| Message ID | 11783109.O9o76ZdvQC@kreacher (mailing list archive) |
|---|---|
| State | Mainlined, archived |
| Headers | show |
| Series | None | expand |
Hi, On 6/16/21 8:00 PM, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > If acpi_add_single_object() runs concurrently with respect to > acpi_scan_clear_dep() which deletes a dependencies list entry where > the device being added is the consumer, the device's dep_unmet > counter may not be updated to reflect that change. > > Namely, if the dependencies list entry is deleted right after > calling acpi_scan_dep_init() and before calling acpi_device_add(), > acpi_scan_clear_dep() will not find the device object corresponding > to the consumer device ACPI handle and it will not update its > dep_unmet counter to reflect the deletion of the list entry. > Consequently, the dep_unmet counter of the device will never > become zero going forward which may prevent it from being > completely enumerated. > > To address this problem, modify acpi_add_single_object() to run > acpi_tie_acpi_dev(), to attach the ACPI device object created by it > to the corresponding ACPI namespace node, under acpi_dep_list_lock > along with acpi_scan_dep_init() whenever the latter is called. > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > Reviewed-by: Hans de Goede <hdegoede@redhat.com> FWIW this looks good to me now. Regards, Hans > --- > > -> v2: > * Fix memory leak spotted by Hans. > * Add the R-by tag from Hans. > > --- > drivers/acpi/scan.c | 50 ++++++++++++++++++++++++++++++++------------------ > 1 file changed, 32 insertions(+), 18 deletions(-) > > Index: linux-pm/drivers/acpi/scan.c > =================================================================== > --- linux-pm.orig/drivers/acpi/scan.c > +++ linux-pm/drivers/acpi/scan.c > @@ -657,16 +652,12 @@ static int acpi_tie_acpi_dev(struct acpi > return 0; > } > > -int acpi_device_add(struct acpi_device *device, > - void (*release)(struct device *)) > +int __acpi_device_add(struct acpi_device *device, > + void (*release)(struct device *)) > { > struct acpi_device_bus_id *acpi_device_bus_id; > int result; > > - result = acpi_tie_acpi_dev(device); > - if (result) > - return result; > - > /* > * Linkage > * ------- > @@ -755,6 +746,17 @@ err_unlock: > return result; > } > > +int acpi_device_add(struct acpi_device *adev, void (*release)(struct device *)) > +{ > + int ret; > + > + ret = acpi_tie_acpi_dev(adev); > + if (ret) > + return ret; > + > + return __acpi_device_add(adev, release); > +} > + > /* -------------------------------------------------------------------------- > Device Enumeration > -------------------------------------------------------------------------- */ > @@ -1681,14 +1683,10 @@ static void acpi_scan_dep_init(struct ac > { > struct acpi_dep_data *dep; > > - mutex_lock(&acpi_dep_list_lock); > - > list_for_each_entry(dep, &acpi_dep_list, node) { > if (dep->consumer == adev->handle) > adev->dep_unmet++; > } > - > - mutex_unlock(&acpi_dep_list_lock); > } > > void acpi_device_add_finalize(struct acpi_device *device) > @@ -1707,6 +1705,7 @@ static int acpi_add_single_object(struct > acpi_handle handle, int type, bool dep_init) > { > struct acpi_device *device; > + bool release_dep_lock = false; > int result; > > device = kzalloc(sizeof(struct acpi_device), GFP_KERNEL); > @@ -1720,16 +1719,31 @@ static int acpi_add_single_object(struct > * this must be done before the get power-/wakeup_dev-flags calls. > */ > if (type == ACPI_BUS_TYPE_DEVICE || type == ACPI_BUS_TYPE_PROCESSOR) { > - if (dep_init) > + if (dep_init) { > + mutex_lock(&acpi_dep_list_lock); > + /* > + * Hold the lock until the acpi_tie_acpi_dev() call > + * below to prevent concurrent acpi_scan_clear_dep() > + * from deleting a dependency list entry without > + * updating dep_unmet for the device. > + */ > + release_dep_lock = true; > acpi_scan_dep_init(device); > - > + } > acpi_scan_init_status(device); > } > > acpi_bus_get_power_flags(device); > acpi_bus_get_wakeup_device_flags(device); > > - result = acpi_device_add(device, acpi_device_release); > + result = acpi_tie_acpi_dev(device); > + > + if (release_dep_lock) > + mutex_unlock(&acpi_dep_list_lock); > + > + if (!result) > + result = __acpi_device_add(device, acpi_device_release); > + > if (result) { > acpi_device_release(&device->dev); > return result; > > >
Index: linux-pm/drivers/acpi/scan.c =================================================================== --- linux-pm.orig/drivers/acpi/scan.c +++ linux-pm/drivers/acpi/scan.c @@ -657,16 +652,12 @@ static int acpi_tie_acpi_dev(struct acpi return 0; } -int acpi_device_add(struct acpi_device *device, - void (*release)(struct device *)) +int __acpi_device_add(struct acpi_device *device, + void (*release)(struct device *)) { struct acpi_device_bus_id *acpi_device_bus_id; int result; - result = acpi_tie_acpi_dev(device); - if (result) - return result; - /* * Linkage * ------- @@ -755,6 +746,17 @@ err_unlock: return result; } +int acpi_device_add(struct acpi_device *adev, void (*release)(struct device *)) +{ + int ret; + + ret = acpi_tie_acpi_dev(adev); + if (ret) + return ret; + + return __acpi_device_add(adev, release); +} + /* -------------------------------------------------------------------------- Device Enumeration -------------------------------------------------------------------------- */ @@ -1681,14 +1683,10 @@ static void acpi_scan_dep_init(struct ac { struct acpi_dep_data *dep; - mutex_lock(&acpi_dep_list_lock); - list_for_each_entry(dep, &acpi_dep_list, node) { if (dep->consumer == adev->handle) adev->dep_unmet++; } - - mutex_unlock(&acpi_dep_list_lock); } void acpi_device_add_finalize(struct acpi_device *device) @@ -1707,6 +1705,7 @@ static int acpi_add_single_object(struct acpi_handle handle, int type, bool dep_init) { struct acpi_device *device; + bool release_dep_lock = false; int result; device = kzalloc(sizeof(struct acpi_device), GFP_KERNEL); @@ -1720,16 +1719,31 @@ static int acpi_add_single_object(struct * this must be done before the get power-/wakeup_dev-flags calls. */ if (type == ACPI_BUS_TYPE_DEVICE || type == ACPI_BUS_TYPE_PROCESSOR) { - if (dep_init) + if (dep_init) { + mutex_lock(&acpi_dep_list_lock); + /* + * Hold the lock until the acpi_tie_acpi_dev() call + * below to prevent concurrent acpi_scan_clear_dep() + * from deleting a dependency list entry without + * updating dep_unmet for the device. + */ + release_dep_lock = true; acpi_scan_dep_init(device); - + } acpi_scan_init_status(device); } acpi_bus_get_power_flags(device); acpi_bus_get_wakeup_device_flags(device); - result = acpi_device_add(device, acpi_device_release); + result = acpi_tie_acpi_dev(device); + + if (release_dep_lock) + mutex_unlock(&acpi_dep_list_lock); + + if (!result) + result = __acpi_device_add(device, acpi_device_release); + if (result) { acpi_device_release(&device->dev); return result;