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SubjectRE: [RESEND,PATCH] DCA, x86: fix invalid memory access in DCA core
Date
On Mon, May 07, 2012 5:58 PM, Jiang Liu <liuj97@gmail.com> wrote:
>
>From: Jiang Liu <jiang.liu@huawei.com>
>
>When unregister_dca_providers() is called, it will remove all registered
>providers from the dca_providrers list by calling list_del(&dca->node).
>list_del(node) poisons node->next and node->prev as 0xDEADBEEF and
>0xBEEFDEAD.
>Later when unregister_dca_provider() is called to remove a DCA provier,
>it calls list_del(&dca->node) to remove the dca from the list again,
>but dca->node has already been poisoned, then causes invalid memory
>access.
>
>The solution here is to use list_del_init(&dca->node) instead of
>list_del(&dca->node) in function unregister_dca_providers(), so it won't
>cause invalid memory access in unregister_dca_provider() later.
>
>---
>
>This issue is triggered when hot-removing IOHs on Intel platforms, which
>will remove all IOAT devices built in the IOHs.
>
>ioatdma 0000:80:16.7: Removing dma and dca services
>ioatdma 0000:80:16.7: PCI INT D disabled
>ioatdma 0000:80:16.6: Removing dma and dca services
>ioatdma 0000:80:16.7: Removing dma and dca services
>ioatdma 0000:80:16.7: PCI INT D disabled
>ioatdma 0000:80:16.6: Removing dma and dca services
>ioatdma 0000:80:16.6: PCI INT C disabled
>ioatdma 0000:00:16.0: Removing dma and dca services
>------------[ cut here ]------------
>WARNING: at lib/list_debug.c:47 __list_del_entry+0x63/0xd0()
>Hardware name: System x3850 X5 -[7143O3G]-
>list_del corruption, ffff880463540bc0->next is LIST_POISON1
>(dead000000100100)
>Modules linked in: ebtable_nat ebtables ipt_MASQUERADE iptable_nat
>nf_nat xt_CHECKSUM iptable_mangle bridge stp llc autofs4 sunrpc
>cpufreq_ondemand acpi_cpufreq freq_table mperf ipt_REJECT
>nf_conntrack_ipv4 nf_defrag_ipv4 iptable_filter ip_tables ip6t_REJECT
>nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter
>ip6_tables ipv6 vfat fat vhost_net macvtap macvlan tun kvm_intel kvm uinput
>microcode pcspkr serio_raw pmcraid sg be2net cdc_ether usbnet mii i2c_i801
>i2c_core iTCO_wdt iTCO_vendor_support shpchp ioatdma i7core_edac
>edac_core igb dca e1000e bnx2 ext4 mbcache jbd2 sr_mod cdrom sd_mod
>crc_t10dif qla2xxx pata_acpi ata_generic ata_piix bfa scsi_transport_fc
>scsi_tgt megaraid_sas dm_mirror dm_region_hash dm_log dm_mod [last
>unloaded: scsi_wait_scan]
>Pid: 10049, comm: bash.sh Not tainted 3.2.0IOAT+ #5
>Call Trace:
> [<ffffffff8106426f>] warn_slowpath_common+0x7f/0xc0
> [<ffffffff81064366>] warn_slowpath_fmt+0x46/0x50
> [<ffffffff8108c675>] ? __blocking_notifier_call_chain+0x65/0x80
> [<ffffffff81256073>] __list_del_entry+0x63/0xd0
> [<ffffffff812560f1>] list_del+0x11/0x40
> [<ffffffffa001b2e2>] unregister_dca_provider+0x42/0xe0 [dca]
> [<ffffffffa021f87d>] ioat_remove+0x43/0x67 [ioatdma]
> [<ffffffff8126b1a2>] pci_device_remove+0x52/0x120
> [<ffffffff8132b2dc>] __device_release_driver+0x7c/0xe0
> [<ffffffff8132b42d>] device_release_driver+0x2d/0x40
> [<ffffffff8132a871>] driver_unbind+0xa1/0xc0
> [<ffffffff81329cbc>] drv_attr_store+0x2c/0x30
> [<ffffffff811d72ef>] sysfs_write_file+0xef/0x170
> [<ffffffff81167338>] vfs_write+0xc8/0x190
> [<ffffffff81167501>] sys_write+0x51/0x90
> [<ffffffff814fa382>] system_call_fastpath+0x16/0x1b
>---[ end trace b81b51e7c494ec0d ]---
>BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
>IP: [<ffffffffa001b360>] unregister_dca_provider+0xc0/0xe0 [dca]
>PGD 1465b48067 PUD 1465035067 PMD 0
>Oops: 0000 [#1] SMP
>CPU 57
>Modules linked in: ebtable_nat ebtables ipt_MASQUERADE iptable_nat
