[PATCH v4 0/5] ata: Do not release the host resources twice on probe() failure

[PATCH v4 0/5] ata: Do not release the host resources twice on probe() failure

[Niklas Cassel]

ata_host_start() registers ata_host_stop() as a devres action as soon as
it has succeeded:

	if (have_stop) {
		start_dr = devres_alloc(ata_host_stop, 0, GFP_KERNEL);
	...
	if (start_dr)
		devres_add(host->dev, start_dr);
	host->flags |= ATA_HOST_STARTED;

From that point on, releasing the host resources is owned by devres: when
probe() fails, the driver core calls devres_release_all(), which calls
ata_host_stop(), which calls ->port_stop() and ->host_stop().

ata_host_activate() and ahci_host_activate_multi_irqs() can however fail
after ata_host_start() has succeeded - devm_kasprintf(),
devm_request_irq() (a shared IRQ conflict) and ata_host_register()
(scsi_add_host(), ata_tport_add()) can all fail - and they return the
error with the devres action still registered. Since the caller cannot
tell whether ata_host_start() succeeded, and since it has to release the
resources for the failures happening before that, all the ahci-platform
drivers release the host resources in their probe() error path, e.g.
ahci_probe() calls ahci_platform_disable_resources() while
ahci_host_stop() does the same through devres.

The clocks, regulators, resets and PHYs of the host are therefore
released twice, which gives refcount underflow warnings from the clk,
regulator and phy cores and, for shared resources, can disable resources
which are still in use by other devices.

Patch 4 adds ata_host_undo_start(), which stops the ports and drops the
devres action without calling ->host_stop(), and calls it from both
activation helpers when they fail, so that "on failure, the caller
releases what it acquired" holds for all of them. sata_qstor and sata_fsl
are the only drivers which implement ->host_stop() while having no error
handling at all for the activate host call, so they get some.

Patches 1 to 3 have to come first, as they fix error paths which patch 4
would otherwise turn into resource leaks, and which are worth fixing on
their own:

- ahci_st is the only ahci-platform driver whose ->host_stop() does more
  than its probe() error path, as it also asserts the "pwr-dwn" reset
  (patch 1).
- sata_fsl releases hcr_base and host_priv in its probe() error path
  although sata_fsl_host_stop() does that as well, which is a
  use-after-free that the two device_create_file() calls after
  ata_host_activate() can trigger today (patch 2).
- ahci_host_activate_multi_irqs() never frees the IRQs which it
  requested when it fails, so the IRQ handlers stay registered while the
  caller releases the resources of the host (patch 3).

Patch 5 is an unrelated kdoc fix that I noticed while documenting the
above.

Changes since v3:
- New patch 2, which fixes the use-after-free of host_priv in the
  probe() error path of sata_fsl. Patch 4 would otherwise make sata_fsl
  leak hcr_base and host_priv when activating the host fails.
- New patch 3, which frees the IRQs requested by
  ahci_host_activate_multi_irqs() when it fails, like
  ata_host_activate() already does.
- Reword the "if failed, just free the IRQ and leave ports alone"
  comment in ata_host_activate(), as the ports are no longer left alone.

Niklas Cassel (5):
  ata: ahci_st: Assert the power down reset in the probe() error path
  ata: sata_fsl: Fix use-after-free of host_priv on probe() failure
  ata: libahci: Free the IRQs when activating a multi-IRQ host fails
  ata: libata: Do not leave ata_host_stop() registered when activation
    fails
  ata: libata-core: Fix the ata_host_register() kdoc

 drivers/ata/ahci_st.c          | 51 ++++++++++++---------
 drivers/ata/libahci.c          | 28 +++++++++++-
 drivers/ata/libahci_platform.c |  4 ++
 drivers/ata/libata-core.c      | 81 ++++++++++++++++++++++++++++++----
 drivers/ata/libata-sff.c       |  5 +++
 drivers/ata/sata_fsl.c         | 24 +++++++---
 drivers/ata/sata_qstor.c       |  8 +++-
 include/linux/libata.h         |  1 +
 8 files changed, 161 insertions(+), 41 deletions(-)

-- 
2.55.0

[PATCH v4 1/5] ata: ahci_st: Assert the power down reset in the probe() error path

[Niklas Cassel]

st_ahci_probe_resets() deasserts the "pwr-dwn" reset, but the probe()
error path of st_ahci_probe() only releases the host resources, so the
SATA IP is left powered up when probe() fails after
st_ahci_probe_resets() has succeeded, e.g. when
ahci_platform_enable_resources() fails.

