arch/powerpc/platforms/pseries/rtas-fadump.c | 80 ++++++++++++-------- arch/powerpc/platforms/pseries/rtas-fadump.h | 6 ++ 2 files changed, 53 insertions(+), 33 deletions(-)
The ibm,configure-kernel-dump RTAS call sites in
rtas_fadump_register(), rtas_fadump_unregister(), and
rtas_fadump_invalidate() polled indefinitely while firmware returned
a busy status. A misbehaving or hung firmware could stall these paths
forever, blocking fadump registration at boot or preventing clean
teardown.
Introduce rtas_fadump_call(), a helper that wraps the common
busy-wait pattern shared by all three sites. The helper accumulates
the total delay and returns -ETIMEDOUT if firmware keeps returning a
busy status beyond RTAS_FADUMP_MAX_WAIT_MS (60 seconds). A pr_debug()
message is emitted on each busy iteration to aid diagnosis when the
timeout is hit.
Signed-off-by: Adriano Vero <adri.vero.dev@gmail.com>
Reviewed-by: Sourabh Jain <sourabhjain@linux.ibm.com>
---
arch/powerpc/platforms/pseries/rtas-fadump.c | 80 ++++++++++++--------
arch/powerpc/platforms/pseries/rtas-fadump.h | 6 ++
2 files changed, 53 insertions(+), 33 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/rtas-fadump.c b/arch/powerpc/platforms/pseries/rtas-fadump.c
index eceb3289383e..3bb4ac2ab6cc 100644
--- a/arch/powerpc/platforms/pseries/rtas-fadump.c
+++ b/arch/powerpc/platforms/pseries/rtas-fadump.c
@@ -179,9 +179,42 @@ static u64 rtas_fadump_get_bootmem_min(void)
return RTAS_FADUMP_MIN_BOOT_MEM;
}
+/*
+ * Helper to make an ibm,configure-kernel-dump RTAS call with a bounded
+ * busy-wait loop. Returns the RTAS return code on completion, or
+ * -ETIMEDOUT if firmware keeps returning a busy status beyond
+ * RTAS_FADUMP_MAX_WAIT_MS milliseconds.
+ */
+static int rtas_fadump_call(struct fw_dump *fadump_conf, int operation,
+ void *fdm_ptr, unsigned int fdm_size,
+ const char *op_name)
+{
+ unsigned int wait_time, total_wait = 0;
+ int rc;
+
+ do {
+ rc = rtas_call(fadump_conf->ibm_configure_kernel_dump, 3, 1,
+ NULL, operation, fdm_ptr, fdm_size);
+ wait_time = rtas_busy_delay_time(rc);
+ if (wait_time) {
+ pr_debug("Firmware busy during fadump %s, waiting %ums (total %ums)\n",
+ op_name, wait_time, total_wait);
+ if (total_wait >= RTAS_FADUMP_MAX_WAIT_MS) {
+ pr_err("Timed out waiting for firmware to complete fadump %s\n",
+ op_name);
+ return -ETIMEDOUT;
+ }
+ total_wait += wait_time;
+ mdelay(wait_time);
+ }
+ } while (wait_time);
+
+ return rc;
+}
+
static int rtas_fadump_register(struct fw_dump *fadump_conf)
{
- unsigned int wait_time, fdm_size;
+ unsigned int fdm_size;
int rc, err = -EIO;
/*
@@ -192,16 +225,10 @@ static int rtas_fadump_register(struct fw_dump *fadump_conf)
fdm_size = sizeof(struct rtas_fadump_section_header);
fdm_size += be16_to_cpu(fdm.header.dump_num_sections) * sizeof(struct rtas_fadump_section);
