lkml.org 
[lkml]   [2011]   [Nov]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[tip:core/debugobjects] timer: Use debugobjects to catch deletion of uninitialized timers
    Commit-ID:  dc4218bd0fe499fce2896f88101ea42dac1f60fc
    Gitweb: http://git.kernel.org/tip/dc4218bd0fe499fce2896f88101ea42dac1f60fc
    Author: Christine Chan <cschan@codeaurora.org>
    AuthorDate: Mon, 7 Nov 2011 19:48:28 -0800
    Committer: Thomas Gleixner <tglx@linutronix.de>
    CommitDate: Wed, 23 Nov 2011 18:49:23 +0100

    timer: Use debugobjects to catch deletion of uninitialized timers

    del_timer_sync() calls debug_object_assert_init() to assert that
    a timer has been initialized before calling lock_timer_base().
    lock_timer_base() would spin forever on a NULL(uninit-ed) base.
    The check is added to del_timer() to prevent silent failure, even
    though it would not get stuck in an infinite loop.

    [ sboyd@codeaurora.org: Remove WARN, intialize timer function]

    Signed-off-by: Christine Chan <cschan@codeaurora.org>
    Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
    Cc: John Stultz <john.stultz@linaro.org>
    Link: http://lkml.kernel.org/r/1320724108-20788-4-git-send-email-sboyd@codeaurora.org
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    ---
    kernel/timer.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++-----
    1 files changed, 48 insertions(+), 5 deletions(-)

    diff --git a/kernel/timer.c b/kernel/timer.c
    index 317087d..5fc5a76 100644
    --- a/kernel/timer.c
    +++ b/kernel/timer.c
    @@ -487,12 +487,40 @@ static int timer_fixup_free(void *addr, enum debug_obj_state state)
    }
    }

    +/*
    + * fixup_assert_init is called when:
    + * - an untracked/uninit-ed object is found
    + */
    +static int timer_fixup_assert_init(void *addr, enum debug_obj_state state)
    +{
    + struct timer_list *timer = addr;
    +
    + switch (state) {
    + case ODEBUG_STATE_NOTAVAILABLE:
    + if (timer->entry.prev == TIMER_ENTRY_STATIC) {
    + /*
    + * This is not really a fixup. The timer was
    + * statically initialized. We just make sure that it
    + * is tracked in the object tracker.
    + */
    + debug_object_init(timer, &timer_debug_descr);
    + return 0;
    + } else {
    + setup_timer(timer, stub_timer, 0);
    + return 1;
    + }
    + default:
    + return 0;
    + }
    +}
    +
    static struct debug_obj_descr timer_debug_descr = {
    - .name = "timer_list",
    - .debug_hint = timer_debug_hint,
    - .fixup_init = timer_fixup_init,
    - .fixup_activate = timer_fixup_activate,
    - .fixup_free = timer_fixup_free,
    + .name = "timer_list",
    + .debug_hint = timer_debug_hint,
    + .fixup_init = timer_fixup_init,
    + .fixup_activate = timer_fixup_activate,
    + .fixup_free = timer_fixup_free,
    + .fixup_assert_init = timer_fixup_assert_init,
    };

    static inline void debug_timer_init(struct timer_list *timer)
    @@ -515,6 +543,11 @@ static inline void debug_timer_free(struct timer_list *timer)
    debug_object_free(timer, &timer_debug_descr);
    }

    +static inline void debug_timer_assert_init(struct timer_list *timer)
    +{
    + debug_object_assert_init(timer, &timer_debug_descr);
    +}
    +
    static void __init_timer(struct timer_list *timer,
    const char *name,
    struct lock_class_key *key);
    @@ -538,6 +571,7 @@ EXPORT_SYMBOL_GPL(destroy_timer_on_stack);
    static inline void debug_timer_init(struct timer_list *timer) { }
    static inline void debug_timer_activate(struct timer_list *timer) { }
    static inline void debug_timer_deactivate(struct timer_list *timer) { }
    +static inline void debug_timer_assert_init(struct timer_list *timer) { }
    #endif

    static inline void debug_init(struct timer_list *timer)
    @@ -559,6 +593,11 @@ static inline void debug_deactivate(struct timer_list *timer)
    trace_timer_cancel(timer);
    }

    +static inline void debug_assert_init(struct timer_list *timer)
    +{
    + debug_timer_assert_init(timer);
    +}
    +
    static void __init_timer(struct timer_list *timer,
    const char *name,
    struct lock_class_key *key)
    @@ -909,6 +948,8 @@ int del_timer(struct timer_list *timer)
    unsigned long flags;
    int ret = 0;

    + debug_assert_init(timer);
    +
    timer_stats_timer_clear_start_info(timer);
    if (timer_pending(timer)) {
    base = lock_timer_base(timer, &flags);
    @@ -939,6 +980,8 @@ int try_to_del_timer_sync(struct timer_list *timer)
    unsigned long flags;
    int ret = -1;

    + debug_assert_init(timer);
    +
    base = lock_timer_base(timer, &flags);

    if (base->running_timer == timer)

    \
     
     \ /
      Last update: 2011-11-28 15:23    [W:0.051 / U:2.000 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site