The reset is asserted by st_ahci_host_stop(), however ->host_stop() is
only called through the ata_host_stop() devres action registered by
ata_host_start(), so it does not cover any failure happening before the
host has been started.

Factor the assert out into st_ahci_assert_pwrdwn() and call it from both
probe() error paths. The "pwr-dwn" reset control is an exclusive one, so
asserting it once more from st_ahci_host_stop() is harmless.

No functional change intended for ->host_stop() and st_ahci_suspend().

Fixes: 76884cb2f7da ("ahci: st: Add support for ST's SATA IP")
Cc: stable@vger.kernel.org
Signed-off-by: Niklas Cassel <cassel@kernel.org>
---
 drivers/ata/ahci_st.c | 51 +++++++++++++++++++++++++------------------
 1 file changed, 30 insertions(+), 21 deletions(-)

diff --git a/drivers/ata/ahci_st.c b/drivers/ata/ahci_st.c
index 4336c8a6e208..39ebedf93344 100644
--- a/drivers/ata/ahci_st.c
+++ b/drivers/ata/ahci_st.c
@@ -83,18 +83,27 @@ static int st_ahci_deassert_resets(struct ahci_host_priv *hpriv,
 	return 0;
 }
 
-static void st_ahci_host_stop(struct ata_host *host)
+static int st_ahci_assert_pwrdwn(struct ahci_host_priv *hpriv,
+				 struct device *dev)
 {
-	struct ahci_host_priv *hpriv = host->private_data;
 	struct st_ahci_drv_data *drv_data = hpriv->plat_data;
-	struct device *dev = host->dev;
 	int err;
 
-	if (drv_data->pwr) {
-		err = reset_control_assert(drv_data->pwr);
-		if (err)
-			dev_err(dev, "unable to pwrdwn\n");
-	}
+	if (!drv_data->pwr)
+		return 0;
+
+	err = reset_control_assert(drv_data->pwr);
+	if (err)
+		dev_err(dev, "unable to pwrdwn\n");
+
+	return err;
+}
+
+static void st_ahci_host_stop(struct ata_host *host)
+{
+	struct ahci_host_priv *hpriv = host->private_data;
+
+	st_ahci_assert_pwrdwn(hpriv, host->dev);
 
 	ahci_platform_disable_resources(hpriv);
 }
@@ -162,38 +171,38 @@ static int st_ahci_probe(struct platform_device *pdev)
 
 	err = ahci_platform_enable_resources(hpriv);
 	if (err)
-		return err;
+		goto assert_pwrdwn;
 
 	st_ahci_configure_oob(hpriv->mmio);
 
 	err = ahci_platform_init_host(pdev, hpriv, &st_ahci_port_info,
 				      &ahci_platform_sht);
-	if (err) {
-		ahci_platform_disable_resources(hpriv);
-		return err;
-	}
+	if (err)
+		goto disable_resources;
 
 	return 0;
+
+disable_resources:
+	ahci_platform_disable_resources(hpriv);
+assert_pwrdwn:
+	st_ahci_assert_pwrdwn(hpriv, &pdev->dev);
+
+	return err;
 }
 
 static int st_ahci_suspend(struct device *dev)
 {
 	struct ata_host *host = dev_get_drvdata(dev);
 	struct ahci_host_priv *hpriv = host->private_data;
-	struct st_ahci_drv_data *drv_data = hpriv->plat_data;
 	int err;
 
 	err = ahci_platform_suspend_host(dev);
 	if (err)
 		return err;
 
-	if (drv_data->pwr) {
-		err = reset_control_assert(drv_data->pwr);
-		if (err) {
-			dev_err(dev, "unable to pwrdwn");
-			return err;
-		}
-	}
+	err = st_ahci_assert_pwrdwn(hpriv, dev);
+	if (err)
+		return err;
 
 	ahci_platform_disable_resources(hpriv);
 
-- 
2.55.0

Re: [PATCH v4 1/5] ata: ahci_st: Assert the power down reset in the probe() error path

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] st_ahci_probe_resets() blindly masks all errors from devm_reset_control_get(), breaking probe deferral and leading to kernel panics.
--

commit aedfb0423cffc301a78c793e7a81df6e88c712e0
Author: Niklas Cassel <cassel@kernel.org>

ata: ahci_st: Assert the power down reset in the probe() error path

This commit updates the probe error path and host stop functions in the
ahci_st driver to properly assert the power down reset. It extracts the reset
assertion logic into a helper function and ensures the SATA IP is not left
powered up if initialization fails after resets are deasserted.

