From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [PATCH 17/30] tracing: Improve panic/die notifiers References: <20220427224924.592546-1-gpiccoli@igalia.com> <20220427224924.592546-18-gpiccoli@igalia.com> From: Sergei Shtylyov Message-ID: Date: Fri, 29 Apr 2022 12:22:44 +0300 MIME-Version: 1.0 In-Reply-To: <20220427224924.592546-18-gpiccoli@igalia.com> Content-Language: en-US List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-um" Errors-To: linux-um-bounces+geert=linux-m68k.org@lists.infradead.org To: "Guilherme G. Piccoli" , akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org Hello! On 4/28/22 1:49 AM, Guilherme G. Piccoli wrote: > Currently the tracing dump_on_oops feature is implemented > through separate notifiers, one for die/oops and the other > for panic. With the addition of panic notifier "id", this > patch makes use of such "id" to unify both functions. > > It also comments the function and changes the priority of the > notifier blocks, in order they run early compared to other > notifiers, to prevent useless trace data (like the callback > names for the other notifiers). Finally, we also removed an > unnecessary header inclusion. > > Signed-off-by: Guilherme G. Piccoli > --- > kernel/trace/trace.c | 57 +++++++++++++++++++++++++------------------- > 1 file changed, 32 insertions(+), 25 deletions(-) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index f4de111fa18f..c1d8a3622ccc 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c [...] > @@ -9767,38 +9766,46 @@ static __init int tracer_init_tracefs(void) > > fs_initcall(tracer_init_tracefs); > > -static int trace_panic_handler(struct notifier_block *this, > - unsigned long event, void *unused) > +/* > + * The idea is to execute the following die/panic callback early, in order > + * to avoid showing irrelevant information in the trace (like other panic > + * notifier functions); we are the 2nd to run, after hung_task/rcu_stall > + * warnings get disabled (to prevent potential log flooding). > + */ > +static int trace_die_panic_handler(struct notifier_block *self, > + unsigned long ev, void *unused) > { > - if (ftrace_dump_on_oops) > + int do_dump; bool? > + > + if (!ftrace_dump_on_oops) > + return NOTIFY_DONE; > + > + switch (ev) { > + case DIE_OOPS: > + do_dump = 1; > + break; > + case PANIC_NOTIFIER: > + do_dump = 1; > + break; Why not: case DIE_OOPS: case PANIC_NOTIFIER: do_dump = 1; break; > + default: > + do_dump = 0; > + break; > + } > + > + if (do_dump) > ftrace_dump(ftrace_dump_on_oops); > - return NOTIFY_OK; > + > + return NOTIFY_DONE; > } [...] MBR, Sergey _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um