Re: 2.6.20 kernel hang with USB drive and vfat doing ftruncate

From: Kumar Gala
Date: Sat Feb 17 2007 - 00:07:10 EST

On Feb 16, 2007, at 5:10 PM, Robert Hancock wrote:

Kumar Gala wrote:
I'm seeing an issue with a stock 2.6.20 kernel running on an embedded PPC. I've got a usb flash drive plugged in and the filesystem on the drive is vfat. Running with 64M and no swap.
If I execute a series of large (100M+) ftruncate() on the disk the kernel will hang and never return. It seems to be stuck in the idle loop().

On FAT filesystems this forces the entire file contents of that size to be written out with zeros. Are you sure the kernel just isn't busy writing out all that data to the disk?

I'm pretty sure, seeing as if I run the test it takes maybe 20-30 seconds to create the file if it succeeds. However, I've weighted 10 minutes and still no prompt.

I'm also able to break in with a HW debugger and am always in the idle loop.

- k
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