@@ -3334,7 +3334,7 @@ static void acpi_nfit_init_ars(struct acpi_nfit_desc *acpi_desc,
static int acpi_nfit_register_regions(struct acpi_nfit_desc *acpi_desc)
{
struct nfit_spa *nfit_spa;
- int rc;
+ int rc, do_sched_ars = 0;
set_bit(ARS_VALID, &acpi_desc->scrub_flags);
list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
@@ -3346,7 +3346,7 @@ static int acpi_nfit_register_regions(struct acpi_nfit_desc *acpi_desc)
}
}
- list_for_each_entry(nfit_spa, &acpi_desc->spas, list)
+ list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
switch (nfit_spa_type(nfit_spa->spa)) {
case NFIT_SPA_VOLATILE:
case NFIT_SPA_PM:
@@ -3354,6 +3354,13 @@ static int acpi_nfit_register_regions(struct acpi_nfit_desc *acpi_desc)
rc = ars_register(acpi_desc, nfit_spa);
if (rc)
return rc;
+
+ /*
+ * Kick off background ARS if at least one
+ * region successfully registered ARS
+ */
+ if (!test_bit(ARS_FAILED, &nfit_spa->ars_state))
+ do_sched_ars++;
break;
case NFIT_SPA_BDW:
/* nothing to register */
@@ -3372,8 +3379,10 @@ static int acpi_nfit_register_regions(struct acpi_nfit_desc *acpi_desc)
/* don't register unknown regions */
break;
}
+ }
- sched_ars(acpi_desc);
+ if (do_sched_ars)
+ sched_ars(acpi_desc);
return 0;
}
Pending commit in -next "devres: handle zero size in devm_kmalloc()" triggers a boot regression due to the ARS implementation expecting NULL from a zero-sized allocation. Avoid the zero-sized allocation by skipping ARS, otherwise crashes with the following signature when de-referencing ZERO_SIZE_PTR. BUG: kernel NULL pointer dereference, address: 0000000000000018 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page RIP: 0010:__acpi_nfit_scrub+0x28a/0x350 [nfit] [..] Call Trace: ? acpi_nfit_query_poison+0x6a/0x180 [nfit] acpi_nfit_scrub+0x36/0xb0 [nfit] process_one_work+0x23c/0x580 worker_thread+0x50/0x3b0 Otherwise the implementation correctly aborts when NULL is returned from devm_kzalloc() in ars_status_alloc(). Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> --- drivers/acpi/nfit/core.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)