7 files changed, 42 insertions, 30 deletions

diff --git a/arch/um/os-Linux/aio.c b/arch/um/os-Linux/aio.c
index 4158118c4a56..93dc0c80ebaf 100644
--- a/arch/um/os-Linux/aio.c
+++ b/arch/um/os-Linux/aio.c
@@ -218,7 +218,7 @@ static int init_aio_24(void)
                 goto out_close_pipe;
 
         err = run_helper_thread(not_aio_thread, NULL,
-                                CLONE_FILES | CLONE_VM | SIGCHLD, &aio_stack);
+                                CLONE_FILES | CLONE_VM, &aio_stack);
         if (err < 0)
                 goto out_close_pipe;
 
@@ -254,7 +254,7 @@ static int init_aio_26(void)
         }
 
         err = run_helper_thread(aio_thread, NULL,
-                                CLONE_FILES | CLONE_VM | SIGCHLD, &aio_stack);
+                                CLONE_FILES | CLONE_VM, &aio_stack);
         if (err < 0)
                 return err;
 
diff --git a/arch/um/os-Linux/drivers/ethertap_user.c b/arch/um/os-Linux/drivers/ethertap_user.c
index 4ff553603449..07ca0cb472ac 100644
--- a/arch/um/os-Linux/drivers/ethertap_user.c
+++ b/arch/um/os-Linux/drivers/ethertap_user.c
@@ -94,7 +94,7 @@ static int etap_tramp(char *dev, char *gate, int control_me,
                       int control_remote, int data_me, int data_remote)
 {
         struct etap_pre_exec_data pe_data;
-        int pid, status, err, n;
+        int pid, err, n;
         char version_buf[sizeof("nnnnn\0")];
         char data_fd_buf[sizeof("nnnnnn\0")];
         char gate_buf[sizeof("nnn.nnn.nnn.nnn\0")];
@@ -131,13 +131,7 @@ static int etap_tramp(char *dev, char *gate, int control_me,
         }
         if (c != 1) {
                 printk(UM_KERN_ERR "etap_tramp : uml_net failed\n");
-                err = -EINVAL;
-                CATCH_EINTR(n = waitpid(pid, &status, 0));
-                if (n < 0)
-                        err = -errno;
-                else if (!WIFEXITED(status) || (WEXITSTATUS(status) != 1))
-                        printk(UM_KERN_ERR "uml_net didn't exit with "
-                               "status 1\n");
+                err = helper_wait(pid, 0, "uml_net");
         }
         return err;
 }
diff --git a/arch/um/os-Linux/drivers/tuntap_user.c b/arch/um/os-Linux/drivers/tuntap_user.c
index 6c55d3c8ead8..1037a3b6386e 100644
--- a/arch/um/os-Linux/drivers/tuntap_user.c
+++ b/arch/um/os-Linux/drivers/tuntap_user.c
@@ -107,7 +107,7 @@ static int tuntap_open_tramp(char *gate, int *fd_out, int me, int remote,
                        "errno = %d\n", errno);
                 return err;
         }
-        CATCH_EINTR(waitpid(pid, NULL, 0));
+        helper_wait(pid, 0, "tuntap_open_tramp");
 
         cmsg = CMSG_FIRSTHDR(&msg);
         if (cmsg == NULL) {
diff --git a/arch/um/os-Linux/helper.c b/arch/um/os-Linux/helper.c
index 7a72dbb61b0d..fba3f0fefeef 100644
--- a/arch/um/os-Linux/helper.c
+++ b/arch/um/os-Linux/helper.c
@@ -76,7 +76,7 @@ int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv)
         data.fd = fds[1];
         data.buf = __cant_sleep() ? kmalloc(PATH_MAX, UM_GFP_ATOMIC) :
                                         kmalloc(PATH_MAX, UM_GFP_KERNEL);
-        pid = clone(helper_child, (void *) sp, CLONE_VM | SIGCHLD, &data);
+        pid = clone(helper_child, (void *) sp, CLONE_VM, &data);
         if (pid < 0) {
                 ret = -errno;
                 printk("run_helper : clone failed, errno = %d\n", errno);
@@ -101,7 +101,7 @@ int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv)
                         ret = n;
                         kill(pid, SIGKILL);
                 }
-                CATCH_EINTR(waitpid(pid, NULL, 0));
+                CATCH_EINTR(waitpid(pid, NULL, __WCLONE));
         }
 
 out_free2:
@@ -126,7 +126,7 @@ int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags,
                 return -ENOMEM;
 
         sp = stack + UM_KERN_PAGE_SIZE - sizeof(void *);
-        pid = clone(proc, (void *) sp, flags | SIGCHLD, arg);
+        pid = clone(proc, (void *) sp, flags, arg);
         if (pid < 0) {
                 err = -errno;
                 printk("run_helper_thread : clone failed, errno = %d\n",
@@ -134,7 +134,7 @@ int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags,
                 return err;
         }
         if (stack_out == NULL) {
-                CATCH_EINTR(pid = waitpid(pid, &status, 0));
+                CATCH_EINTR(pid = waitpid(pid, &status, __WCLONE));
                 if (pid < 0) {
                         err = -errno;
                         printk("run_helper_thread - wait failed, errno = %d\n",
@@ -150,14 +150,30 @@ int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags,
         return pid;
 }
 