- /* TODO: Add upper time limit for the delay */
- do {
- rc = rtas_call(fadump_conf->ibm_configure_kernel_dump, 3, 1,
- NULL, FADUMP_REGISTER, &fdm, fdm_size);
-
- wait_time = rtas_busy_delay_time(rc);
- if (wait_time)
- mdelay(wait_time);
-
- } while (wait_time);
+ rc = rtas_fadump_call(fadump_conf, FADUMP_REGISTER, &fdm, fdm_size,
+ "register");
+ if (rc == -ETIMEDOUT)
+ return -ETIMEDOUT;
switch (rc) {
case 0:
@@ -234,19 +261,12 @@ static int rtas_fadump_register(struct fw_dump *fadump_conf)
static int rtas_fadump_unregister(struct fw_dump *fadump_conf)
{
- unsigned int wait_time;
int rc;
- /* TODO: Add upper time limit for the delay */
- do {
- rc = rtas_call(fadump_conf->ibm_configure_kernel_dump, 3, 1,
- NULL, FADUMP_UNREGISTER, &fdm,
- sizeof(struct rtas_fadump_mem_struct));
-
- wait_time = rtas_busy_delay_time(rc);
- if (wait_time)
- mdelay(wait_time);
- } while (wait_time);
+ rc = rtas_fadump_call(fadump_conf, FADUMP_UNREGISTER, &fdm,
+ sizeof(struct rtas_fadump_mem_struct), "unregister");
+ if (rc == -ETIMEDOUT)
+ return -ETIMEDOUT;
if (rc) {
pr_err("Failed to un-register - unexpected error(%d).\n", rc);
@@ -259,19 +279,13 @@ static int rtas_fadump_unregister(struct fw_dump *fadump_conf)
static int rtas_fadump_invalidate(struct fw_dump *fadump_conf)
{
- unsigned int wait_time;
int rc;
- /* TODO: Add upper time limit for the delay */
- do {
- rc = rtas_call(fadump_conf->ibm_configure_kernel_dump, 3, 1,
- NULL, FADUMP_INVALIDATE, fdm_active,
- sizeof(struct rtas_fadump_mem_struct));
-
- wait_time = rtas_busy_delay_time(rc);
- if (wait_time)
- mdelay(wait_time);
- } while (wait_time);
+ rc = rtas_fadump_call(fadump_conf, FADUMP_INVALIDATE,
+ (void *)fdm_active,
+ sizeof(struct rtas_fadump_mem_struct), "invalidate");
+ if (rc == -ETIMEDOUT)
+ return -ETIMEDOUT;
if (rc) {
pr_err("Failed to invalidate - unexpected error (%d).\n", rc);
diff --git a/arch/powerpc/platforms/pseries/rtas-fadump.h b/arch/powerpc/platforms/pseries/rtas-fadump.h
index c109abf6befd..65fdab7b5b8d 100644
--- a/arch/powerpc/platforms/pseries/rtas-fadump.h
+++ b/arch/powerpc/platforms/pseries/rtas-fadump.h
@@ -41,6 +41,12 @@
#define MAX_SECTIONS 10
#define RTAS_FADUMP_MAX_BOOT_MEM_REGS 7
+/*
+ * Maximum time to wait for firmware to respond to an
+ * ibm,configure-kernel-dump RTAS call before giving up.
+ */
+#define RTAS_FADUMP_MAX_WAIT_MS 60000U
+
/* Kernel Dump section info */
struct rtas_fadump_section {
__be32 request_flag;
--
2.54.0Hello Adriano,
On 07/05/26 03:50, Adriano Vero wrote:
> The ibm,configure-kernel-dump RTAS call sites in
> rtas_fadump_register(), rtas_fadump_unregister(), and
> rtas_fadump_invalidate() polled indefinitely while firmware returned
> a busy status. A misbehaving or hung firmware could stall these paths
> forever, blocking fadump registration at boot or preventing clean
> teardown.
