[S390] kprobes: Fix the return address of multiple kretprobes

Analog to git commit 737480a0d525dae13306296da08029dff545bc72
fix the return address of subsequent kretprobes when multiple
kretprobes are set on the same function.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index 70cf73bdba25b0871aec47ff6ca4f835f5e6d7b3..2564793ec2b6fd0dede210f10694615606239511 100644 (file)
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -349,6 +349,7 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p,
        struct hlist_node *node, *tmp;
        unsigned long flags, orig_ret_address = 0;
        unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline;
+       kprobe_opcode_t *correct_ret_addr = NULL;
 
        INIT_HLIST_HEAD(&empty_rp);
        kretprobe_hash_lock(current, &head, &flags);
@@ -371,10 +372,32 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p,
                        /* another task is sharing our hash bucket */
                        continue;
 
-               if (ri->rp && ri->rp->handler)
-                       ri->rp->handler(ri, regs);
+               orig_ret_address = (unsigned long)ri->ret_addr;
+
+               if (orig_ret_address != trampoline_address)
+                       /*
+                        * This is the real return address. Any other
+                        * instances associated with this task are for
+                        * other calls deeper on the call stack
+                        */
+                       break;
+       }
+
+       kretprobe_assert(ri, orig_ret_address, trampoline_address);
+
+       correct_ret_addr = ri->ret_addr;
+       hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
+               if (ri->task != current)
+                       /* another task is sharing our hash bucket */
+                       continue;
 
                orig_ret_address = (unsigned long)ri->ret_addr;
+
+               if (ri->rp && ri->rp->handler) {
+                       ri->ret_addr = correct_ret_addr;
+                       ri->rp->handler(ri, regs);
+               }
+
                recycle_rp_inst(ri, &empty_rp);
 
                if (orig_ret_address != trampoline_address) {
@@ -386,7 +409,7 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p,
                        break;
                }
        }
-       kretprobe_assert(ri, orig_ret_address, trampoline_address);
+
        regs->psw.addr = orig_ret_address | PSW_ADDR_AMODE;
 
        reset_current_kprobe();