On 02/05/2025 12:11 pm, Leo Yan wrote:

On platforms with a static replicator, a kernel panic occurs during boot:

[ 4.999406] replicator_probe+0x1f8/0x360 [ 5.003455] replicator_platform_probe+0x64/0xd8 [ 5.008115] platform_probe+0x70/0xf0 [ 5.011812] really_probe+0xc4/0x2a8 [ 5.015417] __driver_probe_device+0x80/0x140 [ 5.019813] driver_probe_device+0xe4/0x170 [ 5.024032] __driver_attach+0x9c/0x1b0 [ 5.027900] bus_for_each_dev+0x7c/0xe8 [ 5.031769] driver_attach+0x2c/0x40 [ 5.035373] bus_add_driver+0xec/0x218 [ 5.039154] driver_register+0x68/0x138 [ 5.043023] __platform_driver_register+0x2c/0x40 [ 5.047771] coresight_init_driver+0x4c/0xe0 [ 5.052079] replicator_init+0x30/0x48 [ 5.055865] do_one_initcall+0x4c/0x280 [ 5.059736] kernel_init_freeable+0x1ec/0x3c8 [ 5.064134] kernel_init+0x28/0x1f0 [ 5.067655] ret_from_fork+0x10/0x20

A static replicator doesn't have registers, so accessing the claim register results in a NULL pointer deference. Fixes the issue by accessing the claim registers only after the I/O resource has been successfully mapped.

Fixes: 6f4c6f70575f ("coresight: Clear self hosted claim tag on probe") Signed-off-by: Leo Yan leo.yan@arm.com

---

drivers/hwtracing/coresight/coresight-replicator.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-replicator.c b/drivers/hwtracing/coresight/coresight-replicator.c index f1d2f764e898..06efd2b01a0f 100644 --- a/drivers/hwtracing/coresight/coresight-replicator.c +++ b/drivers/hwtracing/coresight/coresight-replicator.c @@ -262,6 +262,7 @@ static int replicator_probe(struct device *dev, struct resource *res) drvdata->base = base; desc.groups = replicator_groups; desc.access = CSDEV_ACCESS_IOMEM(base);

• coresight_clear_self_claim_tag(&desc.access);
  

  }

if (fwnode_property_present(dev_fwnode(dev), @@ -284,7 +285,6 @@ static int replicator_probe(struct device *dev, struct resource *res) desc.pdata = dev->platform_data; desc.dev = dev;

• coresight_clear_self_claim_tag(&desc.access); drvdata->csdev = coresight_register(&desc); if (IS_ERR(drvdata->csdev)) { ret = PTR_ERR(drvdata->csdev);

Oops. The other occurrence of this is the funnel, but I got that one right.

Reviewed-by: James Clark james.clark@linaro.org