Fix timeouts in sys_pselect7

commit 62568510b8e2679cbc331d7de10ea9ba81ae8b3d upstream.

Since we (Analog Devices) updated our Blackfin kernel to 2.6.28, we've
seen occasional 5-second hangs from telnet.  telnetd calls select with a
NULL timeout, but with the new kernel, the system call occasionally
returns 0, which causes telnet to call sleep (5).  This did not happen
with earlier kernels.

The code in sys_pselect7 looks a bit strange, in particular the variable
"to" is initialized to NULL, then changed if a non-null timeout was
passed in, but not used further.  It needs to be passed to
core_sys_select instead of &end_time.

This bug was introduced by 8ff3e8e85fa6c312051134b3953e397feb639f51
("select: switch select() and poll() over to hrtimers").

Signed-off-by: Bernd Schmidt <bernd.schmidt@analog.com>
Reviewed-by: Ulrich Drepper <drepper@redhat.com>
Tested-by: Robin Getz <rgetz@blackfin.uclinux.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/fs/select.c b/fs/select.c
index 3da402681dd258ab1d031821566ac15d56fa6705..b140f906afd324c33f11d0fba72353a5c22b2dfc 100644 (file)
--- a/fs/select.c
+++ b/fs/select.c
@@ -560,7 +560,7 @@ static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp,
                sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
        }
 
-       ret = core_sys_select(n, inp, outp, exp, &end_time);
+       ret = core_sys_select(n, inp, outp, exp, to);
        ret = poll_select_copy_remaining(&end_time, tsp, 0, ret);
 
        if (ret == -ERESTARTNOHAND) {