[PATCH] pmdomain: arm: scmi: Fix genpd leak on provider registration failure

[Sudeep Holla]

If of_genpd_add_provider_onecell() fails during probe, the previously
created generic power domains are not removed, leading to a memory leak
and potential kernel crash later in genpd_debug_add().

Add proper error handling to unwind the initialized domains before
returning from probe to ensure all resources are correctly released on
failure.

Example crash trace observed without this fix:

  | Unable to handle kernel paging request at virtual address fffffffffffffc70
  | CPU: 1 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.18.0-rc1 #405 PREEMPT
  | Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform
  | pstate: 00000005 (nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
  | pc : genpd_debug_add+0x2c/0x160
  | lr : genpd_debug_init+0x74/0x98
  | Call trace:
  |  genpd_debug_add+0x2c/0x160 (P)
  |  genpd_debug_init+0x74/0x98
  |  do_one_initcall+0xd0/0x2d8
  |  do_initcall_level+0xa0/0x140
  |  do_initcalls+0x60/0xa8
  |  do_basic_setup+0x28/0x40
  |  kernel_init_freeable+0xe8/0x170
  |  kernel_init+0x2c/0x140
  |  ret_from_fork+0x10/0x20

Fixes: 898216c97ed2 ("firmware: arm_scmi: add device power domain support using genpd")
Signed-off-by: Sudeep Holla <sudeep.holla at arm.com>
---
 drivers/pmdomain/arm/scmi_pm_domain.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/pmdomain/arm/scmi_pm_domain.c b/drivers/pmdomain/arm/scmi_pm_domain.c
index 8fe1c0a501c9..b5e2ffd5ea64 100644
--- a/drivers/pmdomain/arm/scmi_pm_domain.c
+++ b/drivers/pmdomain/arm/scmi_pm_domain.c
@@ -41,7 +41,7 @@ static int scmi_pd_power_off(struct generic_pm_domain *domain)
 
 static int scmi_pm_domain_probe(struct scmi_device *sdev)
 {
-	int num_domains, i;
+	int num_domains, i, ret;
 	struct device *dev = &sdev->dev;
 	struct device_node *np = dev->of_node;
 	struct scmi_pm_domain *scmi_pd;
@@ -108,9 +108,18 @@ static int scmi_pm_domain_probe(struct scmi_device *sdev)
 	scmi_pd_data->domains = domains;
 	scmi_pd_data->num_domains = num_domains;
 
+	ret = of_genpd_add_provider_onecell(np, scmi_pd_data);
+	if (ret)
+		goto err_rm_genpds;
+
 	dev_set_drvdata(dev, scmi_pd_data);
 
-	return of_genpd_add_provider_onecell(np, scmi_pd_data);
+	return 0;
+err_rm_genpds:
+	for (i = num_domains - 1; i >= 0; i--)
+		pm_genpd_remove(domains[i]);
+
+	return ret;
 }
 
 static void scmi_pm_domain_remove(struct scmi_device *sdev)
-- 
2.34.1