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authorRenaud Lottiaux <renaud.lottiaux@kerlabs.com>2009-06-30 11:41:34 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2009-07-02 16:51:07 -0700
commit114612139b431f6e908dc3c4f78f4dde62310155 (patch)
tree073939a36b6cc95665b84d825e39cd4fe926855e
parent6e9b0f6d101c80eb88a648d6746031ca77043043 (diff)
bsdacct: fix access to invalid filp in acct_on()
commit df279ca8966c3de83105428e3391ab17690802a9 upstream. The file opened in acct_on and freshly stored in the ns->bacct struct can be closed in acct_file_reopen by a concurrent call after we release acct_lock and before we call mntput(file->f_path.mnt). Record file->f_path.mnt in a local variable and use this variable only. Signed-off-by: Renaud Lottiaux <renaud.lottiaux@kerlabs.com> Signed-off-by: Louis Rilling <louis.rilling@kerlabs.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--kernel/acct.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/acct.c b/kernel/acct.c
index 7afa31564162..9f3391090b3e 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -215,6 +215,7 @@ static void acct_file_reopen(struct bsd_acct_struct *acct, struct file *file,
static int acct_on(char *name)
{
struct file *file;
+ struct vfsmount *mnt;
int error;
struct pid_namespace *ns;
struct bsd_acct_struct *acct = NULL;
@@ -256,11 +257,12 @@ static int acct_on(char *name)
acct = NULL;
}
- mnt_pin(file->f_path.mnt);
+ mnt = file->f_path.mnt;
+ mnt_pin(mnt);
acct_file_reopen(ns->bacct, file, ns);
spin_unlock(&acct_lock);
- mntput(file->f_path.mnt); /* it's pinned, now give up active reference */
+ mntput(mnt); /* it's pinned, now give up active reference */
kfree(acct);
return 0;