Re: [Bisected] commit 71574865 (vfs: do_last(): common slow lookup)breaks CUPS printing

From: Markus Trippelsdorf
Date: Mon Jul 30 2012 - 04:05:36 EST


On 2012.07.30 at 08:56 +0100, Al Viro wrote:
> On Mon, Jul 30, 2012 at 09:10:23AM +0200, Markus Trippelsdorf wrote:
> >
> > Looks like you're right. The first warning happens during startup. The last one
> > when I print a test page (which now succeeds).
> > Thanks Al.
>
> > WTF: open("/dev/input/mice", 34946)
> > WTF: open("/dev/usblp0", 32898)
> > WTF: open("/dev/usb/lp0", 32898)
>
> Ahhh... OK, yes - it's the case we had missed (and where the manpage
> needs correction, BTW). O_EXCL for *devices* has additional semantics;
> it's not "fail if exists", it's "fail if already opened by somebody".
> No need to pester CUPS folks (except that I really hope that this
> open of /dev/input/mice does *not* come from them)...

I've omitted some WTF's from my former reply, because they happend after
I've sent it.

Jul 30 09:06:51 x4 kernel: ------------[ cut here ]------------
Jul 30 09:06:51 x4 kernel: WARNING: at fs/open.c:899 do_sys_open+0x1e5/0x220()
Jul 30 09:06:51 x4 kernel: Hardware name: System Product Name
Jul 30 09:06:51 x4 kernel: Pid: 87, comm: cupsd Tainted: G W 3.5.0-07078-gf7da9cd-dirty #199
Jul 30 09:06:51 x4 kernel: Call Trace:
Jul 30 09:06:51 x4 kernel: WTF: open("/dev/usb/lp0", 32898)
Jul 30 09:06:51 x4 kernel: [<ffffffff810555a4>] ? warn_slowpath_common+0x74/0xb0
Jul 30 09:06:51 x4 kernel: [<ffffffff810dd405>] ? do_sys_open+0x1e5/0x220
Jul 30 09:06:51 x4 kernel: [<ffffffff814a64a2>] ? system_call_fastpath+0x16/0x1b
Jul 30 09:06:51 x4 kernel: ---[ end trace 9a333bfb6a9cbe83 ]---
Jul 30 09:07:19 x4 kernel: WTF: open("/var/spool/cups/a00018", 32897)
Jul 30 09:07:19 x4 kernel: ------------[ cut here ]------------
Jul 30 09:07:19 x4 kernel: WARNING: at fs/open.c:899 do_sys_open+0x1e5/0x220()
Jul 30 09:07:19 x4 kernel: Hardware name: System Product Name
Jul 30 09:07:19 x4 kernel: Pid: 87, comm: cupsd Tainted: G W 3.5.0-07078-gf7da9cd-dirty #199
Jul 30 09:07:19 x4 kernel: Call Trace:
Jul 30 09:07:19 x4 kernel: [<ffffffff810555a4>] ? warn_slowpath_common+0x74/0xb0
Jul 30 09:07:19 x4 kernel: [<ffffffff810dd405>] ? do_sys_open+0x1e5/0x220
Jul 30 09:07:19 x4 kernel: [<ffffffff814a64a2>] ? system_call_fastpath+0x16/0x1b
Jul 30 09:07:19 x4 kernel: ---[ end trace 9a333bfb6a9cbe84 ]---
Jul 30 09:30:40 x4 kernel: WTF: open("/var/cache/cups/job.cache.O", 32897)
Jul 30 09:30:40 x4 kernel: ------------[ cut here ]------------
Jul 30 09:30:40 x4 kernel: WARNING: at fs/open.c:899 do_sys_open+0x1e5/0x220()
Jul 30 09:30:40 x4 kernel: Hardware name: System Product Name
Jul 30 09:30:40 x4 kernel: Pid: 87, comm: cupsd Tainted: G W 3.5.0-07078-gf7da9cd-dirty #199
Jul 30 09:30:40 x4 kernel: Call Trace:
Jul 30 09:30:40 x4 kernel: [<ffffffff810555a4>] ? warn_slowpath_common+0x74/0xb0
Jul 30 09:30:40 x4 kernel: [<ffffffff810dd405>] ? do_sys_open+0x1e5/0x220
Jul 30 09:30:40 x4 kernel: [<ffffffff814a64a2>] ? system_call_fastpath+0x16/0x1b
Jul 30 09:30:40 x4 kernel: ---[ end trace 9a333bfb6a9cbe85 ]---

/var/spool/cups/a00018 & /var/cache/cups/job.cache.O are not devices AFAICS.

--
Markus
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