<added some cc>

If this patch fixes a bug can it be applied?  I hadn't seen any
followup, sorry if it was in another thread, I'm still catching up
after being out.

On Sat, Mar 20, 2010 at 3:21 AM, Yinghai Lu <yinghai@kernel.org> wrote:
quoted text
> found when a lot of ixgbevf are used with intel iommu, will get crash
>
>>
>> eth304 ip=192.171.178.102 mac=56:95:16:88:4C:C1 pci=0000:0e:18.3 drv=ixgbevf
>> eth305 ip=192.171.179.102 mac=D6:41:8C:4A:87:B3 pci=0000:0e:18.5 drv=ixgbevf
>> [ 9534.886519] BUG: unable to handle kernel NULL pointer dereference at
>> 0000000000000008
>> [ 9534.889775] Call Trace:
>> [ 9534.889775]  [<ffffffff81406a3d>] domain_remove_dev_info+0x34/0xcf
>> [ 9534.889775]  [<ffffffff81408a1d>] domain_exit+0x23/0xc4
>> [ 9534.889775]  [<ffffffff81409c1c>] T.953+0x173/0x342
>> [ 9534.889775]  [<ffffffff81409fd0>] __intel_map_single+0x63/0x1b3
>> [ 9534.889775]  [<ffffffff8140a22a>] intel_alloc_coherent+0xc7/0xee
>> [ 9534.889775]  [<ffffffff816c3e7d>] ? ixgbevf_setup_tx_resources+0x2f/0x12c
>> [ 9534.889775]  [<ffffffff816c3f36>] ixgbevf_setup_tx_resources+0xe8/0x12c
>> [ 9534.889775]  [<ffffffff816c42d2>] ixgbevf_open+0x7a/0x160
>> [ 9534.889775]  [<ffffffff81adf21e>] __dev_open+0x8e/0xbc
>> [ 9534.889775]  [<ffffffff81adb716>] __dev_change_flags+0xad/0x130
>> [ 9534.889775]  [<ffffffff81adf15a>] dev_change_flags+0x21/0x57
>> [ 9534.889775]  [<ffffffff81b211e5>] devinet_ioctl+0x29d/0x541
>> [ 9534.889775]  [<ffffffff810a4b92>] ? trace_hardirqs_off_caller+0x1f/0xa9
>> [ 9534.889775]  [<ffffffff81b22801>] inet_ioctl+0x8f/0xa7
>> [ 9534.889775]  [<ffffffff81acc258>] sock_do_ioctl+0x29/0x48
>> [ 9534.889775]  [<ffffffff81acca64>] sock_ioctl+0x1fe/0x20d
>> [ 9534.889775]  [<ffffffff8113b86a>] vfs_ioctl+0x32/0xa6
>> [ 9534.889775]  [<ffffffff8113bd04>] do_vfs_ioctl+0x2b0/0x2cb
>> [ 9534.889775]  [<ffffffff81033c4c>] ? sysret_check+0x27/0x62
>> [ 9534.889775]  [<ffffffff8113bd66>] sys_ioctl+0x47/0x6a
>> [ 9534.889775]  [<ffffffff81033c1b>] system_call_fastpath+0x16/0x1b
>> [ 9534.889775] Code: cd 7f cc ff 41 54 9d 48 83 c4 20 5b 41 5c 41 5d 41
>> 5e c9 c3 55 48 89 e5 e8 11 ff ff ff c9 c3 55 48 89 e5 53 48 89 fb 48 83
>> ec 08 <48> 8b 47 08 4c 8b 00 49 39 f8 74 1d 48 89 f9 48 c7 c2 7f e9 18
>> [ 9534.889775] RIP  [<ffffffff813ddf94>] list_del+0xc/0x8b
>> [ 9534.889775]  RSP <ffff88c070373af8>
>> [ 9534.889775] CR2: 0000000000000008
>> [ 9534.889775] ---[ end trace 072bd8cdb08a760c ]---
>> xifconfig8_2x_vf.sh: line 10: 28555 Killed                  ifconfig
>> $DEV $IP
>>
>
> when intel_iommu=off or iommu=pt is used, will work well.
>
> root cause:
> domain is initialized after trying attached it,
>
> if it can not be attached, don't call domain_exit yet. it will cause kernel crash in domain_exit()
>
> after patch will will get error instead of crash.
>
> [ 1781.910241] IOMMU: no free domain ids
> [ 1781.910244] Allocating domain for 0000:d0:1f.5 failed
> SIOCSIFFLAGS: Cannot allocate memory
>
>
> Signed-off-by: Yinghai Lu <yinghai@kernel.org>
>
> Index: linux-2.6/drivers/pci/intel-iommu.c
> ===================================================================
> --- linux-2.6.orig/drivers/pci/intel-iommu.c
> +++ linux-2.6/drivers/pci/intel-iommu.c
> @@ -1853,7 +1857,7 @@ static struct dmar_domain *get_domain_fo
>
>        ret = iommu_attach_domain(domain, iommu);
>        if (ret) {
> -               domain_exit(domain);
> +               free_domain_mem(domain);
>                goto error;
>        }
>
--
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