diff options
Diffstat (limited to 'kernel/livepatch/transition.c')
| -rw-r--r-- | kernel/livepatch/transition.c | 25 |
1 files changed, 9 insertions, 16 deletions
diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c index c53370d596be..cdf318d86dd6 100644 --- a/kernel/livepatch/transition.c +++ b/kernel/livepatch/transition.c @@ -1,20 +1,8 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* * transition.c - Kernel Live Patching transition functions * * Copyright (C) 2015-2016 Josh Poimboeuf <jpoimboe@redhat.com> - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation; either version 2 - * of the License, or (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, see <http://www.gnu.org/licenses/>. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt @@ -259,7 +247,6 @@ static int klp_check_stack(struct task_struct *task, char *err_buf) int ret, nr_entries; ret = stack_trace_save_tsk_reliable(task, entries, ARRAY_SIZE(entries)); - WARN_ON_ONCE(ret == -ENOSYS); if (ret < 0) { snprintf(err_buf, STACK_ERR_BUF_SIZE, "%s: %s:%d has an unreliable stack\n", @@ -293,11 +280,11 @@ static int klp_check_stack(struct task_struct *task, char *err_buf) */ static bool klp_try_switch_task(struct task_struct *task) { + static char err_buf[STACK_ERR_BUF_SIZE]; struct rq *rq; struct rq_flags flags; int ret; bool success = false; - char err_buf[STACK_ERR_BUF_SIZE]; err_buf[0] = '\0'; @@ -306,6 +293,13 @@ static bool klp_try_switch_task(struct task_struct *task) return true; /* + * For arches which don't have reliable stack traces, we have to rely + * on other methods (e.g., switching tasks at kernel exit). + */ + if (!klp_have_reliable_stack()) + return false; + + /* * Now try to check the stack for any to-be-patched or to-be-unpatched * functions. If all goes well, switch the task to the target patch * state. @@ -340,7 +334,6 @@ done: pr_debug("%s", err_buf); return success; - } /* |