>
> Introduce rtas_fadump_call(), a helper that wraps the common
> busy-wait pattern shared by all three sites. The helper accumulates
> the total delay and returns -ETIMEDOUT if firmware keeps returning a
> busy status beyond RTAS_FADUMP_MAX_WAIT_MS (60 seconds). A pr_debug()
> message is emitted on each busy iteration to aid diagnosis when the
> timeout is hit.
>
> Signed-off-by: Adriano Vero <adri.vero.dev@gmail.com>
>
> Reviewed-by: Sourabh Jain <sourabhjain@linux.ibm.com>
New line between tags is unnecessary.
Including a Changelog in subsequent versions of the same patch is
helpful for the maintainer and reviewers to understand what has changed
in this version compared to the previous version.
For example:
https://lore.kernel.org/all/20260407124349.1698552-1-sourabhjain@linux.ibm.com/
Thanks,
Sourabh Jain
> ---
> arch/powerpc/platforms/pseries/rtas-fadump.c | 80 ++++++++++++--------
> arch/powerpc/platforms/pseries/rtas-fadump.h | 6 ++
> 2 files changed, 53 insertions(+), 33 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/rtas-fadump.c b/arch/powerpc/platforms/pseries/rtas-fadump.c
> index eceb3289383e..3bb4ac2ab6cc 100644
> --- a/arch/powerpc/platforms/pseries/rtas-fadump.c
> +++ b/arch/powerpc/platforms/pseries/rtas-fadump.c
> @@ -179,9 +179,42 @@ static u64 rtas_fadump_get_bootmem_min(void)
> return RTAS_FADUMP_MIN_BOOT_MEM;
> }
>
> +/*
> + * Helper to make an ibm,configure-kernel-dump RTAS call with a bounded
> + * busy-wait loop. Returns the RTAS return code on completion, or
> + * -ETIMEDOUT if firmware keeps returning a busy status beyond
> + * RTAS_FADUMP_MAX_WAIT_MS milliseconds.
> + */
> +static int rtas_fadump_call(struct fw_dump *fadump_conf, int operation,
> + void *fdm_ptr, unsigned int fdm_size,
> + const char *op_name)
> +{
> + unsigned int wait_time, total_wait = 0;
> + int rc;
> +
> + do {
> + rc = rtas_call(fadump_conf->ibm_configure_kernel_dump, 3, 1,
> + NULL, operation, fdm_ptr, fdm_size);
> + wait_time = rtas_busy_delay_time(rc);
> + if (wait_time) {
> + pr_debug("Firmware busy during fadump %s, waiting %ums (total %ums)\n",
> + op_name, wait_time, total_wait);
> + if (total_wait >= RTAS_FADUMP_MAX_WAIT_MS) {
> + pr_err("Timed out waiting for firmware to complete fadump %s\n",
> + op_name);
> + return -ETIMEDOUT;
> + }
> + total_wait += wait_time;
> + mdelay(wait_time);
> + }
> + } while (wait_time);
> +
> + return rc;
> +}
> +
> static int rtas_fadump_register(struct fw_dump *fadump_conf)
> {
> - unsigned int wait_time, fdm_size;
> + unsigned int fdm_size;
> int rc, err = -EIO;
>
> /*
> @@ -192,16 +225,10 @@ static int rtas_fadump_register(struct fw_dump *fadump_conf)
> fdm_size = sizeof(struct rtas_fadump_section_header);
> fdm_size += be16_to_cpu(fdm.header.dump_num_sections) * sizeof(struct rtas_fadump_section);
>
> - /* TODO: Add upper time limit for the delay */
> - do {
> - rc = rtas_call(fadump_conf->ibm_configure_kernel_dump, 3, 1,
> - NULL, FADUMP_REGISTER, &fdm, fdm_size);
> -
> - wait_time = rtas_busy_delay_time(rc);