> diff --git a/drivers/ata/ahci_st.c b/drivers/ata/ahci_st.c
> index 4336c8a6e2087..39ebedf93344d 100644
> --- a/drivers/ata/ahci_st.c
> +++ b/drivers/ata/ahci_st.c
[ ... ]
> @@ -162,38 +171,38 @@ static int st_ahci_probe(struct platform_device *pdev)
>  
>  	err = ahci_platform_enable_resources(hpriv);
>  	if (err)
> -		return err;
> +		goto assert_pwrdwn;

[Severity: High]
This isn't a bug introduced by this patch, but while reviewing the probe path
here, I noticed a pre-existing issue in st_ahci_probe_resets(), which
executes just before ahci_platform_enable_resources().

Does st_ahci_probe_resets() blindly mask all errors from
devm_reset_control_get(), breaking probe deferral?

drivers/ata/ahci_st.c:st_ahci_probe_resets() {
    ...
    drv_data->pwr = devm_reset_control_get(dev, "pwr-dwn");
    if (IS_ERR(drv_data->pwr)) {
        dev_info(dev, "power reset control not defined\n");
        drv_data->pwr = NULL;
    }
    ...
}

If the reset controller driver probes after the SATA driver,
devm_reset_control_get() returns -EPROBE_DEFER.  Because the code treats this
as a missing optional reset, it continues initialization.

Will this cause an imprecise external abort (kernel panic) when
st_ahci_configure_oob() subsequently attempts to access the MMIO registers of
a hardware block that is still held in reset?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260910171406.131211-7-cassel@kernel.org?part=1

Re: [PATCH v4 1/5] ata: ahci_st: Assert the power down reset in the probe() error path

[Niklas Cassel]

On Thu, Sep 10, 2026 at 05:29:03PM +0000, sashiko-bot@kernel.org wrote:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> 
> Pre-existing issues:
> - [High] st_ahci_probe_resets() blindly masks all errors from devm_reset_control_get(), breaking probe deferral and leading to kernel panics.

I do not intend to fix this pre-existing issue.

Would be happy to pick up a patch for it though.


Kind regards,
Niklas

[PATCH v4 2/5] ata: sata_fsl: Fix use-after-free of host_priv on probe() failure

[Niklas Cassel]

sata_fsl_host_stop() releases hcr_base and host_priv:

	static void sata_fsl_host_stop(struct ata_host *host)
	{
		struct sata_fsl_host_priv *host_priv = host->private_data;

		iounmap(host_priv->hcr_base);
		kfree(host_priv);
	}

->host_stop() is called by the driver core through the ata_host_stop()
devres action which ata_host_start() registers, so it is called both
when the device is unbound and when probe() fails after
ata_host_activate() has started the host.

The error_exit_with_cleanup label in sata_fsl_probe() releases hcr_base
and host_priv as well, and it is reachable from the two
device_create_file() calls done after ata_host_activate(). In that case
sata_fsl_host_stop() runs on an already freed host_priv, resulting in a
use-after-free and a double iounmap()/kfree().

sata_fsl_probe() also ignores the return value of ata_host_activate(),
so probe() returns success even if activating the host failed.

Check the return value of ata_host_activate() and, once the host has
been activated, leave hcr_base and host_priv to sata_fsl_host_stop().

Note that if ata_host_activate() fails inside ata_host_start(), e.g. if
sata_fsl_port_start() fails, ->host_stop() is not registered and
hcr_base and host_priv are leaked. Leaking them is preferable to freeing
them twice, and this is addressed by a later patch in this series.

