| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20250812161755.609600-1-sumanth.gavini@yahoo.com>
Date: Tue, 12 Aug 2025 11:17:54 -0500
From: Sumanth Gavini <sumanth.gavini@...oo.com>
To: rostedt@...dmis.org,
mhiramat@...nel.org,
sumanth.gavini@...oo.com,
tglx@...utronix.de,
jstultz@...gle.com,
clingutla@...eaurora.org,
mingo@...nel.org,
sashal@...nel.org,
boqun.feng@...il.com,
gregkh@...uxfoundation.org,
ryotkkr98@...il.com,
kprateek.nayak@....com
Cc: linux-kernel@...r.kernel.org,
stable@...r.kernel.org,
"J . Avila" <elavila@...gle.com>
Subject: [PATCH 6.1] softirq: Add trace points for tasklet entry/exit
commit f4bf3ca2e5cba655824b6e0893a98dfb33ed24e5 upstream.
Tasklets are supposed to finish their work quickly and should not block the
current running process, but it is not guaranteed that they do so.
Currently softirq_entry/exit can be used to analyse the total tasklets
execution time, but that's not helpful to track individual tasklets
execution time. That makes it hard to identify tasklet functions, which
take more time than expected.
Add tasklet_entry/exit trace point support to track individual tasklet
execution.
Trivial usage example:
# echo 1 > /sys/kernel/debug/tracing/events/irq/tasklet_entry/enable
# echo 1 > /sys/kernel/debug/tracing/events/irq/tasklet_exit/enable
# cat /sys/kernel/debug/tracing/trace
# tracer: nop
#
# entries-in-buffer/entries-written: 4/4 #P:4
#
# _-----=> irqs-off/BH-disabled
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / _-=> migrate-disable
# |||| / delay
# TASK-PID CPU# ||||| TIMESTAMP FUNCTION
# | | | ||||| | |
<idle>-0 [003] ..s1. 314.011428: tasklet_entry: tasklet=0xffffa01ef8db2740 function=tcp_tasklet_func
<idle>-0 [003] ..s1. 314.011432: tasklet_exit: tasklet=0xffffa01ef8db2740 function=tcp_tasklet_func
<idle>-0 [003] ..s1. 314.017369: tasklet_entry: tasklet=0xffffa01ef8db2740 function=tcp_tasklet_func
<idle>-0 [003] ..s1. 314.017371: tasklet_exit: tasklet=0xffffa01ef8db2740 function=tcp_tasklet_func
Signed-off-by: Lingutla Chandrasekhar <clingutla@...eaurora.org>
Signed-off-by: J. Avila <elavila@...gle.com>
Signed-off-by: John Stultz <jstultz@...gle.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Reviewed-by: Steven Rostedt (Google) <rostedt@...dmis.org>
Link: https://lore.kernel.org/r/20230407230526.1685443-1-jstultz@google.com
[elavila: Port to android-mainline]
[jstultz: Rebased to upstream, cut unused trace points, added
comments for the tracepoints, reworded commit]
Signed-off-by: Sumanth Gavini <sumanth.gavini@...oo.com>
---
include/trace/events/irq.h | 47 ++++++++++++++++++++++++++++++++++++++
kernel/softirq.c | 9 ++++++--
2 files changed, 54 insertions(+), 2 deletions(-)
diff --git a/include/trace/events/irq.h b/include/trace/events/irq.h
index eeceafaaea4c..a07b4607b663 100644
--- a/include/trace/events/irq.h
+++ b/include/trace/events/irq.h
@@ -160,6 +160,53 @@ DEFINE_EVENT(softirq, softirq_raise,
TP_ARGS(vec_nr)
);
+DECLARE_EVENT_CLASS(tasklet,
+
+ TP_PROTO(struct tasklet_struct *t, void *func),
+
+ TP_ARGS(t, func),
+
+ TP_STRUCT__entry(
+ __field( void *, tasklet)
+ __field( void *, func)
+ ),
+
+ TP_fast_assign(
+ __entry->tasklet = t;
+ __entry->func = func;
+ ),
+
+ TP_printk("tasklet=%ps function=%ps", __entry->tasklet, __entry->func)
+);
+
+/**
+ * tasklet_entry - called immediately before the tasklet is run
+ * @t: tasklet pointer
+ * @func: tasklet callback or function being run
+ *
+ * Used to find individual tasklet execution time
+ */
+DEFINE_EVENT(tasklet, tasklet_entry,
+
+ TP_PROTO(struct tasklet_struct *t, void *func),
+
+ TP_ARGS(t, func)
+);
+
+/**
+ * tasklet_exit - called immediately after the tasklet is run
+ * @t: tasklet pointer
+ * @func: tasklet callback or function being run
+ *
+ * Used to find individual tasklet execution time
+ */
+DEFINE_EVENT(tasklet, tasklet_exit,
+
+ TP_PROTO(struct tasklet_struct *t, void *func),
+
+ TP_ARGS(t, func)
+);
+
#endif /* _TRACE_IRQ_H */
/* This part must be outside protection */
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 9ab5ca399a99..fadc6bbda27b 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -822,10 +822,15 @@ static void tasklet_action_common(struct softirq_action *a,
if (tasklet_trylock(t)) {
if (!atomic_read(&t->count)) {
if (tasklet_clear_sched(t)) {
- if (t->use_callback)
+ if (t->use_callback) {
+ trace_tasklet_entry(t, t->callback);
t->callback(t);
- else
+ trace_tasklet_exit(t, t->callback);
+ } else {
+ trace_tasklet_entry(t, t->func);
t->func(t->data);
+ trace_tasklet_exit(t, t->func);
+ }
}
tasklet_unlock(t);
continue;
--
2.43.0
Powered by blists - more mailing lists