-int helper_wait(int pid)
+int helper_wait(int pid, int nohang, char *pname)
 {
-        int ret;
+        int ret, status;
+        int wflags = __WCLONE;
 
-        CATCH_EINTR(ret = waitpid(pid, NULL, WNOHANG));
+        if (nohang)
+                wflags |= WNOHANG;
+
+        if (!pname)
+                pname = "helper_wait";
+
+        CATCH_EINTR(ret = waitpid(pid, &status, wflags));
         if (ret < 0) {
-                ret = -errno;
-                printk("helper_wait : waitpid failed, errno = %d\n", errno);
-        }
-        return ret;
+                printk(UM_KERN_ERR "%s : waitpid process %d failed, "
+                       "errno = %d\n", pname, pid, errno);
+                return -errno;
+        } else if (nohang && ret == 0) {
+                printk(UM_KERN_ERR "%s : process %d has not exited\n",
+                       pname, pid);
+                return -ECHILD;
+        } else if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
+                printk(UM_KERN_ERR "%s : process %d didn't exit with "
+                       "status 0\n", pname, pid);
+                return -ECHILD;
+        } else
+                return 0;
 }
diff --git a/arch/um/os-Linux/process.c b/arch/um/os-Linux/process.c
index 37781db4ceca..bda5c3150d6c 100644
--- a/arch/um/os-Linux/process.c
+++ b/arch/um/os-Linux/process.c
@@ -101,7 +101,7 @@ void os_kill_process(int pid, int reap_child)
 {
         kill(pid, SIGKILL);
         if (reap_child)
-                CATCH_EINTR(waitpid(pid, NULL, 0));
+                CATCH_EINTR(waitpid(pid, NULL, __WALL));
 }
 
 /* This is here uniquely to have access to the userspace errno, i.e. the one
@@ -130,7 +130,7 @@ void os_kill_ptraced_process(int pid, int reap_child)
         ptrace(PTRACE_KILL, pid);
         ptrace(PTRACE_CONT, pid);
         if (reap_child)
-                CATCH_EINTR(waitpid(pid, NULL, 0));
+                CATCH_EINTR(waitpid(pid, NULL, __WALL));
 }
 
 /* Don't use the glibc version, which caches the result in TLS. It misses some
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index d77c81d7068a..e8b7a97e83d3 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -64,7 +64,7 @@ void wait_stub_done(int pid)
         int n, status, err;
 
         while (1) {
-                CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
+                CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL));
                 if ((n < 0) || !WIFSTOPPED(status))
                         goto bad_wait;
 
@@ -153,7 +153,7 @@ static void handle_trap(int pid, struct uml_pt_regs *regs,
                         panic("handle_trap - continuing to end of syscall "
                               "failed, errno = %d\n", errno);
 
-                CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
+                CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL));
                 if ((err < 0) || !WIFSTOPPED(status) ||
                    (WSTOPSIG(status) != SIGTRAP + 0x80)) {
                         err = ptrace_dump_regs(pid);
@@ -255,16 +255,18 @@ int start_userspace(unsigned long stub_stack)
                 panic("start_userspace : mmap failed, errno = %d", errno);
         sp = (unsigned long) stack + UM_KERN_PAGE_SIZE - sizeof(void *);
 
-        flags = CLONE_FILES | SIGCHLD;
+        flags = CLONE_FILES;
         if (proc_mm)
                 flags |= CLONE_VM;
+        else
+                flags |= SIGCHLD;
 
         pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack);
         if (pid < 0)
                 panic("start_userspace : clone failed, errno = %d", errno);
 
         do {
-                CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
+                CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL));
                 if (n < 0)
                         panic("start_userspace : wait failed, errno = %d",
                               errno);
@@ -314,7 +316,7 @@ void userspace(struct uml_pt_regs *regs)
                               "pid=%d, ptrace operation = %d, errno = %d\n",
                               pid, op, errno);
 
-                CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
+                CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL));
                 if (err < 0)
                         panic("userspace - waitpid failed, errno = %d\n",
                               errno);
diff --git a/arch/um/os-Linux/util.c b/arch/um/os-Linux/util.c
index ef095436a78c..3e058ce9ffb6 100644
--- a/arch/um/os-Linux/util.c
+++ b/arch/um/os-Linux/util.c
@@ -141,7 +141,7 @@ void os_dump_core(void)
          * nothing reasonable to do if that fails.
          */
 
-        while ((pid = waitpid(-1, NULL, WNOHANG)) > 0)
+        while ((pid = waitpid(-1, NULL, WNOHANG | __WALL)) > 0)
                 os_kill_ptraced_process(pid, 0);
 
         abort();