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Diffstat (limited to 'arch/x86/kernel/ptrace.c')
-rw-r--r--arch/x86/kernel/ptrace.c45
1 files changed, 34 insertions, 11 deletions
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 6ad2bb60765..0a5df5f82fb 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -650,6 +650,24 @@ static int ptrace_bts_drain(struct task_struct *child,
return drained;
}
+static int ptrace_bts_allocate_buffer(struct task_struct *child, size_t size)
+{
+ child->bts_buffer = alloc_locked_buffer(size);
+ if (!child->bts_buffer)
+ return -ENOMEM;
+
+ child->bts_size = size;
+
+ return 0;
+}
+
+static void ptrace_bts_free_buffer(struct task_struct *child)
+{
+ free_locked_buffer(child->bts_buffer, child->bts_size);
+ child->bts_buffer = NULL;
+ child->bts_size = 0;
+}
+
static int ptrace_bts_config(struct task_struct *child,
long cfg_size,
const struct ptrace_bts_config __user *ucfg)
@@ -679,14 +697,13 @@ static int ptrace_bts_config(struct task_struct *child,
if ((cfg.flags & PTRACE_BTS_O_ALLOC) &&
(cfg.size != child->bts_size)) {
- kfree(child->bts_buffer);
+ int error;
- child->bts_size = cfg.size;
- child->bts_buffer = kzalloc(cfg.size, GFP_KERNEL);
- if (!child->bts_buffer) {
- child->bts_size = 0;
- return -ENOMEM;
- }
+ ptrace_bts_free_buffer(child);
+
+ error = ptrace_bts_allocate_buffer(child, cfg.size);
+ if (error < 0)
+ return error;
}
if (cfg.flags & PTRACE_BTS_O_TRACE)
@@ -701,10 +718,8 @@ static int ptrace_bts_config(struct task_struct *child,
if (IS_ERR(child->bts)) {
int error = PTR_ERR(child->bts);
- kfree(child->bts_buffer);
+ ptrace_bts_free_buffer(child);
child->bts = NULL;
- child->bts_buffer = NULL;
- child->bts_size = 0;
return error;
}
@@ -784,6 +799,9 @@ static void ptrace_bts_untrace(struct task_struct *child)
ds_release_bts(child->bts);
child->bts = NULL;
+ /* We cannot update total_vm and locked_vm since
+ child's mm is already gone. But we can reclaim the
+ memory. */
kfree(child->bts_buffer);
child->bts_buffer = NULL;
child->bts_size = 0;
@@ -792,7 +810,12 @@ static void ptrace_bts_untrace(struct task_struct *child)
static void ptrace_bts_detach(struct task_struct *child)
{
- ptrace_bts_untrace(child);
+ if (unlikely(child->bts)) {
+ ds_release_bts(child->bts);
+ child->bts = NULL;
+
+ ptrace_bts_free_buffer(child);
+ }
}
#else
static inline void ptrace_bts_fork(struct task_struct *tsk) {}