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authorEric W. Biederman <ebiederm@xmission.com>2017-08-17 15:45:38 -0500
committerEric W. Biederman <ebiederm@xmission.com>2018-01-03 18:01:08 -0600
commit0b44bf9a6f5cde099ae21b4aa94553484203769a (patch)
tree4563f1383ab50d592b8c09ec451121d5fccfdd09
parent30a7acd573899fd8b8ac39236eff6468b195ac7d (diff)
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>
-rw-r--r--kernel/debug/kdb/kdb_main.c10
-rw-r--r--kernel/debug/kdb/kdb_private.h2
-rw-r--r--kernel/signal.c14
3 files changed, 10 insertions, 16 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);
diff --git a/kernel/signal.c b/kernel/signal.c
index 9558664bd9ec..c894162ec96c 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3684,26 +3684,25 @@ void __init signals_init(void)
#ifdef CONFIG_KGDB_KDB
#include <linux/kdb.h>
/*
- * kdb_send_sig_info - Allows kdb to send signals without exposing
+ * kdb_send_sig - Allows kdb to send signals without exposing
* signal internals. This function checks if the required locks are
* available before calling the main signal code, to avoid kdb
* deadlocks.
*/
-void
-kdb_send_sig_info(struct task_struct *t, struct siginfo *info)
+void kdb_send_sig(struct task_struct *t, int sig)
{
static struct task_struct *kdb_prev_t;
- int sig, new_t;
+ int new_t, ret;
if (!spin_trylock(&t->sighand->siglock)) {
kdb_printf("Can't do kill command now.\n"
"The sigmask lock is held somewhere else in "
"kernel, try again later\n");
return;
}
- spin_unlock(&t->sighand->siglock);
new_t = kdb_prev_t != t;
kdb_prev_t = t;
if (t->state != TASK_RUNNING && new_t) {
+ spin_unlock(&t->sighand->siglock);
kdb_printf("Process is not RUNNING, sending a signal from "
"kdb risks deadlock\n"
"on the run queue locks. "
@@ -3712,8 +3711,9 @@ kdb_send_sig_info(struct task_struct *t, struct siginfo *info)
"the deadlock.\n");
return;
}
- sig = info->si_signo;
- if (send_sig_info(sig, info, t))
+ ret = send_signal(sig, SEND_SIG_PRIV, t, false);
+ spin_unlock(&t->sighand->siglock);
+ if (ret)
kdb_printf("Fail to deliver Signal %d to process %d.\n",
sig, t->pid);
else

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