> - if (wait_time)
> - mdelay(wait_time);
> -
> - } while (wait_time);
> + rc = rtas_fadump_call(fadump_conf, FADUMP_REGISTER, &fdm, fdm_size,
> + "register");
> + if (rc == -ETIMEDOUT)
> + return -ETIMEDOUT;
>
> switch (rc) {
> case 0:
> @@ -234,19 +261,12 @@ static int rtas_fadump_register(struct fw_dump *fadump_conf)
>
> static int rtas_fadump_unregister(struct fw_dump *fadump_conf)
> {
> - unsigned int wait_time;
> int rc;
>
> - /* TODO: Add upper time limit for the delay */
> - do {
> - rc = rtas_call(fadump_conf->ibm_configure_kernel_dump, 3, 1,
> - NULL, FADUMP_UNREGISTER, &fdm,
> - sizeof(struct rtas_fadump_mem_struct));
> -
> - wait_time = rtas_busy_delay_time(rc);
> - if (wait_time)
> - mdelay(wait_time);
> - } while (wait_time);
> + rc = rtas_fadump_call(fadump_conf, FADUMP_UNREGISTER, &fdm,
> + sizeof(struct rtas_fadump_mem_struct), "unregister");
> + if (rc == -ETIMEDOUT)
> + return -ETIMEDOUT;
>
> if (rc) {
> pr_err("Failed to un-register - unexpected error(%d).\n", rc);
> @@ -259,19 +279,13 @@ static int rtas_fadump_unregister(struct fw_dump *fadump_conf)
>
> static int rtas_fadump_invalidate(struct fw_dump *fadump_conf)
> {
> - unsigned int wait_time;
> int rc;
>
> - /* TODO: Add upper time limit for the delay */
> - do {
> - rc = rtas_call(fadump_conf->ibm_configure_kernel_dump, 3, 1,
> - NULL, FADUMP_INVALIDATE, fdm_active,
> - sizeof(struct rtas_fadump_mem_struct));
> -
> - wait_time = rtas_busy_delay_time(rc);
> - if (wait_time)
> - mdelay(wait_time);
> - } while (wait_time);
> + rc = rtas_fadump_call(fadump_conf, FADUMP_INVALIDATE,
> + (void *)fdm_active,
> + sizeof(struct rtas_fadump_mem_struct), "invalidate");
> + if (rc == -ETIMEDOUT)
> + return -ETIMEDOUT;
>
> if (rc) {
> pr_err("Failed to invalidate - unexpected error (%d).\n", rc);
> diff --git a/arch/powerpc/platforms/pseries/rtas-fadump.h b/arch/powerpc/platforms/pseries/rtas-fadump.h
> index c109abf6befd..65fdab7b5b8d 100644
> --- a/arch/powerpc/platforms/pseries/rtas-fadump.h
> +++ b/arch/powerpc/platforms/pseries/rtas-fadump.h
> @@ -41,6 +41,12 @@
> #define MAX_SECTIONS 10
> #define RTAS_FADUMP_MAX_BOOT_MEM_REGS 7
>
> +/*
> + * Maximum time to wait for firmware to respond to an
> + * ibm,configure-kernel-dump RTAS call before giving up.
> + */
> +#define RTAS_FADUMP_MAX_WAIT_MS 60000U
> +
> /* Kernel Dump section info */
> struct rtas_fadump_section {
> __be32 request_flag;
Hi Sourabh,
Understood, I'll keep that in mind for future patches. Thanks for
the guidance.
Adriano
On Thu, May 7, 2026 at 6:16 AM Sourabh Jain <sourabhjain@linux.ibm.com> wrote:
>
> Hello Adriano,
>
> On 07/05/26 03:50, Adriano Vero wrote:
> > The ibm,configure-kernel-dump RTAS call sites in
> > rtas_fadump_register(), rtas_fadump_unregister(), and
> > rtas_fadump_invalidate() polled indefinitely while firmware returned
> > a busy status. A misbehaving or hung firmware could stall these paths
> > forever, blocking fadump registration at boot or preventing clean
> > teardown.
