Messages in this thread Patch in this message | | | Date | Sun, 29 Jul 2007 19:05:05 +0200 | From | Manfred Spraul <> | Subject | [PATCH] Use ERESTARTNOHAND if poll() is interrupted by a signal |
| |
Hi Andrew,
poll() returns -EINTR if a signal is pending. EINTR is a bad choice: it means that poll returns to user space if the task is stopped by SIGSTOP/SIGCONT or by the freezer. select() and ppoll() both use ERESTARTNOHAND, this avoids a return to user space for signals that are handled by the kernel.
The patch switches poll() to ERESTARTNOHAND. Tested with FC6. Patch against 2.6.23-rc1-mm1.
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
--- 2.6/fs/select.c 2007-07-28 20:31:51.000000000 +0200 +++ build-2.6/fs/select.c 2007-07-28 21:21:52.000000000 +0200 @@ -621,7 +621,7 @@ static int do_poll(unsigned int nfds, s if (!count) { count = wait->error; if (signal_pending(current)) - count = -EINTR; + count = -ERESTARTNOHAND; } if (count || !*timeout) break; @@ -774,7 +774,7 @@ asmlinkage long sys_ppoll(struct pollfd ret = do_sys_poll(ufds, nfds, &timeout); /* We can restart this syscall, usually */ - if (ret == -EINTR) { + if (ret == -ERESTARTNOHAND) { /* * Don't restore the signal mask yet. Let do_signal() deliver * the signal on the way back to userspace, before the signal @@ -785,7 +785,6 @@ asmlinkage long sys_ppoll(struct pollfd sizeof(sigsaved)); set_thread_flag(TIF_RESTORE_SIGMASK); } - ret = -ERESTARTNOHAND; } else if (sigmask) sigprocmask(SIG_SETMASK, &sigsaved, NULL); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |