On Thu, 2009-05-07 at 19:59 +0800, Wu Fengguang wrote:
> ---
> inotify: report rounded-up event size to user space
>
> Fix a udev madness problem, which falls into an endless loop:
>
> (1) ppoll([{fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=3, events=POLLIN}], 3, NULL, [], 8) = 1 ([{fd=3, revents=POLLIN}])
> (2) ioctl(3, FIONREAD, [39]) = 0
> (3) read(3, 0x62ad60, 39) = -1 EINVAL (Invalid argument)
>
> In (2) we reported a small len, while in (3) we insist on a rounded up len,
> leading to a failed inotify read(), which will be retried endlessly by udev.
>
> [ 756.569243] get_one_event: event_size=48 > count=38, name_len=22, name=61-dev-root-link.rules
> [ 756.600103] get_one_event: event_size=48 > count=38, name_len=22, name=61-dev-root-link.rules
> [ 756.630265] get_one_event: event_size=48 > count=38, name_len=22, name=61-dev-root-link.rules
> [ 756.670862] get_one_event: event_size=48 > count=38, name_len=22, name=61-dev-root-link.rules
> [ 756.701845] get_one_event: event_size=48 > count=38, name_len=22, name=61-dev-root-link.rules
> [ 756.732899] get_one_event: event_size=48 > count=38, name_len=22, name=61-dev-root-link.rules
> [ 756.763126] get_one_event: event_size=48 > count=38, name_len=22, name=61-dev-root-link.rules
> [ 756.794829] get_one_event: event_size=48 > count=38, name_len=22, name=61-dev-root-link.rules
> [ 756.824985] get_one_event: event_size=48 > count=38, name_len=22, name=61-dev-root-link.rules
> [ 756.856760] get_one_event: event_size=48 > count=38, name_len=22, name=61-dev-root-link.rules
> [ 761.608521] __ratelimit: 210 callbacks suppressed
>
> Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
Gaaah should have remembered to do that with the ioctl.
Acked-by: Eric Paris <eparis@xxxxxxxxxx>
Andrew can you add this to your tree, I will roll it into my next patch
set.
-Eric
> ---
> fs/notify/inotify/inotify_user.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> --- linux.orig/fs/notify/inotify/inotify_user.c
> +++ linux/fs/notify/inotify/inotify_user.c
> @@ -318,7 +318,9 @@ static long inotify_ioctl(struct file *f
> mutex_lock(&group->notification_mutex);
> list_for_each_entry(holder, &group->notification_list, event_list) {
> event = holder->event;
> - send_len += sizeof(struct inotify_event) + event->name_len;
> + send_len += sizeof(struct inotify_event);
> + send_len += roundup(event->name_len,
> + sizeof(struct inotify_event));
> }
> mutex_unlock(&group->notification_mutex);
> ret = put_user(send_len, (int __user *) p);
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