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

[Robert Hancock <hancockr@shaw.ca>]

Kumar Gala wrote:
> [  497.499249] usb-storage   D 00000000     0   671      5           
> 773   670 (L-TLB)
> [  497.506930] Call Trace:
> [  497.509372] [C3F35A60] [C00083AC] __switch_to+0x28/0x40
> [  497.514608] [C3F35A80] [C01F4B78] schedule+0x324/0x6bc
> [  497.519756] [C3F35AC0] [C01F5D6C] schedule_timeout+0x6c/0xd0
> [  497.525426] [C3F35B00] [C01F5C9C] io_schedule_timeout+0x30/0x54
> [  497.531356] [C3F35B20] [C0050DE4] congestion_wait+0x64/0x8c
> [  497.536941] [C3F35B70] [C004A9F0] throttle_vm_writeout+0x1c/0x84
> [  497.542958] [C3F35B90] [C004F33C] shrink_zone+0xbb0/0xfe4
> [  497.548367] [C3F35D40] [C004F8F4] try_to_free_pages+0x184/0x2cc
> [  497.554298] [C3F35DB0] [C0049AA8] __alloc_pages+0x110/0x2c0
> [  497.559878] [C3F35E00] [C0060F84] cache_alloc_refill+0x394/0x694
> [  497.565900] [C3F35E30] [C00614A0] __kmalloc+0xc4/0xcc
> [  497.570961] [C3F35E40] [C01544D0] usb_alloc_urb+0x1c/0x5c
> [  497.576371] [C3F35E50] [C015520C] usb_sg_init+0x1a0/0x2f8
> [  497.581779] [C3F35EA0] [C0167318] usb_stor_bulk_transfer_sg+0x8c/0x138
> [  497.588317] [C3F35ED0] [C0167960] usb_stor_Bulk_transport+0x140/0x310
> [  497.594767] [C3F35F00] [C0167DCC] usb_stor_invoke_transport+0x2c/0x344
> [  497.601303] [C3F35F50] [C0166B2C] 
> usb_stor_transparent_scsi_command+0x10/0x20
> [  497.608449] [C3F35F60] [C0168498] usb_stor_control_thread+0x1f8/0x290
> [  497.614900] [C3F35FC0] [C0033E48] kthread+0xf4/0x130
> [  497.619876] [C3F35FF0] [C001093C] kernel_thread+0x44/0x60

This seems like a problem, the usb-storage thread is trying to allocate 
some memory which is ending up waiting for VM writeout, which obviously 
won't proceed since this thread is the one that needs to do this.. It 
looks like the allocation in usb_stor_bulk_transfer_sglist is done with 
GFP_NOIO, so I wonder why we're getting into this state?

--
Robert Hancock      Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@nospamshaw.ca
Home Page: http://www.roberthancock.com/

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