Bug Report: L4T 5.10 Kernel: DMA_API_DEBUG=y produces stack traces
I have enclosed the full kernel log which contains the stack traces.
DMA-API: arm-smmu 12000000.iommu: device driver tries to sync DMA memory it has not allocated [device address=0x00000007fdcad000] [size=8 bytes]
DMA-API: exceeded 7 overlapping mappings of cacheline 0x0000000001800000
I have recompiled the L4T 5.10 kernel with and without the RT patches applied, in both cases the stack traces exist. The first stack trace is alarming as 8 bytes of garbage are (possibly) being written to a device. You can reproduce these errors by adding the following to 5.10 kernel config:
- CONFIG_DMA_API_DEBUG=y
- CONFIG_DMA_API_DEBUG_SG=y
L4T kernel commit 150754e3de53c81a0be6aab613700bd15414790c “iommu: arm-smmu: io-pagetable: Add dma_sync API” appears to be related to stack trace #1. The relevant kernel source is from the following:
git clone “https://nv-tegra.nvidia.com/r/linux-5.10”
git checkout origin/l4t/l4t-r35.1.ga-5.10
I’m concerned these DMA errors may indicate some instability in the system that may be exacerbated by the RT patchset.
l4t-dmesg.txt (77.0 KB)