Messages in this thread Patch in this message | | | From | Stephen Boyd <> | Subject | [PATCH v2] timers: Provide a better debugobjects hint for delayed works | Date | Wed, 11 May 2022 13:19:51 -0700 |
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With debugobjects enabled the timer hint for freeing of active timers embedded inside delayed works is always the same, i.e. the hint is delayed_work_timer_fn, even though the function the delayed work is going to run can be wildly different depending on what work was queued. Enabling workqueue debugobjects doesn't help either because the delayed work isn't considered active until it is actually queued to run on a workqueue. If the work is freed while the timer is pending the work isn't considered active so we don't get any information from workqueue debugobjects.
Special case delayed works in the timer debugobjects hint logic so that the delayed work function is returned instead of the delayed_work_timer_fn. This will help us understand what delayed work was pending that got freed. Apply the same treatment for kthread_delayed_work because it follows the same pattern.
Cc: Tejun Heo <tj@kernel.org> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Guenter Roeck <groeck@chromium.org> Signed-off-by: Stephen Boyd <swboyd@chromium.org> ---
Feel free to reassign authorship to tglx.
Changes from v1 (https://lore.kernel.org/r/20220504223148.644228-1-swboyd@chromium.org): * Use counter proposed patch from tglx * Deref function pointer to get proper hint * Add 't' the function pointer to make checkpatch quiet
kernel/time/timer.c | 32 +++++++++++++++++++++++++++++++- 1 file changed, 31 insertions(+), 1 deletion(-)
diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 9dd2a39cb3b0..8637990a3842 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -615,9 +615,39 @@ static void internal_add_timer(struct timer_base *base, struct timer_list *timer static const struct debug_obj_descr timer_debug_descr; +struct timer_hint { + void (*function)(struct timer_list *t); + long offset; +}; + +#define TIMER_HINT(fn, container, timr, hintfn) \ + { \ + .function = fn, \ + .offset = offsetof(container, hintfn) - \ + offsetof(container, timr) \ + } + +static const struct timer_hint timer_hints[] = { + TIMER_HINT(delayed_work_timer_fn, + struct delayed_work, timer, work.func), + TIMER_HINT(kthread_delayed_work_timer_fn, + struct kthread_delayed_work, timer, work.func), +}; + static void *timer_debug_hint(void *addr) { - return ((struct timer_list *) addr)->function; + struct timer_list *timer = addr; + int i; + + for (i = 0; i < ARRAY_SIZE(timer_hints); i++) { + if (timer_hints[i].function == timer->function) { + void (**fn)(void) = addr + timer_hints[i].offset; + + return *fn; + } + } + + return timer->function; } static bool timer_is_static_object(void *addr) base-commit: 672c0c5173427e6b3e2a9bbb7be51ceeec78093a -- https://chromeos.dev
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