Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [PATCH] tty: avoid recursive BTM in pty_close | Date | Fri, 18 Jun 2010 20:35:17 +0200 |
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On Friday 18 June 2010, Tony Luck wrote: > On Fri, Jun 18, 2010 at 9:21 AM, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote: > > So I ack this patch - it's the only way to find out 8) > > Here's the results from this patch on top of next-20100618 > > The "WARNING: at include/linux/tty.h:589 tty_open+0x9d0/0xc60()" messages > are back, two of them, both with same stack trace: > > > Call Trace: > [<a0000001000159d0>] show_stack+0x50/0xa0 > [<a00000010090f270>] dump_stack+0x30/0x50 > [<a00000010008e2c0>] warn_slowpath_common+0xc0/0x120 > [<a00000010008e360>] warn_slowpath_null+0x40/0x60 > [<a00000010053eb40>] tty_open+0x160/0xc60 > [<a0000001001af9b0>] chrdev_open+0x310/0x360 > [<a0000001001a58b0>] __dentry_open+0x350/0x680 > [<a0000001001a5d80>] nameidata_to_filp+0x80/0xc0 > [<a0000001001bfee0>] finish_open+0x160/0x380 > [<a0000001001c0cc0>] do_last+0xbc0/0xce0 > [<a0000001001c5270>] do_filp_open+0x2f0/0xb40 > [<a0000001001a5290>] do_sys_open+0x90/0x200 > [<a0000001001a54d0>] sys_open+0x50/0x80 > [<a000000100b907e0>] kernel_init+0x340/0x420 > [<a000000100013c10>] kernel_thread_helper+0x30/0x60 > [<a00000010000a0c0>] start_kernel_thread+0x20/0x40
Ok, this is the same one you reported at first. I forgot to mention that the other patch I sent as a reply to your report is still needed and not yet in -next since I'm trying to sort through the other BKL removal patches now. This instance of the WARN_ON is completely harmless though, you could consider this one a false positive.
> The tty_release() ones have all gone though.
ok, good.
> I've also just noticed that the serial console output gets garbled > (like it is at the wrong baud rate) when userland code starts > printing messages. Stays garbled until /sbin/agetty starts up > to print the "Welcome ... login:" banner. > > Similar garbage when shutting down with "reboot" command. > I can see "INIT", then it all goes to pieces until I see the kernel > print "Restarting system".
Do you know if this was a problem with the original series or something that got introduced by my last patch? Also, if you don't mind, could you try if the problem also exists with CONFIG_TTY_MUTEX enabled? Which serial driver do you use?
I'll try to set up a serial console here to reproduce and bisect this problem on my own system.
Arnd
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