>nf_nat xt_CHECKSUM iptable_mangle bridge stp llc autofs4 sunrpc
>cpufreq_ondemand acpi_cpufreq freq_table mperf ipt_REJECT
>nf_conntrack_ipv4 nf_defrag_ipv4 iptable_filter ip_tables ip6t_REJECT
>nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter
>ip6_tables ipv6 vfat fat vhost_net macvtap macvlan tun kvm_intel kvm uinput
>microcode pcspkr serio_raw pmcraid sg be2net cdc_ether usbnet mii i2c_i801
>i2c_core iTCO_wdt iTCO_vendor_support shpchp ioatdma i7core_edac
>edac_core igb dca e1000e bnx2 ext4 mbcache jbd2 sr_mod cdrom sd_mod
>crc_t10dif qla2xxx pata_acpi ata_generic ata_piix bfa scsi_transport_fc
>scsi_tgt megaraid_sas dm_mirror dm_region_hash dm_log dm_mod [last
>unloaded: scsi_wait_scan]
>
>Pid: 10049, comm: bash.sh Tainted: G W 3.2.0IOAT+ #5 IBM System x3850
>X5 -[7143O3G]-/Node 1, Processor Card
>RIP: 0010:[<ffffffffa001b360>] [<ffffffffa001b360>]
>unregister_dca_provider+0xc0/0xe0 [dca]
>RSP: 0018:ffff880c4eafbdb8 EFLAGS: 00010046
>RAX: 0000000000000010 RBX: ffff880463540bc0 RCX: 0000000000002288
>RDX: ffff881465a51800 RSI: 0000000000000046 RDI: 0000000000000009
>RBP: ffff880c4eafbdd8 R08: 0000000000000000 R09: 0000000000000000
>R10: 0000000000000010 R11: 000000000000000b R12: 0000000000000000
>R13: 0000000000000257 R14: ffff881465abe000 R15: ffff881464199840
>FS: 00007f91d8314700(0000) GS:ffff88147fd20000(0000)
>knlGS:0000000000000000
>CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>CR2: 0000000000000010 CR3: 0000001457b07000 CR4: 00000000000006e0
>DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
>Process bash.sh (pid: 10049, threadinfo ffff880c4eafa000, task
>ffff880c4e3b8af0)
>Stack:
> 0000000000000206 ffff88046133a218 ffff881465abe090 ffffffffa0222560
> ffff880c4eafbdf8 ffffffffa021f87d ffff881465abe090 ffff881465abe208
> ffff880c4eafbe28 ffffffff8126b1a2 ffff881465abe090 ffffffffa02225c0
>Call Trace:
> [<ffffffffa021f87d>] ioat_remove+0x43/0x67 [ioatdma]
> [<ffffffff8126b1a2>] pci_device_remove+0x52/0x120
> [<ffffffff8132b2dc>] __device_release_driver+0x7c/0xe0
> [<ffffffff8132b42d>] device_release_driver+0x2d/0x40
> [<ffffffff8132a871>] driver_unbind+0xa1/0xc0
> [<ffffffff81329cbc>] drv_attr_store+0x2c/0x30
> [<ffffffff811d72ef>] sysfs_write_file+0xef/0x170
> [<ffffffff81167338>] vfs_write+0xc8/0x190
> [<ffffffff81167501>] sys_write+0x51/0x90
> [<ffffffff814fa382>] system_call_fastpath+0x16/0x1b
>Code: c7 20 c0 01 a0 e8 51 6c 4d e1 48 89 df e8 c9 05 00 00 48 83 c4 08 5b 41 5c 41
>5d c9 c3 66 0f 1f 44 00 00 45 31 e4 49 8d 44 24 10 <49> 39 44 24 10 75 c9 4c 89 e7
>e8 71 ad 23 e1 4c 89 e7 e8 19 7b
>RIP [<ffffffffa001b360>] unregister_dca_provider+0xc0/0xe0 [dca]
> RSP <ffff880c4eafbdb8>
>CR2: 0000000000000010
>---[ end trace b81b51e7c494ec0e ]---
>
>Signed-off-by: Jiang Liu <liuj97@gmail.com>
>---
> drivers/dca/dca-core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/drivers/dca/dca-core.c b/drivers/dca/dca-core.c
>index bc6f5fa..075c4bd 100644
>--- a/drivers/dca/dca-core.c
>+++ b/drivers/dca/dca-core.c
>@@ -121,7 +121,7 @@ static void unregister_dca_providers(void)
>
> list_for_each_entry_safe(dca, _dca, &unregistered_providers, node)
>{
> dca_sysfs_remove_provider(dca);
>- list_del(&dca->node);
>+ list_del_init(&dca->node);
> }
> }
>
>--
>1.7.9.5

Thanks for reporting and debugging. However I think this patch is not
the right solution. Dca should be prevented from trying to unregister
any provider after providers have been blocked and
unregister_dca_providers() has been called.
I will prepare a patch.

Thanks,
Maciej
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