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-rw-r--r--include/linux/uprobes.h8
-rw-r--r--kernel/events/uprobes.c26
-rw-r--r--kernel/fork.c2
3 files changed, 33 insertions, 3 deletions
diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index 2615c4d7788d..4f628a6fc5b4 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -97,6 +97,8 @@ extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_con
extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);
extern int uprobe_mmap(struct vm_area_struct *vma);
extern void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end);
+extern void uprobe_start_dup_mmap(void);
+extern void uprobe_end_dup_mmap(void);
extern void uprobe_dup_mmap(struct mm_struct *oldmm, struct mm_struct *newmm);
extern void uprobe_free_utask(struct task_struct *t);
extern void uprobe_copy_process(struct task_struct *t);
@@ -127,6 +129,12 @@ static inline void
uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end)
{
}
+static inline void uprobe_start_dup_mmap(void)
+{
+}
+static inline void uprobe_end_dup_mmap(void)
+{
+}
static inline void
uprobe_dup_mmap(struct mm_struct *oldmm, struct mm_struct *newmm)
{
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 5ce99cfd2e6e..dea7acfbb071 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -33,6 +33,7 @@
#include <linux/ptrace.h> /* user_enable_single_step */
#include <linux/kdebug.h> /* notifier mechanism */
#include "../../mm/internal.h" /* munlock_vma_page */
+#include <linux/percpu-rwsem.h>
#include <linux/uprobes.h>
@@ -71,6 +72,8 @@ static struct mutex uprobes_mutex[UPROBES_HASH_SZ];
static struct mutex uprobes_mmap_mutex[UPROBES_HASH_SZ];
#define uprobes_mmap_hash(v) (&uprobes_mmap_mutex[((unsigned long)(v)) % UPROBES_HASH_SZ])
+static struct percpu_rw_semaphore dup_mmap_sem;
+
/*
* uprobe_events allows us to skip the uprobe_mmap if there are no uprobe
* events active at this time. Probably a fine grained per inode count is
@@ -766,10 +769,13 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
struct map_info *info;
int err = 0;
+ percpu_down_write(&dup_mmap_sem);
info = build_map_info(uprobe->inode->i_mapping,
uprobe->offset, is_register);
- if (IS_ERR(info))
- return PTR_ERR(info);
+ if (IS_ERR(info)) {
+ err = PTR_ERR(info);
+ goto out;
+ }
while (info) {
struct mm_struct *mm = info->mm;
@@ -799,7 +805,8 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
mmput(mm);
info = free_map_info(info);
}
-
+ out:
+ percpu_up_write(&dup_mmap_sem);
return err;
}
@@ -1131,6 +1138,16 @@ void uprobe_clear_state(struct mm_struct *mm)
kfree(area);
}
+void uprobe_start_dup_mmap(void)
+{
+ percpu_down_read(&dup_mmap_sem);
+}
+
+void uprobe_end_dup_mmap(void)
+{
+ percpu_up_read(&dup_mmap_sem);
+}
+
void uprobe_dup_mmap(struct mm_struct *oldmm, struct mm_struct *newmm)
{
newmm->uprobes_state.xol_area = NULL;
@@ -1597,6 +1614,9 @@ static int __init init_uprobes(void)
mutex_init(&uprobes_mmap_mutex[i]);
}
+ if (percpu_init_rwsem(&dup_mmap_sem))
+ return -ENOMEM;
+
return register_die_notifier(&uprobe_exception_nb);
}
module_init(init_uprobes);
diff --git a/kernel/fork.c b/kernel/fork.c
index 8b20ab7d3aa2..c497e57aa654 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -352,6 +352,7 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
unsigned long charge;
struct mempolicy *pol;
+ uprobe_start_dup_mmap();
down_write(&oldmm->mmap_sem);
flush_cache_dup_mm(oldmm);
uprobe_dup_mmap(oldmm, mm);
@@ -469,6 +470,7 @@ out:
up_write(&mm->mmap_sem);
flush_tlb_mm(oldmm);
up_write(&oldmm->mmap_sem);
+ uprobe_end_dup_mmap();
return retval;
fail_nomem_anon_vma_fork:
mpol_put(pol);