Fixes: 6c8ad7e8cf29 ("sata_fsl: fix UAF in sata_fsl_port_stop when rmmod sata_fsl")
Cc: stable@vger.kernel.org
Signed-off-by: Niklas Cassel <cassel@kernel.org>
---
 drivers/ata/sata_fsl.c | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/drivers/ata/sata_fsl.c b/drivers/ata/sata_fsl.c
index 70b210afd291..2123da66dc3c 100644
--- a/drivers/ata/sata_fsl.c
+++ b/drivers/ata/sata_fsl.c
@@ -1490,8 +1490,10 @@ static int sata_fsl_probe(struct platform_device *ofdev)
 	 * device discovery process, invoking our port_start() handler &
 	 * error_handler() to execute a dummy Softreset EH session
 	 */
-	ata_host_activate(host, irq, sata_fsl_interrupt, SATA_FSL_IRQ_FLAG,
-			  &sata_fsl_sht);
+	retval = ata_host_activate(host, irq, sata_fsl_interrupt,
+				   SATA_FSL_IRQ_FLAG, &sata_fsl_sht);
+	if (retval)
+		return retval;
 
 	host_priv->intr_coalescing.show = fsl_sata_intr_coalescing_show;
 	host_priv->intr_coalescing.store = fsl_sata_intr_coalescing_store;
@@ -1500,7 +1502,7 @@ static int sata_fsl_probe(struct platform_device *ofdev)
 	host_priv->intr_coalescing.attr.mode = S_IRUGO | S_IWUSR;
 	retval = device_create_file(host->dev, &host_priv->intr_coalescing);
 	if (retval)
-		goto error_exit_with_cleanup;
+		goto error_exit_detach;
 
 	host_priv->rx_watermark.show = fsl_sata_rx_watermark_show;
 	host_priv->rx_watermark.store = fsl_sata_rx_watermark_store;
@@ -1510,16 +1512,24 @@ static int sata_fsl_probe(struct platform_device *ofdev)
 	retval = device_create_file(host->dev, &host_priv->rx_watermark);
 	if (retval) {
 		device_remove_file(&ofdev->dev, &host_priv->intr_coalescing);
-		goto error_exit_with_cleanup;
+		goto error_exit_detach;
 	}
 
 	return 0;
 
-error_exit_with_cleanup:
+	/*
+	 * Once the host has been activated, hcr_base and host_priv are
+	 * released by sata_fsl_host_stop(), which is called by the driver core
+	 * through the ata_host_stop() devres action registered by
+	 * ata_host_start(). Releasing them here as well would result in a
+	 * double iounmap() and a use-after-free.
+	 */
+error_exit_detach:
+	ata_host_detach(host);
 
-	if (host)
-		ata_host_detach(host);
+	return retval;
 
+error_exit_with_cleanup:
 	if (hcr_base)
 		iounmap(hcr_base);
 	kfree(host_priv);
-- 
2.55.0

[PATCH v4 3/5] ata: libahci: Free the IRQs when activating a multi-IRQ host fails

[Niklas Cassel]

ahci_host_activate_multi_irqs() requests one IRQ per port, but it does
not free them when requesting one of them, or when registering the host,
fails. The IRQs are only freed by the driver core, when it releases the
devres of the device after probe() has returned, while the caller of
ahci_host_activate() releases the resources of the host in its probe()
error path, e.g. ahci_probe() disables the clocks, regulators, resets and
PHYs of the host. An IRQ handler running in that window would access the
MMIO of a host which is no longer clocked.

ahci_host_activate_multi_irqs() did free the IRQs until commit
0a142b26921c ("ahci: cleanup ahci_host_activate_multi_irqs"), which
removed the explicit free because devm makes it unnecessary. That is true
for freeing the IRQs as such, but not for the window described above:
devres is only released after probe() has returned, i.e. after the error
path of the caller has released the resources of the host.

Note that this window cannot be hit with the current users: the only user
of AHCI_HFLAG_MULTI_MSI is the AHCI PCI driver, which does not release
any resource in its probe() error path, and the ports of the host are
still frozen, i.e. their interrupts are masked, when ata_host_register()
fails.

Free the IRQs explicitly again, like ata_host_activate() does, so that
the IRQ handlers cannot run once ahci_host_activate() has failed.

