From 1e6cec2253d5159a5f4e758114fd3c26a98b00a4 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Mon, 20 Aug 2012 15:28:00 +0100 Subject: [PATCH] vfs: missed source of ->f_pos races commit 0e665d5d1125f9f4ccff56a75e814f10f88861a2 upstream. compat_sys_{read,write}v() need the same "pass a copy of file->f_pos" thing as sys_{read,write}{,v}(). Signed-off-by: Al Viro Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/compat.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/fs/compat.c b/fs/compat.c index f2944ace7a7b..2b371b38911d 100644 --- a/fs/compat.c +++ b/fs/compat.c @@ -1160,11 +1160,14 @@ compat_sys_readv(unsigned long fd, const struct compat_iovec __user *vec, struct file *file; int fput_needed; ssize_t ret; + loff_t pos; file = fget_light(fd, &fput_needed); if (!file) return -EBADF; - ret = compat_readv(file, vec, vlen, &file->f_pos); + pos = file->f_pos; + ret = compat_readv(file, vec, vlen, &pos); + file->f_pos = pos; fput_light(file, fput_needed); return ret; } @@ -1226,11 +1229,14 @@ compat_sys_writev(unsigned long fd, const struct compat_iovec __user *vec, struct file *file; int fput_needed; ssize_t ret; + loff_t pos; file = fget_light(fd, &fput_needed); if (!file) return -EBADF; - ret = compat_writev(file, vec, vlen, &file->f_pos); + pos = file->f_pos; + ret = compat_writev(file, vec, vlen, &pos); + file->f_pos = pos; fput_light(file, fput_needed); return ret; }