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| author | Renaud Lottiaux <renaud.lottiaux@kerlabs.com> | 2009-06-30 11:41:34 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-07-02 16:41:00 -0700 |
| commit | be5583f5440217b114eb0a0c172d85d92d86dfbb (patch) | |
| tree | 4ed3f670910d14cd7b3fc68cba9dd1868b7e54ec | |
| parent | 57b70321247d5decb480a8344c29ab5813901790 (diff) | |
| download | lwn-be5583f5440217b114eb0a0c172d85d92d86dfbb.tar.gz lwn-be5583f5440217b114eb0a0c172d85d92d86dfbb.zip | |
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.c | 6 |
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; |