> >
> > Introduce rtas_fadump_call(), a helper that wraps the common
> > busy-wait pattern shared by all three sites. The helper accumulates
> > the total delay and returns -ETIMEDOUT if firmware keeps returning a
> > busy status beyond RTAS_FADUMP_MAX_WAIT_MS (60 seconds). A pr_debug()
> > message is emitted on each busy iteration to aid diagnosis when the
> > timeout is hit.
> >
> > Signed-off-by: Adriano Vero <adri.vero.dev@gmail.com>
> >
> > Reviewed-by: Sourabh Jain <sourabhjain@linux.ibm.com>
>
> New line between tags is unnecessary.
>
> Including a Changelog in subsequent versions of the same patch is
> helpful for the maintainer and reviewers to understand what has changed
> in this version compared to the previous version.
>
> For example:
> https://lore.kernel.org/all/20260407124349.1698552-1-sourabhjain@linux.ibm.com/
>
> Thanks,
> Sourabh Jain
>
> > ---
> > arch/powerpc/platforms/pseries/rtas-fadump.c | 80 ++++++++++++--------
> > arch/powerpc/platforms/pseries/rtas-fadump.h | 6 ++
> > 2 files changed, 53 insertions(+), 33 deletions(-)
> >
> > diff --git a/arch/powerpc/platforms/pseries/rtas-fadump.c b/arch/powerpc/platforms/pseries/rtas-fadump.c
> > index eceb3289383e..3bb4ac2ab6cc 100644
> > --- a/arch/powerpc/platforms/pseries/rtas-fadump.c
> > +++ b/arch/powerpc/platforms/pseries/rtas-fadump.c
> > @@ -179,9 +179,42 @@ static u64 rtas_fadump_get_bootmem_min(void)
> > return RTAS_FADUMP_MIN_BOOT_MEM;
> > }
> >
> > +/*
> > + * Helper to make an ibm,configure-kernel-dump RTAS call with a bounded
> > + * busy-wait loop. Returns the RTAS return code on completion, or
> > + * -ETIMEDOUT if firmware keeps returning a busy status beyond
> > + * RTAS_FADUMP_MAX_WAIT_MS milliseconds.
> > + */
> > +static int rtas_fadump_call(struct fw_dump *fadump_conf, int operation,
> > + void *fdm_ptr, unsigned int fdm_size,
> > + const char *op_name)
> > +{
> > + unsigned int wait_time, total_wait = 0;
> > + int rc;
> > +
> > + do {
> > + rc = rtas_call(fadump_conf->ibm_configure_kernel_dump, 3, 1,
> > + NULL, operation, fdm_ptr, fdm_size);
> > + wait_time = rtas_busy_delay_time(rc);
> > + if (wait_time) {
> > + pr_debug("Firmware busy during fadump %s, waiting %ums (total %ums)\n",
> > + op_name, wait_time, total_wait);
> > + if (total_wait >= RTAS_FADUMP_MAX_WAIT_MS) {
> > + pr_err("Timed out waiting for firmware to complete fadump %s\n",
> > + op_name);
> > + return -ETIMEDOUT;
> > + }
> > + total_wait += wait_time;
> > + mdelay(wait_time);
> > + }
> > + } while (wait_time);
> > +
> > + return rc;
> > +}
> > +
> > static int rtas_fadump_register(struct fw_dump *fadump_conf)
> > {
> > - unsigned int wait_time, fdm_size;
> > + unsigned int fdm_size;
> > int rc, err = -EIO;
> >
> > /*
> > @@ -192,16 +225,10 @@ static int rtas_fadump_register(struct fw_dump *fadump_conf)
> > fdm_size = sizeof(struct rtas_fadump_section_header);
