Messages in this thread | | | Subject | Re: Warning from AMD IOMMU performance counters | From | Laura Abbott <> | Date | Mon, 22 Feb 2016 17:36:09 -0800 |
| |
On 02/21/2016 05:52 PM, Wan Zongshun wrote: > > > -------- Original Message -------- >> Hi, >> >> Since about 4.4, we've been seeing reports of this warning on every boot >> from some users: >> >> WARNING: CPU: 2 PID: 1 at drivers/iommu/amd_iommu_init.c:2301 >> amd_iommu_pc_get_set_reg_val+0xa8/0xe0() >> Modules linked in: >> CPU: 2 PID: 1 Comm: swapper/0 Not tainted 4.4.2-300.fc23.x86_64 #1 >> Hardware name: Hewlett-Packard HP EliteBook 755 G2/221C, BIOS M84 Ver. >> 01.10 10/20/2015 >> 0000000000000000 0000000026124b43 ffff88042d687d20 ffffffff813b0c9f >> 0000000000000000 ffff88042d687d58 ffffffff810a2f12 ffff88042f014800 >> 0000000000000040 0000000000000000 ffffffff81d6c73d 0000000000000000 >> Call Trace: >> [<ffffffff813b0c9f>] dump_stack+0x44/0x55 >> [<ffffffff810a2f12>] warn_slowpath_common+0x82/0xc0 >> [<ffffffff81d6c73d>] ? memblock_find_dma_reserve+0x16a/0x16a >> [<ffffffff810a305a>] warn_slowpath_null+0x1a/0x20 >> [<ffffffff814d3f48>] amd_iommu_pc_get_set_reg_val+0xa8/0xe0 >> [<ffffffff81dafda7>] iommu_go_to_state+0x4d6/0x1384 >> [<ffffffff813c02ea>] ? kvasprintf+0x7a/0xa0 >> [<ffffffff81d6c73d>] ? memblock_find_dma_reserve+0x16a/0x16a >> [<ffffffff81db0cbd>] amd_iommu_init+0x13/0x201 >> [<ffffffff81d6c74f>] pci_iommu_init+0x12/0x3c >> [<ffffffff81002123>] do_one_initcall+0xb3/0x200 >> [<ffffffff810c0935>] ? parse_args+0x295/0x4b0 >> [<ffffffff81d621c8>] kernel_init_freeable+0x189/0x223 >> [<ffffffff8178dc00>] ? rest_init+0x80/0x80 >> [<ffffffff8178dc0e>] kernel_init+0xe/0xe0 >> [<ffffffff81799c8f>] ret_from_fork+0x3f/0x70 >> [<ffffffff8178dc00>] ? rest_init+0x80/0x80 >> >> Full bugzilla https://bugzilla.redhat.com/show_bug.cgi?id=1310258 >> >> Any idea what might be causing this spew? > > I also see this warning. > > Suravee's the one of this patch series might be fix this issue, you can try it. > > [PATCH V4 0/6] perf/amd/iommu: Enable multi-IOMMU support > >
That patch had other dependencies. I brought what I thought were enough of them in to at least compile for the reporter to test (perf_event changes from Borislav Petkov). Apparently the kernel doesn't boot with the series so suspect there is an integration issue somewhere. I'm going to see if I can more information from the reporter about what exactly went wrong to see if I need more dependencies.
It would be nice to get a single patch which could be applied to stable. Tainting the kernel immediately on bootup makes sorting through problems more difficult.
Thanks, Laura
| |