powerpc/perf/hv-24x7: Fail 24x7 initcall if create_events_from_catalog() fails

As Michael pointed out, create_events_from_catalog() fails when we
either have:
 - a kernel bug
 - some sort of hypervisor misconfiguration
 - ENOMEM

In all the above cases, we can also fail 24x7 initcall.

For hypervisor errors, EIO is used so there is something reported
in dmesg.

Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 29 insertions, 8 deletions

diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c
index ead8878ca62b..ff413615a87c 100644
--- a/arch/powerpc/perf/hv-24x7.c
+++ b/arch/powerpc/perf/hv-24x7.c
@@ -647,7 +647,7 @@ static ssize_t catalog_event_len_validate(struct hv_24x7_event_data *event,
 
 #define MAX_4K (SIZE_MAX / 4096)
 
-static void create_events_from_catalog(struct attribute ***events_,
+static int create_events_from_catalog(struct attribute ***events_,
                 struct attribute ***event_descs_,
                 struct attribute ***event_long_descs_)
 {
@@ -665,19 +665,25 @@ static void create_events_from_catalog(struct attribute ***events_,
         void *event_data, *end;
         struct hv_24x7_event_data *event;
         struct rb_root ev_uniq = RB_ROOT;
+        int ret = 0;
 
-        if (!page)
+        if (!page) {
+                ret = -ENOMEM;
                 goto e_out;
+        }
 
         hret = h_get_24x7_catalog_page(page, 0, 0);
-        if (hret)
+        if (hret) {
+                ret = -EIO;
                 goto e_free;
+        }
 
         catalog_version_num = be64_to_cpu(page_0->version);
         catalog_page_len = be32_to_cpu(page_0->length);
 
         if (MAX_4K < catalog_page_len) {
                 pr_err("invalid page count: %zu\n", catalog_page_len);
+                ret = -EIO;
                 goto e_free;
         }
 
@@ -696,6 +702,7 @@ static void create_events_from_catalog(struct attribute ***events_,
                         || (MAX_4K - event_data_offs < event_data_len)) {
                 pr_err("invalid event data offs %zu and/or len %zu\n",
                                 event_data_offs, event_data_len);
+                ret = -EIO;
                 goto e_free;
         }
 
@@ -704,12 +711,14 @@ static void create_events_from_catalog(struct attribute ***events_,
                                 event_data_offs,
                                 event_data_offs + event_data_len,
                                 catalog_page_len);
+                ret = -EIO;
                 goto e_free;
         }
 
         if (SIZE_MAX / MAX_EVENTS_PER_EVENT_DATA - 1 < event_entry_count) {
                 pr_err("event_entry_count %zu is invalid\n",
                                 event_entry_count);
+                ret = -EIO;
                 goto e_free;
         }
 
@@ -722,6 +731,7 @@ static void create_events_from_catalog(struct attribute ***events_,
         event_data = vmalloc(event_data_bytes);
         if (!event_data) {
                 pr_err("could not allocate event data\n");
+                ret = -ENOMEM;
                 goto e_free;
         }
 
@@ -741,6 +751,7 @@ static void create_events_from_catalog(struct attribute ***events_,
                 if (hret) {
                         pr_err("failed to get event data in page %zu\n",
                                         i + event_data_offs);
+                        ret = -EIO;
                         goto e_event_data;
                 }
         }
@@ -788,18 +799,24 @@ static void create_events_from_catalog(struct attribute ***events_,
                                 event_idx_last, event_entry_count, junk_events);
 
         events = kmalloc_array(attr_max + 1, sizeof(*events), GFP_KERNEL);
-        if (!events)
+        if (!events) {
+                ret = -ENOMEM;
                 goto e_event_data;
+        }
 
         event_descs = kmalloc_array(event_idx + 1, sizeof(*event_descs),
                                 GFP_KERNEL);
-        if (!event_descs)
+        if (!event_descs) {
+                ret = -ENOMEM;
                 goto e_event_attrs;
+        }
 
         event_long_descs = kmalloc_array(event_idx + 1,
                         sizeof(*event_long_descs), GFP_KERNEL);
-        if (!event_long_descs)
+        if (!event_long_descs) {
+                ret = -ENOMEM;
                 goto e_event_descs;
+        }
 
         /* Iterate over the catalog filling in the attribute vector */
         for (junk_events = 0, event_attr_ct = 0, desc_ct = 0, long_desc_ct = 0,
@@ -853,7 +870,7 @@ static void create_events_from_catalog(struct attribute ***events_,
         *events_ = events;
         *event_descs_ = event_descs;
         *event_long_descs_ = event_long_descs;
-        return;
+        return 0;
 
 e_event_descs:
         kfree(event_descs);
@@ -867,6 +884,7 @@ e_out:
         *events_ = NULL;
         *event_descs_ = NULL;
         *event_long_descs_ = NULL;
+        return ret;
 }
 
 static ssize_t catalog_read(struct file *filp, struct kobject *kobj,
@@ -1275,10 +1293,13 @@ static int hv_24x7_init(void)
         /* sampling not supported */
         h_24x7_pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
 
-        create_events_from_catalog(&event_group.attrs,
+        r = create_events_from_catalog(&event_group.attrs,
                                    &event_desc_group.attrs,
                                    &event_long_desc_group.attrs);
 
+        if (r)
+                return r;
+
         r = perf_pmu_register(&h_24x7_pmu, h_24x7_pmu.name, -1);
         if (r)
                 return r;