> > fdm_size += be16_to_cpu(fdm.header.dump_num_sections) * sizeof(struct rtas_fadump_section);
> >
> > - /* TODO: Add upper time limit for the delay */
> > - do {
> > - rc = rtas_call(fadump_conf->ibm_configure_kernel_dump, 3, 1,
> > - NULL, FADUMP_REGISTER, &fdm, fdm_size);
> > -
> > - wait_time = rtas_busy_delay_time(rc);
> > - if (wait_time)
> > - mdelay(wait_time);
> > -
> > - } while (wait_time);
> > + rc = rtas_fadump_call(fadump_conf, FADUMP_REGISTER, &fdm, fdm_size,
> > + "register");
> > + if (rc == -ETIMEDOUT)
> > + return -ETIMEDOUT;
> >
> > switch (rc) {
> > case 0:
> > @@ -234,19 +261,12 @@ static int rtas_fadump_register(struct fw_dump *fadump_conf)
> >
> > static int rtas_fadump_unregister(struct fw_dump *fadump_conf)
> > {
> > - unsigned int wait_time;
> > int rc;
> >
> > - /* TODO: Add upper time limit for the delay */
> > - do {
> > - rc = rtas_call(fadump_conf->ibm_configure_kernel_dump, 3, 1,
> > - NULL, FADUMP_UNREGISTER, &fdm,
> > - sizeof(struct rtas_fadump_mem_struct));
> > -
> > - wait_time = rtas_busy_delay_time(rc);
> > - if (wait_time)
> > - mdelay(wait_time);
> > - } while (wait_time);
> > + rc = rtas_fadump_call(fadump_conf, FADUMP_UNREGISTER, &fdm,
> > + sizeof(struct rtas_fadump_mem_struct), "unregister");
> > + if (rc == -ETIMEDOUT)
> > + return -ETIMEDOUT;
> >
> > if (rc) {
> > pr_err("Failed to un-register - unexpected error(%d).\n", rc);
> > @@ -259,19 +279,13 @@ static int rtas_fadump_unregister(struct fw_dump *fadump_conf)
> >
> > static int rtas_fadump_invalidate(struct fw_dump *fadump_conf)
> > {
> > - unsigned int wait_time;
> > int rc;
> >
> > - /* TODO: Add upper time limit for the delay */
> > - do {
> > - rc = rtas_call(fadump_conf->ibm_configure_kernel_dump, 3, 1,
> > - NULL, FADUMP_INVALIDATE, fdm_active,
> > - sizeof(struct rtas_fadump_mem_struct));
> > -
> > - wait_time = rtas_busy_delay_time(rc);
> > - if (wait_time)
> > - mdelay(wait_time);
> > - } while (wait_time);
> > + rc = rtas_fadump_call(fadump_conf, FADUMP_INVALIDATE,
> > + (void *)fdm_active,
> > + sizeof(struct rtas_fadump_mem_struct), "invalidate");
> > + if (rc == -ETIMEDOUT)
> > + return -ETIMEDOUT;
> >
> > if (rc) {
> > pr_err("Failed to invalidate - unexpected error (%d).\n", rc);
> > diff --git a/arch/powerpc/platforms/pseries/rtas-fadump.h b/arch/powerpc/platforms/pseries/rtas-fadump.h
> > index c109abf6befd..65fdab7b5b8d 100644
> > --- a/arch/powerpc/platforms/pseries/rtas-fadump.h
> > +++ b/arch/powerpc/platforms/pseries/rtas-fadump.h
> > @@ -41,6 +41,12 @@
> > #define MAX_SECTIONS 10
> > #define RTAS_FADUMP_MAX_BOOT_MEM_REGS 7
> >
> > +/*
> > + * Maximum time to wait for firmware to respond to an
> > + * ibm,configure-kernel-dump RTAS call before giving up.
> > + */
> > +#define RTAS_FADUMP_MAX_WAIT_MS 60000U
> > +
> > /* Kernel Dump section info */
> > struct rtas_fadump_section {
> > __be32 request_flag;
>
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