Fixes: 0a142b26921c ("ahci: cleanup ahci_host_activate_multi_irqs")
Cc: stable@vger.kernel.org
Signed-off-by: Niklas Cassel <cassel@kernel.org>
---
 drivers/ata/libahci.c | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index 6d72eb017b49..9f479daa89b0 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -2723,11 +2723,33 @@ static int ahci_host_activate_multi_irqs(struct ata_host *host,
 				0, pp->irq_desc, host->ports[i]);
 
 		if (rc)
-			return rc;
+			goto free_irqs;
 		ata_port_desc_misc(host->ports[i], irq);
 	}
 
-	return ata_host_register(host, sht);
+	rc = ata_host_register(host, sht);
+	if (rc)
+		goto free_irqs;
+
+	return 0;
+
+free_irqs:
+	/*
+	 * Free the IRQs which have been requested, so that the handlers can no
+	 * longer access the MMIO of the host once we return, e.g. after the
+	 * caller has disabled the clocks of the host.
+	 */
+	while (--i >= 0) {
+		struct ahci_port_priv *pp = host->ports[i]->private_data;
+
+		if (!pp)
+			continue;
+
+		devm_free_irq(host->dev, hpriv->get_irq_vector(host, i),
+			      host->ports[i]);
+	}
+
+	return rc;
 }
 
 /**
-- 
2.55.0

[PATCH v4 4/5] ata: libata: Do not leave ata_host_stop() registered when activation fails

[Niklas Cassel]

ata_host_start() registers ata_host_stop() as a devres action as soon as
it has succeeded, which hands the release of the host resources over to
devres: ->port_stop() and ->host_stop() are then called by the driver
core when probe() fails.

ata_host_activate() and ahci_host_activate_multi_irqs() can both fail
after ata_host_start() has succeeded, e.g. if devm_request_irq() or
ata_host_register() fails, and they return the error with the devres
action still registered. A driver which releases the host resources in
its probe() error path therefore releases them twice: once itself and
once through ->host_stop().

All ahci-platform drivers are in that situation, e.g. ahci_probe() calls
ahci_platform_disable_resources() while ahci_host_stop() does the same
through devres. This gives refcount underflow warnings from the clk,
regulator and phy cores and, for shared resources, can disable resources
which are still in use by other devices.

Add ata_host_undo_start(), which stops the ports and drops the devres
action without calling ->host_stop(), and call it from both activation
helpers when they fail. Releasing the host resources on failure is then
always left to the caller, which is what all callers having a probe()
error path already assume.

This changes the semantics for the drivers which implement ->host_stop()
while also completely lacking error handling for the activate host call.
Add activate host error handling for sata_qstor and sata_fsl.

Note that ata_pci_sff_activate_host() is deliberately left as is: none of
its callers releases the host resources in its probe() error path, they
all rely on ->host_stop() being called by devres, including
ata_pci_init_one(), which releases the devres group of the host itself.

Fixes: 1896b15eddb4 ("ahci_platform: perform platform exit in host_stop() hook")
Cc: stable@vger.kernel.org
Signed-off-by: Niklas Cassel <cassel@kernel.org>
---
 drivers/ata/libahci.c          |  2 +
 drivers/ata/libahci_platform.c |  4 ++
 drivers/ata/libata-core.c      | 75 +++++++++++++++++++++++++++++++---
 drivers/ata/libata-sff.c       |  5 +++
 drivers/ata/sata_fsl.c         |  2 +-
 drivers/ata/sata_qstor.c       |  8 +++-
 include/linux/libata.h         |  1 +
 7 files changed, 88 insertions(+), 9 deletions(-)

diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index 9f479daa89b0..27d1b2197868 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -2749,6 +2749,8 @@ static int ahci_host_activate_multi_irqs(struct ata_host *host,
 			      host->ports[i]);
 	}
 
+	ata_host_undo_start(host);
+
 	return rc;
 }
 
diff --git a/drivers/ata/libahci_platform.c b/drivers/ata/libahci_platform.c
index 6e072d681341..b44c0db4a86e 100644
--- a/drivers/ata/libahci_platform.c
+++ b/drivers/ata/libahci_platform.c
@@ -689,6 +689,10 @@ EXPORT_SYMBOL_GPL(ahci_platform_get_resources);
  * ahci-platform host, note any necessary resources (ie clks, phys, etc.)
  * must be initialized / enabled before calling this.
  *
+ * On failure, ->host_stop() is not called, so the caller has to release the
+ * resources it enabled (clocks, regulators, resets, PHYs) in its probe()
+ * error path.
+ *
  * RETURNS:
  * 0 on success otherwise a negative error code
  */
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index f482c0a6d7e9..197f5d6e93ce 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -6127,6 +6127,46 @@ int ata_host_start(struct ata_host *host)
 }
 EXPORT_SYMBOL_GPL(ata_host_start);
 
