From 36c0de02575ce59dfd879eb4ef63d53a68bbf9ce Mon Sep 17 00:00:00 2001 From: Robin Murphy Date: Tue, 3 Feb 2026 14:07:29 +0000 Subject: perf/arm-cmn: Reject unsupported hardware configurations So far we've been fairly lax about accepting both unknown CMN models (at least with a warning), and unknown revisions of those which we do know, as although things do frequently change between releases, typically enough remains the same to be somewhat useful for at least some basic bringup checks. However, we also make assumptions of the maximum supported sizes and numbers of things in various places, and there's no guarantee that something new might not be bigger and lead to nasty array overflows. Make sure we only try to run on things that actually match our assumptions and so will not risk memory corruption. We have at least always failed on completely unknown node types, so update that error message for clarity and consistency too. Cc: stable@vger.kernel.org Fixes: 7819e05a0dce ("perf/arm-cmn: Revamp model detection") Reviewed-by: Ilkka Koskinen Signed-off-by: Robin Murphy Signed-off-by: Will Deacon --- drivers/perf/arm-cmn.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c index 651edd73bfcb..4fbafc4b7984 100644 --- a/drivers/perf/arm-cmn.c +++ b/drivers/perf/arm-cmn.c @@ -2422,6 +2422,15 @@ static int arm_cmn_discover(struct arm_cmn *cmn, unsigned int rgn_offset) arm_cmn_init_node_info(cmn, reg & CMN_CHILD_NODE_ADDR, dn); dn->portid_bits = xp->portid_bits; dn->deviceid_bits = xp->deviceid_bits; + /* + * Logical IDs are assigned from 0 per node type, so as + * soon as we see one bigger than expected, we can assume + * there are more than we can cope with. + */ + if (dn->logid > CMN_MAX_NODES_PER_EVENT) { + dev_err(cmn->dev, "Node ID invalid for supported CMN versions: %d\n", dn->logid); + return -ENODEV; + } switch (dn->type) { case CMN_TYPE_DTC: @@ -2471,7 +2480,7 @@ static int arm_cmn_discover(struct arm_cmn *cmn, unsigned int rgn_offset) break; /* Something has gone horribly wrong */ default: - dev_err(cmn->dev, "invalid device node type: 0x%x\n", dn->type); + dev_err(cmn->dev, "Device node type invalid for supported CMN versions: 0x%x\n", dn->type); return -ENODEV; } } @@ -2499,6 +2508,10 @@ static int arm_cmn_discover(struct arm_cmn *cmn, unsigned int rgn_offset) cmn->mesh_x = cmn->num_xps; cmn->mesh_y = cmn->num_xps / cmn->mesh_x; + if (max(cmn->mesh_x, cmn->mesh_y) > CMN_MAX_DIMENSION) { + dev_err(cmn->dev, "Mesh size invalid for supported CMN versions: %dx%d\n", cmn->mesh_x, cmn->mesh_y); + return -ENODEV; + } /* 1x1 config plays havoc with XP event encodings */ if (cmn->num_xps == 1) dev_warn(cmn->dev, "1x1 config not fully supported, translate XP events manually\n"); -- cgit v1.2.3