[FIX] ARM: add mandatory lr check on uretprobes disarming

Change-Id: I82cc9b63b6a338760dc332333e9b8659af878b71
Signed-off-by: Vasiliy Ulyanov <v.ulyanov@samsung.com>

diff --git a/uprobe/arch/asm-arm/swap_uprobes.c b/uprobe/arch/asm-arm/swap_uprobes.c
index 7951863..728409f 100644 (file)
--- a/uprobe/arch/asm-arm/swap_uprobes.c
+++ b/uprobe/arch/asm-arm/swap_uprobes.c
@@ -599,6 +599,8 @@ void arch_prepare_uretprobe(struct uretprobe_instance *ri,
 int arch_disarm_urp_inst(struct uretprobe_instance *ri,
                         struct task_struct *task)
 {
+       struct pt_regs *uregs = task_pt_regs(ri->task);
+       unsigned long ra = dbi_get_ret_addr(uregs);
        unsigned long *tramp;
        unsigned long *sp = (unsigned long *)((long)ri->sp & ~1);
        unsigned long *stack = sp - RETPROBE_STACK_DEPTH + 1;
@@ -615,6 +617,7 @@ int arch_disarm_urp_inst(struct uretprobe_instance *ri,
                                          UPROBES_TRAMP_RET_BREAK_IDX);
        }
 
+       /* check stack */
        retval = read_proc_vm_atomic(task, (unsigned long)stack,
                                     buf, sizeof(buf));
        if (retval != sizeof(buf)) {
@@ -622,7 +625,7 @@ int arch_disarm_urp_inst(struct uretprobe_instance *ri,
                       task->comm, task->tgid, task->pid,
                       (unsigned long)stack);
                retval = -EFAULT;
-               goto out;
+               goto check_lr;
        }
 
        /* search the stack from the bottom */
@@ -633,43 +636,42 @@ int arch_disarm_urp_inst(struct uretprobe_instance *ri,
                }
        }
 
-       if (found) {
+       if (!found) {
+               retval = -ESRCH;
+               goto check_lr;
+       }
+
+       printk("---> %s (%d/%d): trampoline found at "
+              "%08lx (%08lx /%+d) - %p\n",
+              task->comm, task->tgid, task->pid,
+              (unsigned long)found, (unsigned long)sp,
+              found - sp, ri->rp->up.kp.addr);
+       retval = write_proc_vm_atomic(task, (unsigned long)found,
+                                     &ri->ret_addr,
+                                     sizeof(ri->ret_addr));
+       if (retval != sizeof(ri->ret_addr)) {
+               printk("---> %s (%d/%d): failed to write value to %08lx",
+                      task->comm, task->tgid, task->pid, (unsigned long)found);
+               retval = -EFAULT;
+       } else {
+               retval = 0;
+       }
+
+check_lr: /* check lr anyway */
+       if (ra == (unsigned long)tramp) {
                printk("---> %s (%d/%d): trampoline found at "
-                      "%08lx (%08lx /%+d) - %p\n",
+                      "lr = %08lx - %p\n",
                       task->comm, task->tgid, task->pid,
-                      (unsigned long)found, (unsigned long)sp,
-                      found - sp, ri->rp->up.kp.addr);
-               retval = write_proc_vm_atomic(task, (unsigned long)found,
-                                             &ri->ret_addr,
-                                             sizeof(ri->ret_addr));
-               if (retval != sizeof(ri->ret_addr)) {
-                       printk("---> %s (%d/%d): failed to write value "
-                              "to %08lx",
-                              task->comm, task->tgid, task->pid, (unsigned long)found);
-                       retval = -EFAULT;
-               } else {
-                       retval = 0;
-               }
-       } else {
-               struct pt_regs *uregs = task_pt_regs(ri->task);
-               unsigned long ra = dbi_get_ret_addr(uregs);
-               if (ra == (unsigned long)tramp) {
-                       printk("---> %s (%d/%d): trampoline found at "
-                              "lr = %08lx - %p\n",
-                              task->comm, task->tgid, task->pid,
-                              ra, ri->rp->up.kp.addr);
-                       dbi_set_ret_addr(uregs, (unsigned long)ri->ret_addr);
-                       retval = 0;
-               } else {
-                       printk("---> %s (%d/%d): trampoline NOT found at "
-                              "sp = %08lx, lr = %08lx - %p\n",
-                              task->comm, task->tgid, task->pid,
-                              (unsigned long)sp, ra, ri->rp->up.kp.addr);
-                       retval = -ENOENT;
-               }
+                      ra, ri->rp->up.kp.addr);
+               dbi_set_ret_addr(uregs, (unsigned long)ri->ret_addr);
+               retval = 0;
+       } else if (retval) {
+               printk("---> %s (%d/%d): trampoline NOT found at "
+                      "sp = %08lx, lr = %08lx - %p\n",
+                      task->comm, task->tgid, task->pid,
+                      (unsigned long)sp, ra, ri->rp->up.kp.addr);
        }
 
-out:
        return retval;
 }