Messages in this thread Patch in this message | | | From | (Eric W. Biederman) | Subject | [PATCH] file: Add locking to f_getown | Date | Sat, 09 Sep 2006 22:11:18 -0600 |
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This has been needed for a long time, but now with the advent of a reference counted struct pid there are real consequences for getting this wrong.
Someone I think it was Oleg Nesterov pointed out that this construct was missing locking, when I introduced struct pid. After taking time to review the locking construct already present I figured out which lock needs to be taken. The other paths that access f_owner.pid take either the f_owner read or the write lock.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> --- fs/fcntl.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/fs/fcntl.c b/fs/fcntl.c index 821ebb9..b1dd4d4 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -305,9 +305,11 @@ void f_delown(struct file *filp) pid_t f_getown(struct file *filp) { pid_t pid; + read_lock(&filp->f_owner.lock); pid = pid_nr(filp->f_owner.pid); if (filp->f_owner.pid_type == PIDTYPE_PGID) pid = -pid; + read_unlock(&filp->f_owner.lock); return pid; } -- 1.4.2.rc3.g7e18e-dirty - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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