diff options
author | Jason Wessel <jason.wessel@windriver.com> | 2010-02-12 16:27:58 -0600 |
---|---|---|
committer | Jason Wessel <jason.wessel@windriver.com> | 2010-02-12 16:27:58 -0600 |
commit | 08d1d1b3d5e828e63a9418946ed04bc5204e0f8d (patch) | |
tree | d677f237f7482006597b2dfef5367c4894585ab2 /kernel/signal.c | |
parent | 9d8dc2db21110eb9c2951c1c9502d488b08acf94 (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: mort@sgi.com
CC: linux-arch@vger.kernel.org
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Diffstat (limited to 'kernel/signal.c')
-rw-r--r-- | kernel/signal.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/kernel/signal.c b/kernel/signal.c index 934ae5e687b9..96ecbf8602e2 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2718,3 +2718,43 @@ 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 */ |