Re: [linux-usb-devel] 2.6.20 kernel hang with USB drive and vfat doing ftruncate

From: Kumar Gala
Date: Thu Feb 22 2007 - 02:41:56 EST



On Feb 21, 2007, at 3:31 PM, Andrew Morton wrote:

On Wed, 21 Feb 2007 16:22:17 -0500 (EST)
Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:

On Wed, 21 Feb 2007, Andrew Morton wrote:

It seems like usb-storage and aio are completely off in the weeds.
Ideas?

It seems usb-storage should remove some kmalloc and use mempool () for
urb... Is someone working on this? And idea?

I think Pete said that we're supposed to be using GFP_NOIO in there.

We _are_ using it.

How admirably prompt.

Not that it'll help much: the VM calls throttle_vm_writeout() for GFP_NOIO
and GFP_NOFS allocations, which is a bug. Because if the caller holds
locks which prevent filesystem or IO progress, we deadlock.

I'll fix the VM if someone else fixes USB ;)

What else needs to be fixed?

Would be nice if someone can confirm that this fixes it:

Doesn't seem to help my problem in a quick test, will get more data in the morning.

- k
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