Commit a8159414 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki

epoll: Fix user space breakage related to EPOLLWAKEUP

Commit 4d7e30d9 (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: default avatarJiri Slaby <jslaby@suse.cz>
Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
parent 2df83fa4
...@@ -1711,7 +1711,7 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd, ...@@ -1711,7 +1711,7 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd,
/* Check if EPOLLWAKEUP is allowed */ /* Check if EPOLLWAKEUP is allowed */
if ((epds.events & EPOLLWAKEUP) && !capable(CAP_EPOLLWAKEUP)) if ((epds.events & EPOLLWAKEUP) && !capable(CAP_EPOLLWAKEUP))
goto error_tgt_fput; epds.events &= ~EPOLLWAKEUP;
/* /*
* We have to check that the file structure underneath the file descriptor * We have to check that the file structure underneath the file descriptor
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment