signal: Simplify and fix kdb_send_sig

- Rename from kdb_send_sig_info to kdb_send_sig
  As there is no meaningful siginfo sent

- Use SEND_SIG_PRIV instead of generating a siginfo for a kdb
  signal.  The generated siginfo had a bogus rationale and was
  not correct in the face of pid namespaces.  SEND_SIG_PRIV
  is simpler and actually correct.

- As the code grabs siglock just send the signal with siglock
  held instead of dropping siglock and attempting to grab it again.

- Move the sig_valid test into kdb_kill where it can generate
  a good error message.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

2 files changed, 3 insertions, 9 deletions

diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
index c8146d53ca67..dbb0781a0533 100644
--- a/kernel/debug/kdb/kdb_main.c
+++ b/kernel/debug/kdb/kdb_main.c
@@ -2441,7 +2441,6 @@ static int kdb_kill(int argc, const char **argv)
         long sig, pid;
         char *endp;
         struct task_struct *p;
-        struct siginfo info;
 
         if (argc != 2)
                 return KDB_ARGCOUNT;
@@ -2449,7 +2448,7 @@ static int kdb_kill(int argc, const char **argv)
         sig = simple_strtol(argv[1], &endp, 0);
         if (*endp)
                 return KDB_BADINT;
-        if (sig >= 0) {
+        if ((sig >= 0) || !valid_signal(-sig)) {
                 kdb_printf("Invalid signal parameter.<-signal>\n");
                 return 0;
         }
@@ -2470,12 +2469,7 @@ static int kdb_kill(int argc, const char **argv)
                 return 0;
         }
         p = p->group_leader;
-        info.si_signo = sig;
-        info.si_errno = 0;
-        info.si_code = SI_USER;
-        info.si_pid = pid;  /* same capabilities as process being signalled */
-        info.si_uid = 0;    /* kdb has root authority */
-        kdb_send_sig_info(p, &info);
+        kdb_send_sig(p, sig);
         return 0;
 }
 
diff --git a/kernel/debug/kdb/kdb_private.h b/kernel/debug/kdb/kdb_private.h
index fc224fbcf954..1e5a502ba4a7 100644
--- a/kernel/debug/kdb/kdb_private.h
+++ b/kernel/debug/kdb/kdb_private.h
@@ -208,7 +208,7 @@ extern unsigned long kdb_task_state(const struct task_struct *p,
 extern void kdb_ps_suppressed(void);
 extern void kdb_ps1(const struct task_struct *p);
 extern void kdb_print_nameval(const char *name, unsigned long val);
-extern void kdb_send_sig_info(struct task_struct *p, struct siginfo *info);
+extern void kdb_send_sig(struct task_struct *p, int sig);
 extern void kdb_meminfo_proc_show(void);
 extern char *kdb_getstr(char *, size_t, const char *);
 extern void kdb_gdb_state_pass(char *buf);