From 6e6abc0339f25e0f45d85fec27aef1e8fe358897 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: Ben Hutchings --- fs/compat.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/fs/compat.c b/fs/compat.c index c98787536bb8..e07a3d3dcd7a 100644 --- a/fs/compat.c +++ b/fs/compat.c @@ -1174,11 +1174,14 @@ 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; } @@ -1233,11 +1236,14 @@ 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; } -- 2.39.2