Commit 130f4caf145c ("libata: Ensure ata_port probe has completed before
detach") may cause system freeze during suspend.
Using async_synchronize_full() in PM callbacks is wrong, since async
callbacks that are already scheduled may wait for not-yet-scheduled
callbacks, causes a circular dependency.
Instead of using big hammer like async_synchronize_full(), use async
cookie to make sure port probe are synced, without affecting other
scheduled PM callbacks.
Fixes: 130f4caf145c ("libata: Ensure ata_port probe has completed before detach")
BugLink: https://bugs.launchpad.net/bugs/1867983
Suggested-by: John Garry <[email protected]>
Signed-off-by: Kai-Heng Feng <[email protected]>
---
v3:
- Move the comment to properly align with the code.
v2:
- Sync up to cookie + 1.
- Squash the synchronization into the same loop.
drivers/ata/libata-core.c | 11 +++++------
include/linux/libata.h | 3 +++
2 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 69361ec43db5..b1cd4d97bc2a 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -42,7 +42,6 @@
#include <linux/workqueue.h>
#include <linux/scatterlist.h>
#include <linux/io.h>
-#include <linux/async.h>
#include <linux/log2.h>
#include <linux/slab.h>
#include <linux/glob.h>
@@ -5778,7 +5777,7 @@ int ata_host_register(struct ata_host *host, struct scsi_host_template *sht)
/* perform each probe asynchronously */
for (i = 0; i < host->n_ports; i++) {
struct ata_port *ap = host->ports[i];
- async_schedule(async_port_probe, ap);
+ ap->cookie = async_schedule(async_port_probe, ap);
}
return 0;
@@ -5920,11 +5919,11 @@ void ata_host_detach(struct ata_host *host)
{
int i;
- /* Ensure ata_port probe has completed */
- async_synchronize_full();
-
- for (i = 0; i < host->n_ports; i++)
+ for (i = 0; i < host->n_ports; i++) {
+ /* Ensure ata_port probe has completed */
+ async_synchronize_cookie(host->ports[i]->cookie + 1);
ata_port_detach(host->ports[i]);
+ }
/* the host is dead now, dissociate ACPI */
ata_acpi_dissociate(host);
diff --git a/include/linux/libata.h b/include/linux/libata.h
index af832852e620..8a4843704d28 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -22,6 +22,7 @@
#include <linux/acpi.h>
#include <linux/cdrom.h>
#include <linux/sched.h>
+#include <linux/async.h>
/*
* Define if arch has non-standard setup. This is a _PCI_ standard
@@ -872,6 +873,8 @@ struct ata_port {
struct timer_list fastdrain_timer;
unsigned long fastdrain_cnt;
+ async_cookie_t cookie;
+
int em_message_type;
void *private_data;
--
2.17.1
On 03/06/2020 08:48, Kai-Heng Feng wrote:
> Commit 130f4caf145c ("libata: Ensure ata_port probe has completed before
> detach") may cause system freeze during suspend.
>
> Using async_synchronize_full() in PM callbacks is wrong, since async
> callbacks that are already scheduled may wait for not-yet-scheduled
> callbacks, causes a circular dependency.
>
> Instead of using big hammer like async_synchronize_full(), use async
> cookie to make sure port probe are synced, without affecting other
> scheduled PM callbacks.
>
> Fixes: 130f4caf145c ("libata: Ensure ata_port probe has completed before detach")
> BugLink: https://bugs.launchpad.net/bugs/1867983
> Suggested-by: John Garry <[email protected]>
> Signed-off-by: Kai-Heng Feng <[email protected]>
thanks,
Tested-by: John Garry <[email protected]>
> ---
> v3:
> - Move the comment to properly align with the code.
>
> v2:
> - Sync up to cookie + 1.
> - Squash the synchronization into the same loop.
>
> drivers/ata/libata-core.c | 11 +++++------
> include/linux/libata.h | 3 +++
> 2 files changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
> index 69361ec43db5..b1cd4d97bc2a 100644
> --- a/drivers/ata/libata-core.c
> +++ b/drivers/ata/libata-core.c
> @@ -42,7 +42,6 @@
> #include <linux/workqueue.h>
> #include <linux/scatterlist.h>
> #include <linux/io.h>
> -#include <linux/async.h>
> #include <linux/log2.h>
> #include <linux/slab.h>
> #include <linux/glob.h>
> @@ -5778,7 +5777,7 @@ int ata_host_register(struct ata_host *host, struct scsi_host_template *sht)
> /* perform each probe asynchronously */
> for (i = 0; i < host->n_ports; i++) {
> struct ata_port *ap = host->ports[i];
> - async_schedule(async_port_probe, ap);
> + ap->cookie = async_schedule(async_port_probe, ap);
> }
>
> return 0;
> @@ -5920,11 +5919,11 @@ void ata_host_detach(struct ata_host *host)
> {
> int i;
>
> - /* Ensure ata_port probe has completed */
> - async_synchronize_full();
> -
> - for (i = 0; i < host->n_ports; i++)
> + for (i = 0; i < host->n_ports; i++) {
> + /* Ensure ata_port probe has completed */
> + async_synchronize_cookie(host->ports[i]->cookie + 1);
> ata_port_detach(host->ports[i]);
> + }
>
> /* the host is dead now, dissociate ACPI */
> ata_acpi_dissociate(host);
> diff --git a/include/linux/libata.h b/include/linux/libata.h
> index af832852e620..8a4843704d28 100644
> --- a/include/linux/libata.h
> +++ b/include/linux/libata.h
> @@ -22,6 +22,7 @@
> #include <linux/acpi.h>
> #include <linux/cdrom.h>
> #include <linux/sched.h>
> +#include <linux/async.h>
>
> /*
> * Define if arch has non-standard setup. This is a _PCI_ standard
> @@ -872,6 +873,8 @@ struct ata_port {
> struct timer_list fastdrain_timer;
> unsigned long fastdrain_cnt;
>
> + async_cookie_t cookie;
> +
> int em_message_type;
> void *private_data;
>
>
Hi Jens,
> On Jun 3, 2020, at 16:40, John Garry <[email protected]> wrote:
>
> On 03/06/2020 08:48, Kai-Heng Feng wrote:
>> Commit 130f4caf145c ("libata: Ensure ata_port probe has completed before
>> detach") may cause system freeze during suspend.
