> -procfs-fix-race-between-proc_readdir-and-remove_proc_entry.patch
> +fix-race-between-proc_get_inode-and-remove_proc_entry.patch
>
>  Updated.  Looks sane.

Why have you dropped the first patch? Resending slightly fixed version
of it.


[PATCH -mm] Fix race between proc_readdir and remove_proc_entry

From: "Darrick J. Wong" <[EMAIL PROTECTED]>

Fix the following race:

proc_readdir                            remove_proc_entry
============                            =================

spin_lock(&proc_subdir_lock);
[choose PDE to start filldir from]
spin_unlock(&proc_subdir_lock);
                                        spin_lock(&proc_subdir_lock);
                                        [find PDE]
                                        [free PDE, refcount is 0]
                                        spin_unlock(&proc_subdir_lock);
                    /* boom */
if (filldir(dirent, de->name, ...

[de_put on error path --adobriyan]

Signed-off-by: Darrick J. Wong <[EMAIL PROTECTED]>
Signed-off-by: Alexey Dobriyan <[EMAIL PROTECTED]>
---

 fs/proc/generic.c |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -478,14 +478,21 @@ int proc_readdir(struct file * filp,
                        }
 
                        do {
+                               struct proc_dir_entry *next;
+
                                /* filldir passes info to user space */
+                               de_get(de);
                                spin_unlock(&proc_subdir_lock);
                                if (filldir(dirent, de->name, de->namelen, 
filp->f_pos,
-                                           de->low_ino, de->mode >> 12) < 0)
+                                           de->low_ino, de->mode >> 12) < 0) {
+                                       de_put(de);
                                        goto out;
+                               }
                                spin_lock(&proc_subdir_lock);
                                filp->f_pos++;
-                               de = de->next;
+                               next = de->next;
+                               de_put(de);
+                               de = next;
                        } while (de);
                        spin_unlock(&proc_subdir_lock);
        }

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to