[E1000-devel] igb dma bug.

[Dave J. <da...@re...>]

Fedora rawhide kernels have been carrying a set of DMA debugging patches
from dwmw2 for a while.  I just booted up a box which contains two of these..

01:00.0 Ethernet controller: Intel Corporation 82575EB Gigabit Network Connection (rev 02)
01:00.1 Ethernet controller: Intel Corporation 82575EB Gigabit Network Connection (rev 02)

And got the following trace in dmesg..

[   33.553105] ------------[ cut here ]------------
[   33.553109] WARNING: at lib/dma-debug.c:461 check_unmap+0xd4/0x3dd() (Not tainted)
[   33.553112] Hardware name: X8DTN
[   33.553115] igb 0000:01:00.0: DMA-API: device driver tries to free DMA memory it has not allocated [device address=0x00000004b6c61130] [size=342 bytes]
[   33.553119] Modules linked in: sunrpc cpufreq_ondemand acpi_cpufreq freq_table snd_seq_dummy snd_seq_oss snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss igb snd_mixer_oss snd_pcm snd_timer shpchp snd iTCO_wdt soundcore dca iTCO_vendor_support snd_page_alloc serio_raw pata_jmicron i2c_i801 irda pcspkr crc_ccitt ata_generic pata_acpi radeon drm i2c_algo_bit i2c_core [last unloaded: microcode]
[   33.553159] Pid: 3435, comm: rsyslogd Not tainted 2.6.29-0.218.rc7.git2.fc11.x86_64 #1
[   33.553162] Call Trace:
[   33.553164]  <IRQ>  [<ffffffff8104baa3>] warn_slowpath+0xbc/0xf0
[   33.553176]  [<ffffffff813967f8>] ? _spin_lock_irqsave+0x7d/0x8b
[   33.553181]  [<ffffffff811a6865>] ? get_hash_bucket+0x28/0x34
[   33.553185]  [<ffffffff811a520d>] ? swiotlb_virt_to_bus+0x1f/0x23
[   33.553190]  [<ffffffff811a6f30>] check_unmap+0xd4/0x3dd
[   33.553196]  [<ffffffff8106f5d7>] ? mark_lock+0x28/0x37f
[   33.553200]  [<ffffffff811a7386>] debug_dma_unmap_page+0x50/0x52
[   33.553211]  [<ffffffffa01753d6>] pci_unmap_page+0x4e/0x57 [igb]
[   33.553219]  [<ffffffffa017540e>] igb_unmap_and_free_tx_resource+0x2f/0x58 [igb]
[   33.553227]  [<ffffffffa0175540>] igb_clean_tx_irq+0xbf/0x32b [igb]
[   33.553231]  [<ffffffff8106fbb9>] ? trace_hardirqs_on+0xd/0xf
[   33.553238]  [<ffffffff8101781b>] ? native_sched_clock+0x2d/0x5a
[   33.553246]  [<ffffffffa01757e7>] igb_msix_tx+0x3b/0x66 [igb]
[   33.553252]  [<ffffffff81098723>] handle_IRQ_event+0x27/0x63
[   33.553256]  [<ffffffff8109a051>] handle_edge_irq+0xe0/0x129
[   33.553261]  [<ffffffff81013c04>] do_IRQ+0xd9/0x151
[   33.553265]  [<ffffffff81011e93>] ret_from_intr+0x0/0x2e
[   33.553267]  <EOI> <4>---[ end trace 642821cb9679d140 ]---
[   33.560735] dhclient[3855]: segfault at 49b82b94 ip 00000000004279a0 sp 00007fffac150b80 error 4 in dhclient[400000+7f000]

Is this a useful trace ?

>From a quick eyeball of the code, I'm not entirely sure what goes on here,
so figured I'd share it before I dive deeper.

	Dave

-- 
http://www.codemonkey.org.uk