>> Using async_synchronize_full() in PM callbacks is wrong, since async
>> callbacks that are already scheduled may wait for not-yet-scheduled
>> callbacks, causes a circular dependency.
>> Instead of using big hammer like async_synchronize_full(), use async
>> cookie to make sure port probe are synced, without affecting other
>> scheduled PM callbacks.
>> Fixes: 130f4caf145c ("libata: Ensure ata_port probe has completed before detach")
>> BugLink: https://bugs.launchpad.net/bugs/1867983
>> Suggested-by: John Garry <[email protected]>
>> Signed-off-by: Kai-Heng Feng <[email protected]>
>
> thanks,
> Tested-by: John Garry <[email protected]>
Can you please review or merge this patch?
Kai-Heng
>
>> ---
>> v3:
>> - Move the comment to properly align with the code.
>> v2:
>> - Sync up to cookie + 1.
>> - Squash the synchronization into the same loop.
>> drivers/ata/libata-core.c | 11 +++++------
>> include/linux/libata.h | 3 +++
>> 2 files changed, 8 insertions(+), 6 deletions(-)
>> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
>> index 69361ec43db5..b1cd4d97bc2a 100644
>> --- a/drivers/ata/libata-core.c
>> +++ b/drivers/ata/libata-core.c
>> @@ -42,7 +42,6 @@
>> #include <linux/workqueue.h>
>> #include <linux/scatterlist.h>
>> #include <linux/io.h>
>> -#include <linux/async.h>
>> #include <linux/log2.h>
>> #include <linux/slab.h>
>> #include <linux/glob.h>
>> @@ -5778,7 +5777,7 @@ int ata_host_register(struct ata_host *host, struct scsi_host_template *sht)
>> /* perform each probe asynchronously */
>> for (i = 0; i < host->n_ports; i++) {
>> struct ata_port *ap = host->ports[i];
>> - async_schedule(async_port_probe, ap);
>> + ap->cookie = async_schedule(async_port_probe, ap);
>> }
>> return 0;
>> @@ -5920,11 +5919,11 @@ void ata_host_detach(struct ata_host *host)
>> {
>> int i;
>> - /* Ensure ata_port probe has completed */
>> - async_synchronize_full();
>> -
>> - for (i = 0; i < host->n_ports; i++)
>> + for (i = 0; i < host->n_ports; i++) {
>> + /* Ensure ata_port probe has completed */
>> + async_synchronize_cookie(host->ports[i]->cookie + 1);
>> ata_port_detach(host->ports[i]);
>> + }
>> /* the host is dead now, dissociate ACPI */
>> ata_acpi_dissociate(host);
>> diff --git a/include/linux/libata.h b/include/linux/libata.h
>> index af832852e620..8a4843704d28 100644
>> --- a/include/linux/libata.h
>> +++ b/include/linux/libata.h
>> @@ -22,6 +22,7 @@
>> #include <linux/acpi.h>
>> #include <linux/cdrom.h>
>> #include <linux/sched.h>
>> +#include <linux/async.h>
>> /*
>> * Define if arch has non-standard setup. This is a _PCI_ standard
>> @@ -872,6 +873,8 @@ struct ata_port {
>> struct timer_list fastdrain_timer;
>> unsigned long fastdrain_cnt;
>> + async_cookie_t cookie;
>> +
>> int em_message_type;
>> void *private_data;
>>
>
On 6/3/20 1:48 AM, Kai-Heng Feng wrote:
> Commit 130f4caf145c ("libata: Ensure ata_port probe has completed before
> detach") may cause system freeze during suspend.
>
> Using async_synchronize_full() in PM callbacks is wrong, since async
> callbacks that are already scheduled may wait for not-yet-scheduled
> callbacks, causes a circular dependency.
>
> Instead of using big hammer like async_synchronize_full(), use async
> cookie to make sure port probe are synced, without affecting other
> scheduled PM callbacks.
Queued up for 5.8, thanks.
--
Jens Axboe