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uprobes: Kill UPROBE_RUN_HANDLER flag

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Simply remove UPROBE_RUN_HANDLER and the corresponding code.

It can only help if uprobe has a single consumer, and in fact
it is no longer needed after handler_chain() was changed to use
->register_rwsem, we simply can not race with uprobe_register().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
This commit is contained in:
Oleg Nesterov 2012-11-24 18:27:08 +01:00
parent 1ff6fee5e6
commit bb929284be
1 changed files with 5 additions and 18 deletions
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23
kernel/events/uprobes.c
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@ -83,10 +83,8 @@ static atomic_t uprobe_events = ATOMIC_INIT(0);
/* Have a copy of original instruction */
#define UPROBE_COPY_INSN 0
/* Dont run handlers when first register/ last unregister in progress*/
#define UPROBE_RUN_HANDLER 1
/* Can skip singlestep */
#define UPROBE_SKIP_SSTEP 2
#define UPROBE_SKIP_SSTEP 1
struct uprobe {
struct rb_node rb_node; /* node in the rb tree */
@ -475,9 +473,6 @@ static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs)
{
struct uprobe_consumer *uc;
if (!test_bit(UPROBE_RUN_HANDLER, &uprobe->flags))
return;
down_read(&uprobe->register_rwsem);
for (uc = uprobe->consumers; uc; uc = uc->next)
uc->handler(uc, regs);
@ -825,13 +820,8 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
static int __uprobe_register(struct uprobe *uprobe, struct uprobe_consumer *uc)
{
int err;
consumer_add(uprobe, uc);
err = register_for_each_vma(uprobe, true);
if (!err) /* TODO: pointless unless the first consumer */
set_bit(UPROBE_RUN_HANDLER, &uprobe->flags);
return err;
return register_for_each_vma(uprobe, true);
}
static void __uprobe_unregister(struct uprobe *uprobe, struct uprobe_consumer *uc)
@ -842,12 +832,9 @@ static void __uprobe_unregister(struct uprobe *uprobe, struct uprobe_consumer *u
return;
err = register_for_each_vma(uprobe, false);
if (!uprobe->consumers) {
clear_bit(UPROBE_RUN_HANDLER, &uprobe->flags);
/* TODO : cant unregister? schedule a worker thread */
if (!err)
delete_uprobe(uprobe);
}
/* TODO : cant unregister? schedule a worker thread */
if (!uprobe->consumers && !err)
delete_uprobe(uprobe);
}
/*