Re: [patches] kernel timer races

From: bug1 (
Date: Thu May 25 2000 - 10:10:52 EST

> There's also a bit of temp diagnostic/debuggy stuff in this patch.
> - Detect the occurence of CPU0 doing a del_timer() during
> CPU1's execution of the handler. If this does occur, direct
> people to
> Reminder: this scenario is the whole reason for this
> patch (and this long email). We need to gather these statistics
> so we can decide whether or not to patch 2.2. If I don't get
> any emails this whole thing was a waste of time. (But I've
> already seen it happen three times, and I haven't even tried...)

Hi, i just got your "del_timer(c77ebf40) during handler execution"

I got the message seconds prior to a "hdk: timeout waiting for DMA"

Ive been having DMA problems for a long time with my HPT366
controller(s) which is why i tried your patch. hdk is my onboard hpt366
controller, i have a bp6 dual celeron with a promise ultra66 card to
give 6 ide channels. (more details if interested)

The program i was running that caused the DMA timeout was,
which is a disk benchmark script that uses tiotest.

Im using 2.3.99-pre10-pre3 + your timer-race-6 patch, i did "tweak" the
kernel a bit to force my HPT366 to not use UDMA66, by changing #define
HPT366_ALLOW_ATA66_3 (and 4) to 0.
Prior to this tweak the kernel locked up after testing with bonnie.

So, this means that a race condition was found. Is it likely that this
race condition was casued by the DMA timeout, or could the DMA timeout
be caused by the race ?



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