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[PATCH v2 2.6.38-rc8-tip 8/20] 8: uprobes: mmap and fork hooks.
- From: Srikar Dronamraju <srikar at linux dot vnet dot ibm dot com>
- To: Peter Zijlstra <peterz at infradead dot org>, Ingo Molnar <mingo at elte dot hu>
- Cc: Steven Rostedt <rostedt at goodmis dot org>, Srikar Dronamraju <srikar at linux dot vnet dot ibm dot com>, Linux-mm <linux-mm at kvack dot org>, Arnaldo Carvalho de Melo <acme at infradead dot org>, Linus Torvalds <torvalds at linux-foundation dot org>, Masami Hiramatsu <masami dot hiramatsu dot pt at hitachi dot com>, Christoph Hellwig <hch at infradead dot org>, Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, Andi Kleen <andi at firstfloor dot org>, Oleg Nesterov <oleg at redhat dot com>, Andrew Morton <akpm at linux-foundation dot org>, Jim Keniston <jkenisto at linux dot vnet dot ibm dot com>, Roland McGrath <roland at hack dot frob dot com>, SystemTap <systemtap at sources dot redhat dot com>, LKML <linux-kernel at vger dot kernel dot org>, "Paul E. McKenney" <paulmck at linux dot vnet dot ibm dot com>
- Date: Mon, 14 Mar 2011 19:05:36 +0530
- Subject: [PATCH v2 2.6.38-rc8-tip 8/20] 8: uprobes: mmap and fork hooks.
- References: <20110314133403.27435.7901.sendpatchset@localhost6.localdomain6>
Provides hooks in mmap and fork.
On fork, after the new mm is created, we need to set the count of
uprobes. On mmap, check if the mmap region is an executable page and if
its a executable page, walk through the rbtree and insert actual
breakpoints for already registered probes corresponding to this inode.
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
include/linux/uprobes.h | 11 +++++-
kernel/fork.c | 2 +
kernel/uprobes.c | 91 +++++++++++++++++++++++++++++++++++++++++++++++
mm/mmap.c | 2 +
4 files changed, 105 insertions(+), 1 deletions(-)
diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index 8654a06..1f54aae 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -66,6 +66,7 @@ struct uprobe_consumer {
struct uprobe {
struct rb_node rb_node; /* node in the rb tree */
atomic_t ref;
+ struct list_head pending_list;
struct rw_semaphore consumer_rwsem;
struct uprobe_arch_info arch_info; /* arch specific info if any */
struct uprobe_consumer *consumers;
@@ -99,6 +100,10 @@ extern int register_uprobe(struct inode *inode, loff_t offset,
struct uprobe_consumer *consumer);
extern void unregister_uprobe(struct inode *inode, loff_t offset,
struct uprobe_consumer *consumer);
+
+struct vm_area_struct;
+extern void uprobe_mmap(struct vm_area_struct *vma);
+extern void uprobe_dup_mmap(struct mm_struct *old_mm, struct mm_struct *mm);
#else /* CONFIG_UPROBES is not defined */
static inline int register_uprobe(struct inode *inode, loff_t offset,
struct uprobe_consumer *consumer)
@@ -109,6 +114,10 @@ static inline void unregister_uprobe(struct inode *inode, loff_t offset,
struct uprobe_consumer *consumer)
{
}
-
+static inline void uprobe_dup_mmap(struct mm_struct *old_mm,
+ struct mm_struct *mm)
+{
+}
+static inline void uprobe_mmap(struct vm_area_struct *vma) { }
#endif /* CONFIG_UPROBES */
#endif /* _LINUX_UPROBES_H */
diff --git a/kernel/fork.c b/kernel/fork.c
index 25e4291..b6d6877 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -67,6 +67,7 @@
#include <linux/user-return-notifier.h>
#include <linux/oom.h>
#include <linux/khugepaged.h>
