [ 372.119230] IP: [] is_pageblock_removable_nolock+0x1/0x90 > [ 372.127022] PGD 83ffd4067 PUD 37bdfce067 PMD 0 > [ 372.132109] Oops: 0000 [#1] SMP > [ 372.135730] Modules linked in: autofs4 binfmt_misc rdma_ucm rdma_cm iw_cm ib_addr ib_srp scsi_transport_srp scsi_tgt ib_ipoib ib_cm ib_uverbs ib_umad iw_cxgb3 cxgb3 mdio mlx4_en mlx4_ib ib_sa mlx4_core ib_mthca ib_mad ib_core fuse nls_iso8859_1 nls_cp437 vfat fat joydev loop hid_generic usbhid hid hwperf(O) numatools(O) dm_mod iTCO_wdt ipv6 iTCO_vendor_support igb i2c_i801 ioatdma i2c_algo_bit ehci_pci pcspkr lpc_ich i2c_core ehci_hcd ptp sg mfd_core dca rtc_cmos pps_core mperf button xhci_hcd sd_mod crc_t10dif usbcore usb_common scsi_dh_emc scsi_dh_hp_sw scsi_dh_alua scsi_dh_rdac scsi_dh gru(O) xvma(O) xfs crc32c libcrc32c thermal sata_nv processor piix mptsas mptscsih scsi_transport_sas mptbase megaraid_sas fan thermal_sys hwmon ext3 jbd ata_piix ahci libahci libata scsi_mod > [ 372.213536] CPU: 4 PID: 5991 Comm: cat Tainted: G O 3.11.0-rc5-rja-uv+ #10 > [ 372.222173] Hardware name: SGI UV2000/ROMLEY, BIOS SGI UV 2000/3000 series BIOS 01/15/2013 > [ 372.231391] task: ffff88081f034580 ti: ffff880820022000 task.ti: ffff880820022000 > [ 372.239737] RIP: 0010:[] [] is_pageblock_removable_nolock+0x1/0x90 > [ 372.250229] RSP: 0018:ffff880820023df8 EFLAGS: 00010287 > [ 372.256151] RAX: 0000000000040000 RBX: ffffea00c3200000 RCX: 0000000000000004 > [ 372.264111] RDX: ffffea00c30b0000 RSI: 00000000001c0000 RDI: ffffea00c3200000 > [ 372.272071] RBP: ffff880820023e38 R08: 0000000000000000 R09: 0000000000000001 > [ 372.280030] R10: 0000000000000000 R11: 0000000000000001 R12: ffffea00c33c0000 > [ 372.287987] R13: 0000160000000000 R14: 6db6db6db6db6db7 R15: 0000000000000001 > [ 372.295945] FS: 00007ffff7fb2700(0000) GS:ffff88083fc80000(0000) knlGS:0000000000000000 > [ 372.304970] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 372.311378] CR2: ffffea00c3200000 CR3: 000000081b954000 CR4: 00000000000407e0 > [ 372.319335] Stack: > [ 372.321575] ffff880820023e38 ffffffff81161e94 ffffffff81d9e940 0000000000000009 > [ 372.329872] 0000000000000000 ffff8817bb97b800 ffff88081e928000 ffff8817bb97b870 > [ 372.338167] ffff880820023e68 ffffffff813730d1 fffffffffffffffb ffffffff81a97600 > [ 372.346463] Call Trace: > [ 372.349201] [] ? is_mem_section_removable+0x84/0x110 > [ 372.356579] [] show_mem_removable+0x41/0x70 > [ 372.363094] [] dev_attr_show+0x2a/0x60 > [ 372.369122] [] sysfs_read_file+0xf7/0x1c0 > [ 372.375441] [] vfs_read+0xc8/0x130 > [ 372.381076] [] SyS_read+0x5d/0xa0 > [ 372.386624] [] system_call_fastpath+0x16/0x1b > [ 372.393313] Code: 01 00 00 00 e9 3c ff ff ff 90 0f b6 4a 30 44 89 d8 d3 e0 89 c1 83 e9 01 48 63 c9 49 01 c8 eb 92 66 2e 0f 1f 84 00 00 00 00 00 55 <48> 8b 0f 49 89 f8 48 89 e5 48 89 ca 48 c1 ea 36 0f a3 15 d8 2f > [ 372.415032] RIP [] is_pageblock_removable_nolock+0x1/0x90 > [ 372.422905] RSP > [ 372.426792] CR2: ffffea00c3200000 > --------------------------------------------------------- > > > --- > drivers/base/memory.c | 2 ++ > 1 file changed, 2 insertions(+) > > Index: linux/drivers/base/memory.c > =================================================================== > --- linux.orig/drivers/base/memory.c 2013-08-23 11:09:32.433772674 -0500 > +++ linux/drivers/base/memory.c 2013-08-23 11:21:13.338046321 -0500 > @@ -141,6 +141,8 @@ static ssize_t show_mem_removable(struct > container_of(dev, struct memory_block, dev); > > for (i = 0; i < sections_per_block; i++) { > + if (!present_section_nr(mem->start_section_nr + i)) > + continue; > pfn = section_nr_to_pfn(mem->start_section_nr + i); > ret &= is_mem_section_removable(pfn, PAGES_PER_SECTION); > } > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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