Home » Mailing list archives » linux-kernel » 2010 » August » 4

Re: [PATCH 1/3] Input: sysrq - drop tty argument from sysrq ops handlers

Previous message: [thread] [date] [author]
Next message: [thread] [date] [author]
[view in full thread]
From: Benjamin Herrenschmidt
Subject: Re: [PATCH 1/3] Input: sysrq - drop tty argument from sysrq ops handlers
Date: Wednesday, August 4, 2010 - 1:33 am

On Wed, 2010-08-04 at 00:59 -0700, Dmitry Torokhov wrote:

While talking about sysrq...

I noticed that serial drivers call sysrq with the uart lock held.

I've seen deadlocks caused by that, for example, when entering the
debugger, it waits forever for a CPU which is itself waiting on the UART
lock.

I have a patch to drop the lock in serial_core.h, I'll post that
tomorrow hopefully, just checking if there's any objection there ? The
serial drivers might need to be audited a bit to make sure they cope
with the lock being dropped and re-acquired around the sysrq call.

Cheers,
Ben.
 

--
Previous message: [thread] [date] [author]
Next message: [thread] [date] [author]
Messages in current thread:
[PATCH 0/3] SysRq: do not pass tty argument around, Dmitry Torokhov, (Wed Aug 4, 12:58 am)
[PATCH 1/3] Input: sysrq - drop tty argument from sysrq op ..., Dmitry Torokhov, (Wed Aug 4, 12:59 am)
[PATCH 2/3] Input: sysrq - drop tty argument form handle_s ..., Dmitry Torokhov, (Wed Aug 4, 12:59 am)
[PATCH 3/3] USB: drop tty argument from usb_serial_handle_ ..., Dmitry Torokhov, (Wed Aug 4, 12:59 am)
Re: [PATCH 1/3] Input: sysrq - drop tty argument from sysr ..., Benjamin Herrenschmidt, (Wed Aug 4, 1:33 am)
Re: [PATCH 1/3] Input: sysrq - drop tty argument from sysr ..., Alan Cox, (Wed Aug 4, 2:09 am)
Re: [PATCH 0/3] SysRq: do not pass tty argument around, Alan Cox, (Wed Aug 4, 2:11 am)
Re: [PATCH 2/3] Input: sysrq - drop tty argument form hand ..., Jason Wessel, (Wed Aug 4, 4:25 am)
Re: [PATCH 3/3] USB: drop tty argument from usb_serial_han ..., Jason Wessel, (Wed Aug 4, 4:25 am)
Re: [PATCH 1/3] Input: sysrq - drop tty argument from sysr ..., Jason Wessel, (Wed Aug 4, 5:03 am)
Re: [PATCH 0/3] SysRq: do not pass tty argument around, Greg KH, (Wed Aug 4, 12:44 pm)
Re: [PATCH 1/3] Input: sysrq - drop tty argument from sysr ..., Benjamin Herrenschmidt, (Wed Aug 4, 6:59 pm)
Re: [PATCH 1/3] Input: sysrq - drop tty argument from sysr ..., Benjamin Herrenschmidt, (Wed Aug 4, 7:03 pm)