Re: [BUG] 2.6.24-rc5: 'sysctl table check failed' when turning on printer

Frans Pop <elendil@xxxxxxxxx> writes:

On Sunday 06 January 2008, Eric W. Biederman wrote:
Short of two programs coming in and simultaneously trying to claim
the parallel port and there being not exclusion in ppdev.c I don't
have a clue what could cause the reported error.

That could well be the root cause as the full log shows:

Ok. Looking at it there is mutual exclusion for the parallel port
after we register.

So my guess is:

Two programs open the parellel port device.
The open goes through ppdev.c
ppdev.c uses the same name for both.
parport doesn't do any mutual exclusion (except for claim).
Everything except sysctl happens inside of the claim so we
haven't seen any other bugs.

So if my guess is right we need to move the register_sysctl_table
call into the claim logic. And the unregister_syctl_table
call into the unclaim logic.

I've got to run.

Later,
Eric



Jan 6 01:21:02 faramir kernel: ppdev0: registered pardevice
Jan 6 01:21:03 faramir kernel: sysctl table check failed:
/dev/parport/parport0/devices/ppdev0/timeslice Sysctl already exists
Jan 6 01:21:03 faramir kernel: Pid: 11078, comm: hpijs Not tainted 2.6.24-rc6 #1
Jan 6 01:21:03 faramir kernel:
Jan 6 01:21:03 faramir kernel: Call Trace:
Jan 6 01:21:03 faramir kernel: [<ffffffff8024c104>] set_fail+0x3f/0x47
Jan 6 01:21:03 faramir kernel: [<ffffffff8024c5ba>]
sysctl_check_table+0x4ae/0x4fb
Jan 6 01:21:03 faramir kernel: [<ffffffff8024c0b6>]
sysctl_check_lookup+0xc1/0xd0
Jan 6 01:21:03 faramir kernel: [<ffffffff8024c5d0>]
sysctl_check_table+0x4c4/0x4fb
Jan 6 01:21:03 faramir kernel: [<ffffffff8024c0b6>]
sysctl_check_lookup+0xc1/0xd0
Jan 6 01:21:03 faramir kernel: [<ffffffff8024c5d0>]
sysctl_check_table+0x4c4/0x4fb
Jan 6 01:21:03 faramir kernel: [<ffffffff8024c0b6>]
sysctl_check_lookup+0xc1/0xd0
Jan 6 01:21:03 faramir kernel: [<ffffffff8024c5d0>]
sysctl_check_table+0x4c4/0x4fb
Jan 6 01:21:03 faramir kernel: [<ffffffff8024c0b6>]
sysctl_check_lookup+0xc1/0xd0
Jan 6 01:21:03 faramir kernel: [<ffffffff8024c5d0>]
sysctl_check_table+0x4c4/0x4fb
Jan 6 01:21:03 faramir kernel: [<ffffffff8024c0b6>]
sysctl_check_lookup+0xc1/0xd0
Jan 6 01:21:03 faramir kernel: [<ffffffff8024c5d0>]
sysctl_check_table+0x4c4/0x4fb
Jan 6 01:21:03 faramir kernel: [<ffffffff8023ca8d>]
register_sysctl_table+0x52/0x9d
Jan 6 01:21:03 faramir kernel: [<ffffffff881ea7cb>]
:parport:parport_device_proc_register+0xc3/0xe3
Jan 6 01:21:03 faramir kernel: [<ffffffff881e8da7>]
:parport:parport_register_device+0x206/0x267
Jan 6 01:21:03 faramir kernel: [<ffffffff884151ae>] :ppdev:pp_irq+0x0/0x40
Jan 6 01:21:03 faramir kernel: [<ffffffff8841574f>] :ppdev:pp_ioctl+0x13f/0x77c
Jan 6 01:21:03 faramir kernel: [<ffffffff80296a55>] do_ioctl+0x55/0x6b
Jan 6 01:21:03 faramir kernel: [<ffffffff80296cae>] vfs_ioctl+0x243/0x25c
Jan 6 01:21:03 faramir kernel: [<ffffffff80296d18>] sys_ioctl+0x51/0x71
Jan 6 01:21:03 faramir kernel: [<ffffffff8020beee>] system_call+0x7e/0x83
Jan 6 01:21:03 faramir kernel:
Jan 6 01:21:03 faramir kernel: ppdev0: registered pardevice
Jan 6 01:22:10 faramir kernel: ppdev0: released pardevice because user-space
forgot
Jan 6 01:22:10 faramir kernel: ppdev0: unregistered pardevice
Jan 6 01:22:11 faramir kernel: ppdev0: unregistered pardevice
Jan 6 03:24:57 faramir kernel: fuse exit

Sorry for not providing that info earlier, but the first time I had this
issue I had two print jobs after eachother and because of that I overlooked
the double registering.

I am printing through CUPS on a fairly standard Debian unstable system
running the KDE desktop.
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