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| author | Tejun Heo <tj@kernel.org> | 2012-12-22 01:57:00 (GMT) |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2013-02-09 19:32:42 (GMT) |
| commit | ad72b3bea744b4db01c89af0f86f3e8920d354df (patch) | |
| tree | 8482593d6330783150e88ff7181a1484d3156265 /kernel | |
| parent | 7c99e0bf86fdc1dee238eb6e213b980f887b68f1 (diff) | |
| download | linux-ad72b3bea744b4db01c89af0f86f3e8920d354df.tar.xz | |
kprobes: fix wait_for_kprobe_optimizer()
wait_for_kprobe_optimizer() seems largely broken. It uses
optimizer_comp which is never re-initialized, so
wait_for_kprobe_optimizer() will never wait for anything once
kprobe_optimizer() finishes all pending jobs for the first time.
Also, aside from completion, delayed_work_pending() is %false once
kprobe_optimizer() starts execution and wait_for_kprobe_optimizer()
won't wait for it.
Reimplement it so that it flushes optimizing_work until
[un]optimizing_lists are empty. Note that this also makes
optimizing_work execute immediately if someone's waiting for it, which
is the nicer behavior.
Only compile tested.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/kprobes.c | 23 |
1 files changed, 15 insertions, 8 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 098f396..f230e81 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -471,7 +471,6 @@ static LIST_HEAD(unoptimizing_list); static void kprobe_optimizer(struct work_struct *work); static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer); -static DECLARE_COMPLETION(optimizer_comp); #define OPTIMIZE_DELAY 5 /* @@ -552,8 +551,7 @@ static __kprobes void do_free_cleaned_kprobes(struct list_head *free_list) /* Start optimizer after OPTIMIZE_DELAY passed */ static __kprobes void kick_kprobe_optimizer(void) { - if (!delayed_work_pending(&optimizing_work)) - schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY); + schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY); } /* Kprobe jump optimizer */ @@ -592,16 +590,25 @@ static __kprobes void kprobe_optimizer(struct work_struct *work) /* Step 5: Kick optimizer again if needed */ if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) kick_kprobe_optimizer(); - else - /* Wake up all waiters */ - complete_all(&optimizer_comp); } /* Wait for completing optimization and unoptimization */ static __kprobes void wait_for_kprobe_optimizer(void) { - if (delayed_work_pending(&optimizing_work)) - wait_for_completion(&optimizer_comp); + mutex_lock(&kprobe_mutex); + + while (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) { + mutex_unlock(&kprobe_mutex); + + /* this will also make optimizing_work execute immmediately */ + flush_delayed_work(&optimizing_work); + /* @optimizing_work might not have been queued yet, relax */ + cpu_relax(); + + mutex_lock(&kprobe_mutex); + } + + mutex_unlock(&kprobe_mutex); } /* Optimize kprobe if p is ready to be optimized */ |