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authorJason Wessel <jason.wessel@windriver.com>2010-05-20 21:04:21 -0500
committerJason Wessel <jason.wessel@windriver.com>2010-05-20 21:04:21 -0500
commit67fc4e0cb931d6b4ccf21248e4199b154478ecea (patch)
tree4cf49d00bc9ac03c3c77d91fadd13fcabc75e0c9 /kernel/signal.c
parent5d5314d6795f3c1c0f415348ff8c51f7de042b77 (diff)
kdb: core for kgdb back end (2 of 2)
This patch contains the hooks and instrumentation into kernel which live outside the kernel/debug directory, which the kdb core will call to run commands like lsmod, dmesg, bt etc... CC: linux-arch@vger.kernel.org Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Martin Hicks <mort@sgi.com>
Diffstat (limited to 'kernel/signal.c')
-rw-r--r--kernel/signal.c40
1 files changed, 40 insertions, 0 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index dbd7fe073c5..825a3f24ad7 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2735,3 +2735,43 @@ void __init signals_init(void)
{
sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
}
+
+#ifdef CONFIG_KGDB_KDB
+#include <linux/kdb.h>
+/*
+ * kdb_send_sig_info - 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)
+{
+ static struct task_struct *kdb_prev_t;
+ int sig, new_t;
+ 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) {
+ kdb_printf("Process is not RUNNING, sending a signal from "
+ "kdb risks deadlock\n"
+ "on the run queue locks. "
+ "The signal has _not_ been sent.\n"
+ "Reissue the kill command if you want to risk "
+ "the deadlock.\n");
+ return;
+ }
+ sig = info->si_signo;
+ if (send_sig_info(sig, info, t))
+ kdb_printf("Fail to deliver Signal %d to process %d.\n",
+ sig, t->pid);
+ else
+ kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
+}
+#endif /* CONFIG_KGDB_KDB */