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From: Bernd Schmidt <bernds_cb1@t-online.de>
To: Arjan van de Ven <arjan@linux.intel.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"Hennerich, Michael" <Michael.Hennerich@analog.com>
Subject: Fix timeouts in sys_pselect7
Date: Tue, 13 Jan 2009 18:29:56 +0100	[thread overview]
Message-ID: <496CCF94.8050304@t-online.de> (raw)

[-- Attachment #1: Type: text/plain, Size: 947 bytes --]

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.  The patch below passes it to
core_sys_select instead of &end_time, and this appears to fix the
problem.  Does this look like the correct approach?

Signed-off-by: Bernd Schmidt <bernd.schmidt@analog.com>
-- 
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[-- Attachment #2: select.diff --]
[-- Type: text/plain, Size: 530 bytes --]

 fs/select.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/select.c b/fs/select.c
index 08b91be..b0cf1f0 100644
--- a/fs/select.c
+++ b/fs/select.c
@@ -610,7 +610,7 @@ asmlinkage long sys_pselect7(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) {

             reply	other threads:[~2009-01-13 17:29 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-01-13 17:29 Bernd Schmidt [this message]
2009-01-13 19:38 ` Fix timeouts in sys_pselect7 Ulrich Drepper
2009-01-13 20:10   ` Robin Getz
  -- strict thread matches above, loose matches on Subject: below --
2009-01-13 21:14 Bernd Schmidt

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