On 06/25, Oleg Nesterov wrote:
>
> But if we remove this WARN_ON() we can probably change
> set_restore_sigmask() to set TS_RESTORE_SIGMASK and
> do saved_mask = blocked.
>
> Perhaps it can even acccept "sigset_t *newmask" and do
> set_current_blocked().
So, Al, what do you think if we do something like
--- x/arch/x86/include/asm/thread_info.h
+++ x/arch/x86/include/asm/thread_info.h
@@ -247,7 +247,6 @@ static inline void set_restore_sigmask(v
{
struct thread_info *ti = current_thread_info();
ti->status |= TS_RESTORE_SIGMASK;
- WARN_ON(!test_bit(TIF_SIGPENDING, (unsigned long *)&ti->flags));
}
static inline void clear_restore_sigmask(void)
{
--- x/include/linux/signal.h
+++ x/include/linux/signal.h
@@ -249,6 +249,13 @@ extern void __set_current_blocked(const
extern int show_unhandled_signals;
extern int sigsuspend(sigset_t *);
+static inline set_restore_xxx(sigset_t *mask)
+{
+ set_restore_sigmask();
+ current->saved_sigmask = current->blocked;
+ set_current_blocked(mask);
+}
+
struct sigaction {
#ifndef __ARCH_HAS_IRIX_SIGACTION
__sighandler_t sa_handler;
Then sys_epoll_pwait() (and other users) can simply do
SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *,
events,
int, maxevents, int, timeout, const sigset_t __user *,
sigmask,
size_t, sigsetsize)
{
int error;
/*
* If the caller wants a certain signal mask to be set during
the wait,
* we apply it here.
*/
if (sigmask) {
sigset_t ksigmask;
if (sigsetsize != sizeof(sigset_t))
return -EINVAL;
if (copy_from_user(&ksigmask, sigmask,
sizeof(ksigmask)))
return -EFAULT;
set_restore_xxx(&ksigmask);
}
error = sys_epoll_wait(epfd, events, maxevents, timeout);
if (error != -EINTR)
restore_saved_sigmask();
return error;
}
Hmm... and when I re-read your original email I am starting to think
that perhaps you proposed exactly this...
But I still think it would be better to do this change on top of the
cleanups I sent (fs/compat.c and fs/select.c should be updated too).
But, perhaps, it also makes sense to add
void restore_saved_sigmask_if(bool cond)
{
if (cond)
restore_saved_sigmask();
else
WARN_ON(TS_RESTORE_SIGMASK && !TIF_SIGPENDING);
}
so that epoll_pwait() could do
restore_saved_sigmask_if(error != -EINTR);
What do you think?
Oleg.
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