dtrace: increase instruction limit for FBT entry probe detection

The logic used to detect whether we can place a FBT entry probe on
a function has a limit on how many instructions should be looked
at.  With the occurrence of longer function prologues, that limit
must be increased.  This commit changes it from 2 to 10.

Orabug: 27410742
Signed-off-by: Kris Van Hees <kris.van.hees@oracle.com>
Reviewed-by: Tomas Jedlicka <tomas.jedlicka@oracle.com>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>

diff --git a/arch/x86/kernel/dtrace_fbt.c b/arch/x86/kernel/dtrace_fbt.c
index 549af864ec25dd333bb5ccc7cb607c29b025af99..2d7ed6efb4a8d4d72a2107cf157c67f9a4aff7b0 100644 (file)
--- a/arch/x86/kernel/dtrace_fbt.c
+++ b/arch/x86/kernel/dtrace_fbt.c
@@ -146,7 +146,7 @@ void dtrace_fbt_init(fbt_add_probe_fn fbt_add_probe, struct module *mp,
                                                FBT_ENTRY, *addr, addr, 0,
                                                NULL, arg);
                                        state = 1;
-                               } else if (insc > 2)
+                               } else if (insc > 10)
                                        state = 2;
                                break;
                        case 1: /* look for ret */