From 2bb5e840e873f8778a41801141771f54f547fa65 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 21 Jul 2015 15:40:06 +0200 Subject: [PATCH] uprobes: Introduce free_ret_instance() We can simplify uprobe_free_utask() and handle_uretprobe_chain() if we add a simple helper which does put_uprobe/kfree and returns the ->next return_instance. Tested-by: Pratyush Anand Signed-off-by: Oleg Nesterov Acked-by: Srikar Dronamraju Acked-by: Anton Arapov Cc: Andy Lutomirski Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20150721134006.GA4740@redhat.com Signed-off-by: Ingo Molnar --- kernel/events/uprobes.c | 27 +++++++++++++-------------- 1 file changed, 13 insertions(+), 14 deletions(-) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index a9847b4ec1e7..d8c702fc836f 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1378,6 +1378,14 @@ unsigned long uprobe_get_trap_addr(struct pt_regs *regs) return instruction_pointer(regs); } +static struct return_instance *free_ret_instance(struct return_instance *ri) +{ + struct return_instance *next = ri->next; + put_uprobe(ri->uprobe); + kfree(ri); + return next; +} + /* * Called with no locks held. * Called in context of a exiting or a exec-ing thread. @@ -1385,7 +1393,7 @@ unsigned long uprobe_get_trap_addr(struct pt_regs *regs) void uprobe_free_utask(struct task_struct *t) { struct uprobe_task *utask = t->utask; - struct return_instance *ri, *tmp; + struct return_instance *ri; if (!utask) return; @@ -1394,13 +1402,8 @@ void uprobe_free_utask(struct task_struct *t) put_uprobe(utask->active_uprobe); ri = utask->return_instances; - while (ri) { - tmp = ri; - ri = ri->next; - - put_uprobe(tmp->uprobe); - kfree(tmp); - } + while (ri) + ri = free_ret_instance(ri); xol_free_insn_slot(t); kfree(utask); @@ -1770,7 +1773,7 @@ handle_uretprobe_chain(struct return_instance *ri, struct pt_regs *regs) static bool handle_trampoline(struct pt_regs *regs) { struct uprobe_task *utask; - struct return_instance *ri, *tmp; + struct return_instance *ri; bool chained; utask = current->utask; @@ -1792,11 +1795,7 @@ static bool handle_trampoline(struct pt_regs *regs) handle_uretprobe_chain(ri, regs); chained = ri->chained; - put_uprobe(ri->uprobe); - - tmp = ri; - ri = ri->next; - kfree(tmp); + ri = free_ret_instance(ri); utask->depth--; if (!chained) -- 2.20.1