+#include <linux/uprobes.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
@@ -418,6 +419,7 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
}
/* a new mm has just been created */
arch_dup_mmap(oldmm, mm);
+ uprobe_dup_mmap(oldmm, mm);
retval = 0;
out:
up_write(&mm->mmap_sem);
diff --git a/kernel/uprobes.c b/kernel/uprobes.c
index 8730633..8ed5b77 100644
--- a/kernel/uprobes.c
+++ b/kernel/uprobes.c
@@ -378,6 +378,7 @@ static struct uprobe *uprobes_add(struct inode *inode, loff_t offset)
}
uprobe->inode = inode;
uprobe->offset = offset;
+ INIT_LIST_HEAD(&uprobe->pending_list);
/* add to uprobes_tree, sorted on inode:offset */
cur_uprobe = insert_uprobe(uprobe);
@@ -715,3 +716,93 @@ put_unlock:
mutex_unlock(&uprobes_mutex);
put_uprobe(uprobe);
}
+
+static void add_to_temp_list(struct vm_area_struct *vma, struct inode *inode,
+ struct list_head *tmp_list)
+{
+ struct uprobe *uprobe;
+ struct rb_node *n;
+ unsigned long flags;
+
+ n = uprobes_tree.rb_node;
+ spin_lock_irqsave(&treelock, flags);
+ uprobe = __find_uprobe(inode, 0, &n);
+ for (; n; n = rb_next(n)) {
+ uprobe = rb_entry(n, struct uprobe, rb_node);
+ if (match_inode(uprobe, inode, &n)) {
+ list_add(&uprobe->pending_list, tmp_list);
+ continue;
+ }
+ break;
+ }
+ spin_unlock_irqrestore(&treelock, flags);
+}
+
+/*
+ * Called from dup_mmap.
+ * called with mm->mmap_sem and old_mm->mmap_sem acquired.
+ */
+void uprobe_dup_mmap(struct mm_struct *old_mm, struct mm_struct *mm)
+{
+ atomic_set(&old_mm->uprobes_count,
+ atomic_read(&mm->uprobes_count));
+}
+
+/*
+ * Called from mmap_region.
+ * called with mm->mmap_sem acquired.
+ */
+void uprobe_mmap(struct vm_area_struct *vma)
+{
+ struct list_head tmp_list;
+ struct uprobe *uprobe, *u;
+ struct mm_struct *mm;
+ struct inode *inode;
+ unsigned long start;
+ unsigned long pgoff;
+
+ if (!valid_vma(vma))
+ return;
+
+ INIT_LIST_HEAD(&tmp_list);
+
+ mm = vma->vm_mm;
+ inode = vma->vm_file->f_mapping->host;
+ start = vma->vm_start;
+ pgoff = vma->vm_pgoff;
+ __iget(inode);
+
+ up_write(&mm->mmap_sem);
+ mutex_lock(&uprobes_mutex);
+ down_read(&mm->mmap_sem);
+
+ vma = find_vma(mm, start);
+ /* Not the same vma */
+ if (!vma || vma->vm_start != start ||
+ vma->vm_pgoff != pgoff || !valid_vma(vma) ||
+ inode->i_mapping != vma->vm_file->f_mapping)
+ goto mmap_out;
+
+ add_to_temp_list(vma, inode, &tmp_list);
+ list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) {
+ loff_t vaddr;
+
+ list_del(&uprobe->pending_list);
+ vaddr = vma->vm_start + uprobe->offset;
+ vaddr -= vma->vm_pgoff << PAGE_SHIFT;
+ if (vaddr > ULONG_MAX)
+ /*
+ * We cannot have a virtual address that is
+ * greater than ULONG_MAX
+ */
+ continue;
+ mm->uprobes_vaddr = (unsigned long)vaddr;
+ install_uprobe(mm, uprobe);
+ }
+
+mmap_out:
+ mutex_unlock(&uprobes_mutex);
+ iput(inode);
+ up_read(&mm->mmap_sem);
+ down_write(&mm->mmap_sem);
+}
diff --git a/mm/mmap.c b/mm/mmap.c
index 2ec8eb5..3836c08 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -30,6 +30,7 @@
#include <linux/perf_event.h>
#include <linux/audit.h>
#include <linux/khugepaged.h>
+#include <linux/uprobes.h>
#include <asm/uaccess.h>
#include <asm/cacheflush.h>
@@ -1366,6 +1367,7 @@ out:
mm->locked_vm += (len >> PAGE_SHIFT);
} else if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK))
make_pages_present(addr, addr + len);
+ uprobe_mmap(vma);
return addr;
unmap_and_free_vma: