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That hook (tegra234_mc_icc_aggregate / >> tegra264_mc_icc_aggregate) uses container_of() to recover 'mc', >> which is only valid when the icc_provider is embedded in struct >> tegra_mc. For an EMC node the provider is embedded in struct >> tegra186_emc, so 'mc' points into unrelated memory. >> >> This stayed harmless until commit faafd6ca7e6e ("memory: tegra: >> make icc_set_bw return zero if BWMGR not supported") added an >> unconditional read of mc->bwmgr_mrq_supported at the top of the >> hook. UBSAN catches the stray load on every EMC aggregation: >> >> UBSAN: invalid-load in drivers/memory/tegra/tegra234.c:1104:9 >> load of value 112 is not a valid value for type '_Bool' >> >> No functional impact in practice, since the hook's only other mc >> dereference (mc->num_channels) sits inside a >> TEGRA_ICC_MC_CPU_CLUSTER* branch that EMC nodes never enter. >> >> Fix this by setting the EMC provider's aggregate hook to >> icc_std_aggregate, instead of borrowing the MC's hook. The MC >> providers continue using their own aggregate hooks, where >> container_of() correctly resolves to struct tegra_mc. >> >> Reported-by: Jon Hunter > > I assume these reports were offlist. Otherwise this has a valid > checkpatch warning. Yes some of our internal testing flagged this and I had asked Sumit to take a look. Cheers Jon -- nvpublic