+/**
+ *	ata_host_undo_start - undo ata_host_start()
+ *	@host: ATA host to undo_start
+ *
+ *	Stop the ports of @host and drop the devres action registered by
+ *	ata_host_start(), without calling ->host_stop().  Nothing is done if
+ *	@host has not been started.
+ *
+ *	This gives the release of the host resources back to the caller, which
+ *	is what a driver whose probe() error path releases those resources
+ *	itself needs when starting or activating the host fails.
+ *
+ *	LOCKING:
+ *	Inherited from calling layer (may sleep).
+ */
+void ata_host_undo_start(struct ata_host *host)
+{
+	int i;
+
+	if (!(host->flags & ATA_HOST_STARTED))
+		return;
+
+	for (i = 0; i < host->n_ports; i++) {
+		struct ata_port *ap = host->ports[i];
+
+		if (ap->ops->port_stop)
+			ap->ops->port_stop(ap);
+	}
+
+	/*
+	 * Drop the action added by ata_host_start() without calling it.
+	 * It does not exist if neither ->port_stop() nor ->host_stop() is
+	 * implemented, in which case there is nothing to drop.
+	 */
+	devres_destroy(host->dev, ata_host_stop, NULL, NULL);
+
+	host->flags &= ~ATA_HOST_STARTED;
+}
+EXPORT_SYMBOL_GPL(ata_host_undo_start);
+
 /**
  *	ata_host_init - Initialize a host struct for sas (ipr, libsas)
  *	@host:	host to initialize
@@ -6201,6 +6241,12 @@ static void async_port_probe(void *data, async_cookie_t cookie)
  *	starts ports, registers @host with ATA and SCSI layers and
  *	probe registered devices.
  *
+ *	On failure, the host remains started, i.e. the devres action
+ *	registered by ata_host_start() is kept, so ->host_stop() is called by
+ *	the driver core when probe() fails.  A caller which releases the host
+ *	resources in its own probe() error path must therefore call
+ *	ata_host_undo_start().
+ *
  *	LOCKING:
  *	Inherited from calling layer (may sleep).
  *
@@ -6294,6 +6340,10 @@ EXPORT_SYMBOL_GPL(ata_host_register);
  *	have set polling mode on the port. In this case, @irq_handler
  *	should be NULL.
  *
+ *	On failure, the ports are stopped again and the devres action
+ *	registered by ata_host_start() is dropped without calling
+ *	->host_stop(), so releasing the host resources is left to the caller.
+ *
  *	LOCKING:
  *	Inherited from calling layer (may sleep).
  *
@@ -6314,27 +6364,40 @@ int ata_host_activate(struct ata_host *host, int irq,
 	/* Special case for polling mode */
 	if (!irq) {
 		WARN_ON(irq_handler);
-		return ata_host_register(host, sht);
+		rc = ata_host_register(host, sht);
+		if (rc)
+			goto undo_start;
+
+		return 0;
 	}
 
 	irq_desc = devm_kasprintf(host->dev, GFP_KERNEL, "%s[%s]",
 				  dev_driver_string(host->dev),
 				  dev_name(host->dev));
-	if (!irq_desc)
-		return -ENOMEM;
+	if (!irq_desc) {
+		rc = -ENOMEM;
+		goto undo_start;
+	}
 
 	rc = devm_request_irq(host->dev, irq, irq_handler, irq_flags,
 			      irq_desc, host);
 	if (rc)
-		return rc;
+		goto undo_start;
 
 	for (i = 0; i < host->n_ports; i++)
 		ata_port_desc_misc(host->ports[i], irq);
 
 	rc = ata_host_register(host, sht);
-	/* if failed, just free the IRQ and leave ports alone */
-	if (rc)
+	if (rc) {
+		/* Free the IRQ, so that the handler can no longer run */
 		devm_free_irq(host->dev, irq, host);
+		goto undo_start;
+	}
+
+	return 0;
+
+undo_start:
+	ata_host_undo_start(host);
 
