Messages in this thread | | | Subject | Re: [RFC PATCH v2] iommu/amd: gray the 'irq_remap_table' object for kmemleak | From | Michael Wang <> | Date | Fri, 20 Nov 2015 13:31:36 +0100 |
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On 11/20/2015 12:33 PM, Michael Wang wrote: > The kmemleak testing on 3.18.24 show: > > unreferenced object 0xffff880233ff9010 (size 16): > comm "swapper/0", pid 1, jiffies 4294937440 (age 2010.490s) > hex dump (first 16 bytes): > 0a 0a 00 00 20 00 00 00 00 44 fb 33 02 88 ff ff .... ....D.3.... > backtrace: > [<ffffffff8118192d>] create_object+0x10d/0x2d0 > [<ffffffff815c2d4b>] kmemleak_alloc+0x5b/0xc0 > [<ffffffff8116dd19>] kmem_cache_alloc_trace+0xb9/0x160 > [<ffffffff814ffe51>] get_irq_table+0x151/0x380 > > This is caused by the 'irq_lookup_table' was allocated with > __get_free_pages() which won't create kmemleak object, thus it's > pointers won't be count as referencing 'irq_remap_table' in > kmemleak scan. > > The 'irq_remap_table' won't be freed after initialized, doesn't > make sense to check it's leaking. > > This patch mark the 'irq_remap_table' object as 'gray' to stop > the 'false positives' report. > > Signed-off-by: Michael Wang <yun.wang@profitbricks.com>
Reported-by: Danil Kipnis <danil.kipnis@profitbricks.com>
Regards, Michael Wang
> --- > v2: > Use kmemleak_not_leak() instead of kmemleak_ignore() since > the 'irq_remap_table' itself also contain pointer. > > drivers/iommu/amd_iommu.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c > index 8b2be1e..87a1a88 100644 > --- a/drivers/iommu/amd_iommu.c > +++ b/drivers/iommu/amd_iommu.c > @@ -3603,6 +3603,7 @@ static struct irq_remap_table *get_irq_table(u16 devid, bool ioapic) > } > > irq_lookup_table[devid] = table; > + kmemleak_not_leak(table); > set_dte_irq_entry(devid, table); > iommu_flush_dte(iommu, devid); > if (devid != alias) { >
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