[PATCH 1/5] uprobes: Use a helper instead of ptrace's single step enable

From: Sebastian Andrzej Siewior
Date: Tue Aug 07 2012 - 12:13:03 EST


As Oleg pointed out in [0] utrace should not use the ptrace interface
for enabling/disabling single stepping.

[0] http://lkml.kernel.org/20120730141638.GA5306@xxxxxxxxxx

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
include/linux/uprobes.h | 2 ++
kernel/events/uprobes.c | 14 ++++++++++++--
2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index efe4b33..0fc6585 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -111,6 +111,8 @@ extern void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsig
extern void uprobe_free_utask(struct task_struct *t);
extern void uprobe_copy_process(struct task_struct *t);
extern unsigned long __weak uprobe_get_swbp_addr(struct pt_regs *regs);
+extern void __weak arch_uprobe_enable_step(struct arch_uprobe *arch);
+extern void __weak arch_uprobe_disable_step(struct arch_uprobe *arch);
extern int uprobe_post_sstep_notifier(struct pt_regs *regs);
extern int uprobe_pre_sstep_notifier(struct pt_regs *regs);
extern void uprobe_notify_resume(struct pt_regs *regs);
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index c08a22d..41a2555 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1463,6 +1463,16 @@ static struct uprobe *find_active_uprobe(unsigned long bp_vaddr, int *is_swbp)
return uprobe;
}

+void __weak arch_uprobe_enable_step(struct arch_uprobe *arch)
+{
+ user_enable_single_step(current);
+}
+
+void __weak arch_uprobe_disable_step(struct arch_uprobe *arch)
+{
+ user_disable_single_step(current);
+}
+
/*
* Run handler and ask thread to singlestep.
* Ensure all non-fatal signals cannot interrupt thread while it singlesteps.
@@ -1509,7 +1519,7 @@ static void handle_swbp(struct pt_regs *regs)

utask->state = UTASK_SSTEP;
if (!pre_ssout(uprobe, regs, bp_vaddr)) {
- user_enable_single_step(current);
+ arch_uprobe_enable_step(&uprobe->arch);
return;
}

@@ -1550,7 +1560,7 @@ static void handle_singlestep(struct uprobe_task *utask, struct pt_regs *regs)
put_uprobe(uprobe);
utask->active_uprobe = NULL;
utask->state = UTASK_RUNNING;
- user_disable_single_step(current);
+ arch_uprobe_disable_step(&uprobe->arch);
xol_free_insn_slot(current);

spin_lock_irq(&current->sighand->siglock);
--
1.7.10.4

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