evie/android_kernel_oneplus_msm8998
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uprobes: Do not allocate current->utask unnecessary

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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: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
This commit is contained in:
Oleg Nesterov 2012-12-31 18:20:42 +01:00
parent aba51024e7
commit 608e7427c0
1 changed files with 6 additions and 10 deletions
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16
kernel/events/uprobes.c
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@ -1308,7 +1308,9 @@ pre_ssout(struct uprobe *uprobe, struct pt_regs *regs, unsigned long bp_vaddr)
unsigned long xol_vaddr; unsigned long xol_vaddr;
int err; int err;
utask = current->utask; utask = get_utask();
if (!utask)
return -ENOMEM;
xol_vaddr = xol_get_insn_slot(uprobe); xol_vaddr = xol_get_insn_slot(uprobe);
if (!xol_vaddr) if (!xol_vaddr)
@ -1323,6 +1325,8 @@ pre_ssout(struct uprobe *uprobe, struct pt_regs *regs, unsigned long bp_vaddr)
return err; return err;
} }
utask->active_uprobe = uprobe;
utask->state = UTASK_SSTEP;
return 0; 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) static void handle_swbp(struct pt_regs *regs)
{ {
struct uprobe_task *utask;
struct uprobe *uprobe; struct uprobe *uprobe;
unsigned long bp_vaddr; unsigned long bp_vaddr;
int uninitialized_var(is_swbp); 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))) if (unlikely(!test_bit(UPROBE_COPY_INSN, &uprobe->flags)))
goto out; goto out;
utask = get_utask();
if (!utask)
goto out; /* re-execute the instruction. */
handler_chain(uprobe, regs); handler_chain(uprobe, regs);
if (can_skip_sstep(uprobe, regs)) if (can_skip_sstep(uprobe, regs))
goto out; goto out;
if (!pre_ssout(uprobe, regs, bp_vaddr)) { if (!pre_ssout(uprobe, regs, bp_vaddr))
utask->active_uprobe = uprobe;
utask->state = UTASK_SSTEP;
return; return;
}
/* can_skip_sstep() succeeded, or restart if can't singlestep */ /* can_skip_sstep() succeeded, or restart if can't singlestep */
out: out: