Your message dated Sun, 29 Jul 2007 11:13:00 +0200
with message-id <[EMAIL PROTECTED]>
and subject line linux-image-2.6.18-3-686: Problems opening serial ports.
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--- 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 ---