 	return rc;
 }
diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c
index 976e4e160494..d5ef0338735c 100644
--- a/drivers/ata/libata-sff.c
+++ b/drivers/ata/libata-sff.c
@@ -2267,6 +2267,11 @@ EXPORT_SYMBOL_GPL(ata_pci_sff_prepare_host);
  *	hosts.  This separate helper is necessary because SFF hosts
  *	use two separate interrupts in legacy mode.
  *
+ *	Note that, unlike ata_host_activate(), the devres action registered
+ *	by ata_host_start() is kept on failure, i.e. ->host_stop() is called
+ *	by the driver core when probe() fails.  All callers of this function
+ *	rely on that, none of them releases the host resources itself.
+ *
  *	LOCKING:
  *	Inherited from calling layer (may sleep).
  *
diff --git a/drivers/ata/sata_fsl.c b/drivers/ata/sata_fsl.c
index 2123da66dc3c..2141a2189b5e 100644
--- a/drivers/ata/sata_fsl.c
+++ b/drivers/ata/sata_fsl.c
@@ -1493,7 +1493,7 @@ static int sata_fsl_probe(struct platform_device *ofdev)
 	retval = ata_host_activate(host, irq, sata_fsl_interrupt,
 				   SATA_FSL_IRQ_FLAG, &sata_fsl_sht);
 	if (retval)
-		return retval;
+		goto error_exit_with_cleanup;
 
 	host_priv->intr_coalescing.show = fsl_sata_intr_coalescing_show;
 	host_priv->intr_coalescing.store = fsl_sata_intr_coalescing_store;
diff --git a/drivers/ata/sata_qstor.c b/drivers/ata/sata_qstor.c
index 4e7f5b2ff3f6..f38310b84f51 100644
--- a/drivers/ata/sata_qstor.c
+++ b/drivers/ata/sata_qstor.c
@@ -584,8 +584,12 @@ static int qs_ata_init_one(struct pci_dev *pdev,
 	qs_host_init(host, board_idx);
 
 	pci_set_master(pdev);
-	return ata_host_activate(host, pdev->irq, qs_intr, IRQF_SHARED,
-				 &qs_ata_sht);
+	rc = ata_host_activate(host, pdev->irq, qs_intr, IRQF_SHARED,
+			       &qs_ata_sht);
+	if (rc)
+		qs_host_stop(host);
+
+	return rc;
 }
 
 module_pci_driver(qs_ata_pci_driver);
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 313e96173b19..b1debcef4947 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -1147,6 +1147,7 @@ extern struct ata_host *ata_host_alloc_pinfo(struct device *dev,
 extern void ata_host_get(struct ata_host *host);
 extern void ata_host_put(struct ata_host *host);
 extern int ata_host_start(struct ata_host *host);
+extern void ata_host_undo_start(struct ata_host *host);
 extern int ata_host_register(struct ata_host *host,
 			     const struct scsi_host_template *sht);
 extern int ata_host_activate(struct ata_host *host, int irq,
-- 
2.55.0

[PATCH v4 5/5] ata: libata-core: Fix the ata_host_register() kdoc

[Niklas Cassel]

ata_host_register() does not start the ports of the host, it requires
them to have been started already:

	/* host must have been started */
	if (!(host->flags & ATA_HOST_STARTED)) {
		dev_err(host->dev, "BUG: trying to register unstarted host\n");
		WARN_ON(1);
		return -EINVAL;
	}

Fix the kdoc accordingly, and fix the grammar of the last sentence while
at it.

Signed-off-by: Niklas Cassel <cassel@kernel.org>
---
 drivers/ata/libata-core.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 197f5d6e93ce..682c58889715 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -6237,9 +6237,9 @@ static void async_port_probe(void *data, async_cookie_t cookie)
  *	@sht: template for SCSI host
  *
  *	Register initialized ATA host.  @host is allocated using
- *	ata_host_alloc() and fully initialized by LLD.  This function
- *	starts ports, registers @host with ATA and SCSI layers and
- *	probe registered devices.
+ *	ata_host_alloc(), fully initialized by the LLD and started using
+ *	ata_host_start().  This function registers @host with the ATA and
+ *	SCSI layers and probes the registered devices.
  *
  *	On failure, the host remains started, i.e. the devres action
  *	registered by ata_host_start() is kept, so ->host_stop() is called by
-- 
2.55.0