• Stephen Boyd's avatar
    debugobjects: Print object pointer in debug_print_object() · c4db2d3b
    Stephen Boyd authored
    Delayed kobject debugging (CONFIG_DEBUG_KOBJECT_RELEASE) prints the kobject
    pointer that's being released in kobject_release() before scheduling a
    randomly delayed work to do the actual release work.
    
    If the caller of kobject_put() frees the kobject upon return then this will
    typically emit a debugobject warning about freeing an active timer.
    
    Usually the release function is the function that does the kfree() of the
    struct containing the kobject.
    
    For example the following print is seen
    
     kobject: 'queue' (ffff888114236190): kobject_release, parent 0000000000000000 (delayed 1000)
     ------------[ cut here ]------------
     ODEBUG: free active (active state 0) object type: timer_list hint: kobject_delayed_cleanup+0x0/0x390
    
    but the kobject printk cannot be matched with the debug object printk
    because it could be any number of kobjects that was released around that
    time. The random delay for the work doesn't help either.
    
    Print the address of the object being tracked to help to figure out which
    kobject is the problem here. Note that this does not use %px here to match
    the other %p usage in debugobject debugging. Due to %p usage it is required
    to disable pointer hashing to correlate the two pointer printks.
    Signed-off-by: default avatarStephen Boyd <swboyd@chromium.org>
    Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    Reviewed-by: default avatarGuenter Roeck <linux@roeck-us.net>
    Link: https://lore.kernel.org/r/20220519202201.2348343-1-swboyd@chromium.org
    c4db2d3b
debugobjects.c 35.4 KB