Hi,
I think I'm hitting a rare bug in rt2x00lib_txdone(). Usually I can't
capture it since a second or third bug hits immediately after and
everything wraps off the screen. I'm fairly certain the same bug is
hitting on rc8, but I only got the oops in my logs with an rc7 kernel
including the latest net tree merge. Reproducing the bug is hit or miss
and I don't know a good way to trigger it.
I have an rt73usb device on an x86_64 machine, lsusb shows:
Bus 001 Device 004: ID 050d:705a Belkin Components F5D7050 Wireless G
Adapter v3000 [Ralink RT2573]
This is all of the oops that I could recover.
[ 9085.714105] BUG: unable to handle kernel NULL pointer dereference at
00000000000000a4
[ 9085.714816] IP: [<ffffffffa0025458>] rt2x00lib_txdone+0x36/0x249
[rt2x00lib]
[ 9085.715017] PGD 215fd067 PUD 292f4067 PMD 0
[ 9085.715017] Oops: 0000 [#1] SMP
[ 9085.715017] last sysfs file:
/sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq
[ 9085.715017] CPU 1
[ 9085.715017] Modules linked in: usb_storage thermal snd_seq_oss
snd_seq_midi snd_seq_dummy snd_pcm_oss snd_mixer_oss snd_hrtimer
snd_emu10k1_synth snd_emux_synth snd_seq_virmidi snd_seq_midi_event
snd_seq_midi_emul snd_seq scsi_wait_scan powernow_k8 mperf i2c_i801 fuse
fan snd_emu10k1 snd_rawmidi snd_ac97_codec ac97_bus snd_pcm
snd_seq_device snd_timer snd_page_alloc snd_util_mem rt73usb crc_itu_t
rt2x00usb snd_hwdep snd processor r8169 via82cxxx rt2x00lib soundcore
mii button k8temp
[ 9085.715017]
[ 9085.715017] Pid: 11513, comm: kworker/1:0 Not tainted 2.6.37-rc7+ #27
MS-7094/MS-7094
[ 9085.715017] RIP: 0010:[<ffffffffa0025458>] [<ffffffffa0025458>]
rt2x00lib_txdone+0x36/0x249 [rt2x00lib]
[ 9085.715017] RSP: 0000:ffff880000057ca0 EFLAGS: 00010286
[ 9085.715017] RAX: 0000000000000030 RBX: ffff88003b64e3c0 RCX:
ffff880000057ca0
[ 9085.715017] RDX: 0000000000000006 RSI: ffff880000057d00 RDI:
0000000000000000
[ 9085.715017] RBP: ffff880000057cf0 R08: ffff88003c7c7110 R09:
0000000000000001
[ 9085.715017] R10: ffffffff81df3c10 R11: 0000000000000282 R12:
ffff88003c586280
[ 9085.715017] R13: 0000000000000000 R14: 0000000000000028 R15:
ffff880000057d00
[ 9085.715017] FS: 00002b41e037b160(0000) GS:ffff88003f
I think the entry or skb in the entry is NULL, but I'm not sure how
that's possible. Here's an objdump of the erroring code if that helps.
0000000000000422 <rt2x00lib_txdone>:
422: 55 push %rbp
423: 48 89 e5 mov %rsp,%rbp
426: 41 57 push %r15
428: 41 56 push %r14
42a: 41 55 push %r13
42c: 41 54 push %r12
42e: 53 push %rbx
42f: 48 83 ec 28 sub $0x28,%rsp
433: e8 00 00 00 00 callq 438 <rt2x00lib_txdone+0x16>
438: 4c 8b 6f 10 mov 0x10(%rdi),%r13
43c: 48 8b 47 08 mov 0x8(%rdi),%rax
440: 49 89 fc mov %rdi,%r12
443: 49 89 f7 mov %rsi,%r15
446: 48 8b 18 mov (%rax),%rbx
449: 49 8d 45 30 lea 0x30(%r13),%rax
44d: 4c 89 ef mov %r13,%rdi
450: 4d 8d 75 28 lea 0x28(%r13),%r14
454: 48 89 45 c8 mov %rax,-0x38(%rbp)
458: 41 8b 95 a4 00 00 00 mov 0xa4(%r13),%edx <--- here
45f: 66 89 55 c2 mov %dx,-0x3e(%rbp)
463: e8 00 00 00 00 callq 468 <rt2x00lib_txdone+0x46>
468: 89 45 c4 mov %eax,-0x3c(%rbp)
46b: 41 8a 45 30 mov 0x30(%r13),%al