From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Metcalf Subject: [PATCH v2 3/5] nohz: cpu_isolated strict mode configurable signal Date: Fri, 15 May 2015 17:27:29 -0400 Message-ID: <1431725251-20943-3-git-send-email-cmetcalf@ezchip.com> References: <1431725178-20876-1-git-send-email-cmetcalf@ezchip.com> <1431725251-20943-1-git-send-email-cmetcalf@ezchip.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <1431725251-20943-1-git-send-email-cmetcalf-d5a29ZRxExrQT0dZR+AlfA@public.gmane.org> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Gilad Ben Yossef , Steven Rostedt , Ingo Molnar , Peter Zijlstra , Andrew Morton , Rik van Riel , Tejun Heo , Frederic Weisbecker , Thomas Gleixner , "Paul E. McKenney" , Christoph Lameter , Viresh Kumar , linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: Chris Metcalf List-Id: linux-api@vger.kernel.org Allow userspace to override the default SIGKILL delivered when a cpu_isolated process in STRICT mode does a syscall or otherwise synchronously enters the kernel. In addition to being able to set the signal, we now also pass whether or not the interruption was from a syscall in the si_code field of the siginfo. Signed-off-by: Chris Metcalf --- include/uapi/linux/prctl.h | 2 ++ kernel/time/tick-sched.c | 15 +++++++++++---- 2 files changed, 13 insertions(+), 4 deletions(-) diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index 0c11238a84fb..ab45bd3d5799 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -195,5 +195,7 @@ struct prctl_mm_map { #define PR_GET_CPU_ISOLATED 48 # define PR_CPU_ISOLATED_ENABLE (1 << 0) # define PR_CPU_ISOLATED_STRICT (1 << 1) +# define PR_CPU_ISOLATED_SET_SIG(sig) (((sig) & 0x7f) << 8) +# define PR_CPU_ISOLATED_GET_SIG(bits) (((bits) >> 8) & 0x7f) #endif /* _LINUX_PRCTL_H */ diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 273820cd484a..772be78f926c 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -441,11 +441,18 @@ void tick_nohz_cpu_isolated_enter(void) } } -static void kill_cpu_isolated_strict_task(void) +static void kill_cpu_isolated_strict_task(int is_syscall) { + siginfo_t info = {}; + int sig; + dump_stack(); current->cpu_isolated_flags &= ~PR_CPU_ISOLATED_ENABLE; - send_sig(SIGKILL, current, 1); + + sig = PR_CPU_ISOLATED_GET_SIG(current->cpu_isolated_flags) ?: SIGKILL; + info.si_signo = sig; + info.si_code = is_syscall; + send_sig_info(sig, &info, current); } /* @@ -464,7 +471,7 @@ void tick_nohz_cpu_isolated_syscall(int syscall) pr_warn("%s/%d: cpu_isolated strict mode violated by syscall %d\n", current->comm, current->pid, syscall); - kill_cpu_isolated_strict_task(); + kill_cpu_isolated_strict_task(1); } /* @@ -475,7 +482,7 @@ void tick_nohz_cpu_isolated_exception(void) { pr_warn("%s/%d: cpu_isolated strict mode violated by exception\n", current->comm, current->pid); - kill_cpu_isolated_strict_task(); + kill_cpu_isolated_strict_task(0); } #endif -- 2.1.2