]> git.ipfire.org Git - thirdparty/linux.git/commit
memory: tegra186-emc: stop borrowing MC aggregate hook for EMC
authorSumit Gupta <sumitg@nvidia.com>
Wed, 27 May 2026 14:01:25 +0000 (19:31 +0530)
committerKrzysztof Kozlowski <krzk@kernel.org>
Tue, 9 Jun 2026 15:00:30 +0000 (17:00 +0200)
commit2e05f3d6005d9aa3e2e423d2471f290d9ccbe3d2
tree58fe59d86eb78436439003ed898c2320dde0c512
parentd530ed059dac445dc5b81d564adf1952b5c4adba
memory: tegra186-emc: stop borrowing MC aggregate hook for EMC

tegra186_emc_interconnect_init() copies the MC's ICC aggregate hook
into the EMC provider.  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 <jonathanh@nvidia.com>
Fixes: 9a38cb27668e ("memory: tegra: Add interconnect support for DRAM scaling in Tegra234")
Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Link: https://patch.msgid.link/20260527140127.49172-2-sumitg@nvidia.com
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
drivers/memory/tegra/tegra186-emc.c