On Tue, Aug 12, 2025 at 11:17:54AM -0500, Sumanth Gavini wrote:
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@codeaurora.org Signed-off-by: J. Avila elavila@google.com Signed-off-by: John Stultz jstultz@google.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Reviewed-by: Steven Rostedt (Google) rostedt@goodmis.org Link: https://lore.kernel.org/r/20230407230526.1685443-1-jstultz@google.com
[elavila: Port to android-mainline]
This is not android-mainline, this is the normal stable tree.
And I'm with John, this makes no sense as to why you need/want these. I think that the syzbot report is bogus, sorry. Please prove me wrong :)
thanks,
greg k-h