[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Bug#404815: marked as done (linux-image-2.6.18-3-686: Problems opening serial ports.)

Your message dated Sun, 29 Jul 2007 11:13:00 +0200
with message-id <20070729091300.GA4795@stro.at>
and subject line linux-image-2.6.18-3-686: Problems opening serial ports.
has caused the attached Bug report to be marked as done.

This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.

(NB: If you are a system administrator and have no idea what I am
talking about this indicates a serious mail system misconfiguration
somewhere.  Please contact me immediately.)

Debian bug tracking system administrator
(administrator, Debian Bugs database)
--- Begin Message --- 
Package: linux-image-2.6.18-3-686
Version: 2.6.18-7
Severity: normal

It seems that the kernel has some races in opening/closing of serial
ports. Simple C program below just opens/closes a port in a loop.
When I run the program, I begin to get the following in dmesg even
though the port is not connected (idle):

irq 4: nobody cared (try booting with the "irqpoll" option)
 [<c014037f>] __report_bad_irq+0x2b/0x69
 [<c014056c>] note_interrupt+0x1af/0x1e7
 [<c013fb83>] handle_IRQ_event+0x23/0x49
 [<c013fc5c>] __do_IRQ+0xb3/0xe8
 [<c01050e5>] do_IRQ+0x43/0x52
 [<c01036b6>] common_interrupt+0x1a/0x20
 [<c0101b91>] mwait_idle+0x25/0x38
 [<c0101b52>] cpu_idle+0x9f/0xb9
 [<c03186fd>] start_kernel+0x379/0x380
handlers:
[<c020e07b>] (serial8250_interrupt+0x0/0xdd)
Disabling IRQ #4

In addition, when two copies of this program are run simultaneously on
my hyper-thread Pentium 4 box, each of copies start to randomly fail to
open the port with errno=5 (Input/output error).

Note that I've tested this both with standard PC port ttyS0 and with
serial ports of MOXA multi-port serial board (ttyM*), and [mis]behavior
is the same. Also note that opening /dev/null instead of serial port
doesn't have the problem.

Here is the C program:

#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>

int main()
{
  while(1) {
    int fd = open("/dev/ttyS0", O_RDONLY | O_NOCTTY);
    if(fd < 0)
      fprintf(stderr, "%s\n", strerror(errno));
    else
      close(fd);
  }
}

-- System Information:
Debian Release: testing/unstable
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: i386 (i686)
Shell:  /bin/sh linked to /bin/bash
Kernel: Linux 2.6.18-3-686
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)

Versions of packages linux-image-2.6.18-3-686 depends on:
ii  coreutils                     5.96-5     The GNU core utilities
ii  debconf [debconf-2.0]         1.5.3      Debian configuration management sy
ii  initramfs-tools [linux-initra 0.77b      tools for generating an initramfs
ii  module-init-tools             3.2.2-3    tools for managing Linux kernel mo

Versions of packages linux-image-2.6.18-3-686 recommends:
ii  libc6-i686                   2.3.6.ds1-4 GNU C Library: Shared libraries [i

-- debconf information:
  linux-image-2.6.18-3-686/postinst/bootloader-error-2.6.18-3-686:
  linux-image-2.6.18-3-686/postinst/old-dir-initrd-link-2.6.18-3-686: true
  linux-image-2.6.18-3-686/postinst/kimage-is-a-directory:
  linux-image-2.6.18-3-686/postinst/old-system-map-link-2.6.18-3-686: true
  linux-image-2.6.18-3-686/postinst/create-kimage-link-2.6.18-3-686: true
  linux-image-2.6.18-3-686/postinst/bootloader-test-error-2.6.18-3-686:
  linux-image-2.6.18-3-686/preinst/abort-overwrite-2.6.18-3-686:
  linux-image-2.6.18-3-686/postinst/old-initrd-link-2.6.18-3-686: true
  shared/kernel-image/really-run-bootloader: true
  linux-image-2.6.18-3-686/preinst/elilo-initrd-2.6.18-3-686: true
  linux-image-2.6.18-3-686/preinst/lilo-initrd-2.6.18-3-686: true
  linux-image-2.6.18-3-686/postinst/depmod-error-initrd-2.6.18-3-686: false
  linux-image-2.6.18-3-686/preinst/bootloader-initrd-2.6.18-3-686: true
  linux-image-2.6.18-3-686/prerm/removing-running-kernel-2.6.18-3-686: true
  linux-image-2.6.18-3-686/prerm/would-invalidate-boot-loader-2.6.18-3-686: true
  linux-image-2.6.18-3-686/preinst/abort-install-2.6.18-3-686:
  linux-image-2.6.18-3-686/preinst/overwriting-modules-2.6.18-3-686: true
  linux-image-2.6.18-3-686/preinst/initrd-2.6.18-3-686:
  linux-image-2.6.18-3-686/preinst/lilo-has-ramdisk:
  linux-image-2.6.18-3-686/preinst/already-running-this-2.6.18-3-686:
  linux-image-2.6.18-3-686/postinst/depmod-error-2.6.18-3-686: false
  linux-image-2.6.18-3-686/preinst/failed-to-move-modules-2.6.18-3-686:

--- End Message ---
--- Begin Message --- 
Version: 2.6.22-1

thanks to dannf for verifying that the bug is closed in between,
see upstream report
http://bugzilla.kernel.org/show_bug.cgi?id=7750

as "funny" side remark that bug only appeared on !preemption,
now that almost any distro is switching to preemption it
might be the time to start thinking to do so too.

closing

-- 
maks

--- End Message ---
Reply to: