epoll: Fix user space breakage related to EPOLLWAKEUP
authorRafael J. Wysocki <rjw@sisk.pl>
Mon, 21 May 2012 19:20:48 +0000 (21:20 +0200)
committerRafael J. Wysocki <rjw@sisk.pl>
Tue, 22 May 2012 18:57:06 +0000 (20:57 +0200)
commita8159414d7e3af7233e7a5a82d1c5d85379bd75c
treead8642afda03a50c2e536afc2ffd906acd44c72c
parent2df83fa4bce421f8176932142f1004adfba0f9dd
epoll: Fix user space breakage related to EPOLLWAKEUP

Commit 4d7e30d (epoll: Add a flag, EPOLLWAKEUP, to prevent
suspend while epoll events are ready) caused some applications to
malfunction, because they set the bit corresponding to the new
EPOLLWAKEUP flag in their eventpoll flags and they don't have the
new CAP_EPOLLWAKEUP capability.

To prevent that from happening, change epoll_ctl() to clear
EPOLLWAKEUP in epds.events if the caller doesn't have the
CAP_EPOLLWAKEUP capability instead of failing and returning an
error code, which allows the affected applications to function
normally.

Reported-and-tested-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
fs/eventpoll.c