From c6fd91f0bdcd294a0ae0ba2b2a7f7456ef4b7144 Mon Sep 17 00:00:00 2001 From: bibo mao Date: Sun, 26 Mar 2006 01:38:20 -0800 Subject: [PATCH] kretprobe instance recycled by parent process When kretprobe probes the schedule() function, if the probed process exits then schedule() will never return, so some kretprobe instances will never be recycled. In this patch the parent process will recycle retprobe instances of the probed function and there will be no memory leak of kretprobe instances. Signed-off-by: bibo mao Cc: Masami Hiramatsu Cc: Prasanna S Panchamukhi Cc: Ananth N Mavinakayanahalli Cc: Anil S Keshavamurthy Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kprobes.c | 10 +++++----- kernel/sched.c | 9 ++++++++- 2 files changed, 13 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 1fb9f753ef6..1156eb0977d 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -323,10 +323,10 @@ struct hlist_head __kprobes *kretprobe_inst_table_head(struct task_struct *tsk) } /* - * This function is called from exit_thread or flush_thread when task tk's - * stack is being recycled so that we can recycle any function-return probe - * instances associated with this task. These left over instances represent - * probed functions that have been called but will never return. + * This function is called from finish_task_switch when task tk becomes dead, + * so that we can recycle any function-return probe instances associated + * with this task. These left over instances represent probed functions + * that have been called but will never return. */ void __kprobes kprobe_flush_task(struct task_struct *tk) { @@ -336,7 +336,7 @@ void __kprobes kprobe_flush_task(struct task_struct *tk) unsigned long flags = 0; spin_lock_irqsave(&kretprobe_lock, flags); - head = kretprobe_inst_table_head(current); + head = kretprobe_inst_table_head(tk); hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { if (ri->task == tk) recycle_rp_inst(ri); diff --git a/kernel/sched.c b/kernel/sched.c index 7ffaabd64f8..78acdefeccc 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -49,6 +49,7 @@ #include #include #include +#include #include #include @@ -1546,8 +1547,14 @@ static inline void finish_task_switch(runqueue_t *rq, task_t *prev) finish_lock_switch(rq, prev); if (mm) mmdrop(mm); - if (unlikely(prev_task_flags & PF_DEAD)) + if (unlikely(prev_task_flags & PF_DEAD)) { + /* + * Remove function-return probe instances associated with this + * task and put them back on the free list. + */ + kprobe_flush_task(prev); put_task_struct(prev); + } } /** -- cgit v1.2.3-18-g5258