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kpatch module integration test
This tests several things related to the patching of modules:
- 'kpatch_string' tests the referencing of a symbol which is outside the
.o, but inside the patch module.
- alternatives patching (.altinstructions)
- paravirt patching (.parainstructions)
- jump labels (5.8+ kernels only) -- including dynamic printk
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
diff --git a/fs/xfs/xfs_stats.c b/fs/xfs/xfs_stats.c
index 90a77cd3ebad..f65df90ae8e1 100644
--- a/fs/xfs/xfs_stats.c
+++ b/fs/xfs/xfs_stats.c
@@ -16,6 +16,8 @@ static int counter_val(struct xfsstats __percpu *stats, int idx)
return val;
}
+extern char *kpatch_string(void);
+
int xfs_stats_format(struct xfsstats __percpu *stats, char *buf)
{
int i, j;
@@ -85,6 +87,34 @@ int xfs_stats_format(struct xfsstats __percpu *stats, char *buf)
0);
#endif
+ /* Reference a symbol outside the .o yet inside the patch module: */
+ len += scnprintf(buf + len, PATH_MAX-len, "%s\n", kpatch_string());
+
+#ifdef CONFIG_X86_64
+ /* Test alternatives patching: */
+ alternative("ud2", "nop", X86_FEATURE_ALWAYS);
+ alternative("nop", "ud2", X86_FEATURE_IA64);
+
+ /* Test paravirt patching: */
+ slow_down_io(); /* paravirt call */
+#endif
+
+ /* Test pr_debug: */
+ pr_debug("kpatch: pr_debug() test\n");
+
+{
+ /* Test static branches: */
+ static DEFINE_STATIC_KEY_TRUE(kpatch_key);
+
+ if (static_branch_unlikely(&memcg_kmem_enabled_key))
+ printk("kpatch: memcg_kmem_enabled_key\n");
+
+ BUG_ON(!static_branch_likely(&kpatch_key));
+ static_branch_disable(&kpatch_key);
+ BUG_ON(static_branch_likely(&kpatch_key));
+ static_branch_enable(&kpatch_key);
+}
+
return len;
}
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index c64277659753..05b753c2ec84 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2980,4 +2980,9 @@ static int __init netlink_proto_init(void)
panic("netlink_init: Cannot allocate nl_table\n");
}
+char *kpatch_string(void)
+{
+ return "kpatch";
+}
+
core_initcall(netlink_proto_init);
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