From: Armin Wolf <W_Armin@xxxxxx> [ Upstream commit 94a370fc8def6038dbc02199db9584b0b3690f1a ] The ACPI sysfs code will fail to initialize if acpi_kobj is NULL, together with some ACPI drivers. Follow the other firmware subsystems and bail out if the kobject cannot be registered. Signed-off-by: Armin Wolf <W_Armin@xxxxxx> Link: https://patch.msgid.link/20250518185111.3560-2-W_Armin@xxxxxx Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- **YES** This commit should be backported to stable kernel trees. Here's the detailed analysis: **Bug Fix Nature**: The commit fixes a real bug where ACPI initialization continues silently even when `acpi_kobj` registration fails. This creates an inconsistent system state where ACPI sysfs functionality and some drivers that depend on `acpi_kobj` will fail later without clear indication of the root cause. **Code Change Analysis**: - Changes `pr_debug()` to `pr_err()` for better visibility of the failure - Returns `-ENOMEM` immediately when `kobject_create_and_add()` fails instead of continuing - The existing `kobject_put(acpi_kobj)` cleanup in the error path after `acpi_bus_init()` is already present **Comparison with Similar Commits**: This follows the exact pattern of Similar Commit #1 (Status: YES) which added `kobject_put()` cleanup. Both commits address resource management issues in the same function (`acpi_init`) and represent important bugfixes with minimal risk. **Risk Assessment**: - Very low risk - only affects the error path when kobject creation fails - Early failure is better than silent failure leading to confusing symptoms later - Change is contained to a single function with clear error handling - Consistent with how other firmware subsystems handle kobject registration failures **Stable Tree Criteria Met**: - Fixes important bug affecting system reliability - Minimal and contained change - No architectural modifications - Clear improvement in error handling and debugging The commit addresses a legitimate reliability issue where ACPI would continue initialization with a NULL `acpi_kobj`, leading to failures in dependent subsystems that would be harder to diagnose than an early, clear failure. drivers/acpi/bus.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c index 058910af82bca..c2ab2783303f2 100644 --- a/drivers/acpi/bus.c +++ b/drivers/acpi/bus.c @@ -1446,8 +1446,10 @@ static int __init acpi_init(void) } acpi_kobj = kobject_create_and_add("acpi", firmware_kobj); - if (!acpi_kobj) - pr_debug("%s: kset create error\n", __func__); + if (!acpi_kobj) { + pr_err("Failed to register kobject\n"); + return -ENOMEM; + } init_prmt(); acpi_init_pcc(); -- 2.39.5
