Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933254AbeALBBX (ORCPT + 1 other); Thu, 11 Jan 2018 20:01:23 -0500 Received: from out01.mta.xmission.com ([166.70.13.231]:35517 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932471AbeALBBQ (ORCPT ); Thu, 11 Jan 2018 20:01:16 -0500 From: "Eric W. Biederman" To: linux-kernel@vger.kernel.org Cc: Al Viro , Oleg Nesterov , linux-arch@vger.kernel.org, "Eric W. Biederman" Date: Thu, 11 Jan 2018 18:59:30 -0600 Message-Id: <20180112005940.23279-1-ebiederm@xmission.com> X-Mailer: git-send-email 2.14.1 In-Reply-To: <87373b6ghs.fsf@xmission.com> References: <87373b6ghs.fsf@xmission.com> X-XM-SPF: eid=1eZnic-00053y-VZ;;;mid=<20180112005940.23279-1-ebiederm@xmission.com>;;;hst=in01.mta.xmission.com;;;ip=97.121.73.102;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX1/8tE2Rr3zRpUp64LP7GG35GCdOp+XUHD8= X-SA-Exim-Connect-IP: 97.121.73.102 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: [PATCH 01/11] signal: Simplify and fix kdb_send_sig X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: - 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 --- kernel/debug/kdb/kdb_main.c | 10 ++-------- kernel/debug/kdb/kdb_private.h | 2 +- kernel/signal.c | 14 +++++++------- 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 /* - * 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 -- 2.14.1