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Subject[tip:perf/core] uprobes: Uprobe_mmap/ munmap needs list_for_each_entry_safe()
Commit-ID:  665605a2a207dbe1fa429b474f932d6ea138ba92
Gitweb: http://git.kernel.org/tip/665605a2a207dbe1fa429b474f932d6ea138ba92
Author: Oleg Nesterov <oleg@redhat.com>
AuthorDate: Sun, 29 Jul 2012 20:22:29 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 30 Jul 2012 11:27:20 +0200

uprobes: Uprobe_mmap/munmap needs list_for_each_entry_safe()

The bug was introduced by me in 449d0d7c ("uprobes: Simplify the
usage of uprobe->pending_list").

Yes, we do not care about uprobe->pending_list after return and
nobody can remove the current list entry, but put_uprobe(uprobe)
can actually free it and thus we need list_for_each_safe().

Reported-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar.vnet.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Link: http://lkml.kernel.org/r/20120729182229.GA20329@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/events/uprobes.c | 8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 5db150b..bed2161 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1010,7 +1010,7 @@ static void build_probe_list(struct inode *inode, struct list_head *head)
int uprobe_mmap(struct vm_area_struct *vma)
{
struct list_head tmp_list;
- struct uprobe *uprobe;
+ struct uprobe *uprobe, *u;
struct inode *inode;
int ret, count;

@@ -1028,7 +1028,7 @@ int uprobe_mmap(struct vm_area_struct *vma)
ret = 0;
count = 0;

- list_for_each_entry(uprobe, &tmp_list, pending_list) {
+ list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) {
if (!ret) {
loff_t vaddr = vma_address(vma, uprobe->offset);

@@ -1076,7 +1076,7 @@ int uprobe_mmap(struct vm_area_struct *vma)
void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end)
{
struct list_head tmp_list;
- struct uprobe *uprobe;
+ struct uprobe *uprobe, *u;
struct inode *inode;

if (!atomic_read(&uprobe_events) || !valid_vma(vma, false))
@@ -1093,7 +1093,7 @@ void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned lon
mutex_lock(uprobes_mmap_hash(inode));
build_probe_list(inode, &tmp_list);

- list_for_each_entry(uprobe, &tmp_list, pending_list) {
+ list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) {
loff_t vaddr = vma_address(vma, uprobe->offset);

if (vaddr >= start && vaddr < end) {

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