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Date: Sat, 15 Mar 2003 16:11:28 -0500 (EST)
From: Zwane Mwaikambo <zwane@holomorphy.com>
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To: Willem Riede <wrlk@riede.org>
cc: dan carpenter <d_carpenter@sbcglobal.net>,
       Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: Any hope for ide-scsi (error handling)?
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On Sat, 15 Mar 2003, Willem Riede wrote:

> Indeed. If you get there, the command in progress is hung.
> To be able to restart the device, the old command needs to be
> aborted. But that is an inherently racy undertaking. 
> 
> Nominally, I just want to set HWGROUP(drive)->handler = NULL.
> But there is a small chance, that there is actually (interrupt) 
> activity going on for the command, which would result in a new 
> entry in HWGROUP(drive)->handler popping up after it is cleared.
> 
> The loop as programmed significantly increases the odds that 
> the old command is really aborted. 
> 
> It may not be elegant to schedule(1) with the lock taken, but it
> does work.
> 
> However, my latest patch doesn't seem to be applied, since in my
> version I have a set_current_state(TASK_INTERRUPTIBLE); before 
> the schedule.

Yeah but what happens when a task tries to acquire ide_lock? Incidentally 
this one crept in via timer softirq so if ide_timer_expiry gets there 
before your scheduled timeout timer?

NMI Watchdog detected LOCKUP on CPU0, eip c02be73d, registers:
CPU:    0
EIP:    0060:[<c02be73d>]    Tainted: PF 
EFLAGS: 00000086
EIP is at .text.lock.ide_io+0x40/0x93

Call Trace:
 [<c03557e1>] i8042_timer_func+0x21/0x30
 [<c02bdcc0>] ide_timer_expiry+0x0/0x310

-- 
function.linuxpower.ca
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