Commit 608e7427 authored by Oleg Nesterov's avatar Oleg Nesterov
Browse files

uprobes: Do not allocate current->utask unnecessary 



handle_swbp() does get_utask() before can_skip_sstep() for no reason,
we do not need ->utask if can_skip_sstep() succeeds.

Move get_utask() to pre_ssout() who actually starts to use it. Move
the initialization of utask->active_uprobe/state as well. This way
the whole initialization is consolidated in pre_ssout().

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Acked-by: default avatarAnton Arapov <anton@redhat.com>
parent aba51024

kernel/events/uprobes.c

+6 −10
Original line number Diff line number Diff line
@@ -1308,7 +1308,9 @@ pre_ssout(struct uprobe *uprobe, struct pt_regs *regs, unsigned long bp_vaddr) 
	unsigned long xol_vaddr;

	int err;



	utask = current->utask;

	utask = get_utask();

	if (!utask)

		return -ENOMEM;



	xol_vaddr = xol_get_insn_slot(uprobe);

	if (!xol_vaddr)
@@ -1323,6 +1325,8 @@ pre_ssout(struct uprobe *uprobe, struct pt_regs *regs, unsigned long bp_vaddr) 
		return err;

	}



	utask->active_uprobe = uprobe;

	utask->state = UTASK_SSTEP;

	return 0;

}
@@ -1474,7 +1478,6 @@ static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs) 
 */

static void handle_swbp(struct pt_regs *regs)

{

	struct uprobe_task *utask;

	struct uprobe *uprobe;

	unsigned long bp_vaddr;

	int uninitialized_var(is_swbp);
@@ -1512,19 +1515,12 @@ static void handle_swbp(struct pt_regs *regs) 
	if (unlikely(!test_bit(UPROBE_COPY_INSN, &uprobe->flags)))

		goto out;



	utask = get_utask();

	if (!utask)

		goto out;	/* re-execute the instruction. */



	handler_chain(uprobe, regs);

	if (can_skip_sstep(uprobe, regs))

		goto out;



	if (!pre_ssout(uprobe, regs, bp_vaddr)) {

		utask->active_uprobe = uprobe;

		utask->state = UTASK_SSTEP;

	if (!pre_ssout(uprobe, regs, bp_vaddr))

		return;

	}



	/* can_skip_sstep() succeeded, or restart if can't singlestep */

out:

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