data_breakpoint.ko can insert successful but cannot catch any change of
the data in my part because kallsyms_lookup_name rerurn 0 each time.
So add code to check the return value of kallsyms_lookup_name.
Signed-off-by: Hui Zhu <zhu...@xiaomi.com>
---
samples/hw_breakpoint/data_breakpoint.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
diff --git a/samples/hw_breakpoint/data_breakpoint.c
b/samples/hw_breakpoint/data_breakpoint.c
index ef7f322..4fbf93b 100644
--- a/samples/hw_breakpoint/data_breakpoint.c
+++ b/samples/hw_breakpoint/data_breakpoint.c
@@ -52,27 +52,30 @@ static void sample_hbp_handler(struct perf_event *bp,
static int __init hw_break_module_init(void)
{
- int ret;
+ int ret = 0;
struct perf_event_attr attr;
hw_breakpoint_init(&attr);
attr.bp_addr = kallsyms_lookup_name(ksym_name);
+ if (!attr.bp_addr) {
+ ret = -ENXIO;
+ printk(KERN_INFO "Get address for %s failed\n", ksym_name);
+ goto out;
+ }
+
attr.bp_len = HW_BREAKPOINT_LEN_4;
attr.bp_type = HW_BREAKPOINT_W | HW_BREAKPOINT_R;
sample_hbp = register_wide_hw_breakpoint(&attr, sample_hbp_handler,
NULL);
if (IS_ERR((void __force *)sample_hbp)) {
ret = PTR_ERR((void __force *)sample_hbp);
- goto fail;
+ printk(KERN_INFO "Breakpoint registration failed\n");
+ goto out;
}
printk(KERN_INFO "HW Breakpoint for %s write installed\n", ksym_name);
- return 0;
-
-fail:
- printk(KERN_INFO "Breakpoint registration failed\n");
-
+out:
return ret;
}
--
1.9.1
--
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