[PATCH v3 powerpc] perf/hv-24x7 fail 24x7 initcall if create_events_from_catalog() fails

[Li Zhong]

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 <zh...@linux.vnet.ibm.com>
---
 arch/powerpc/perf/hv-24x7.c | 37 +++++++++++++++++++++++++++++--------
 1 file changed, 29 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c
index 9445a82..ead1420 100644
--- a/arch/powerpc/perf/hv-24x7.c
+++ b/arch/powerpc/perf/hv-24x7.c
@@ -637,7 +637,7 @@ 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_)
 {
@@ -655,19 +655,25 @@ 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;
        }
 
@@ -686,6 +692,7 @@ 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;
        }
 
@@ -694,12 +701,14 @@ 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;
        }
 
@@ -712,6 +721,7 @@ 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;
        }
 
@@ -731,6 +741,7 @@ 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;
                }
        }
@@ -778,18 +789,24 @@ 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,
@@ -843,7 +860,7 @@ 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);
@@ -857,6 +874,7 @@ e_out:
        *events_ = NULL;
        *event_descs_ = NULL;
        *event_long_descs_ = NULL;
+       return ret;
 }
 
 static ssize_t catalog_read(struct file *filp, struct kobject *kobj,
@@ -1219,10 +1237,13 @@ 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;



_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev