There's a reproducible kernel bug in 3.2.23-rpi1+ -- whenever cricket (http://cricket.sourceforge.net/) tries to create an RRD file, this occurs; it does not happen on other file creations...
[ 589.838325] BUG: sleeping function called from invalid context at kernel/mute
x.c:85
[ 589.838355] in_atomic(): 1, irqs_disabled(): 0, pid: 2330, name: collector
[ 589.838439] [<c0012100>] (unwind_backtrace+0x0/0xe0) from [<c032c240>] (mutex
_lock+0x18/0x40)
[ 589.838486] [<c032c240>] (mutex_lock+0x18/0x40) from [<c0090714>] (generic_fi
le_aio_write+0x44/0xc8)
[ 589.838539] [<c0090714>] (generic_file_aio_write+0x44/0xc8) from [<c0128dfc>]
(ext4_file_write+0x230/0x294)
[ 589.838594] [<c0128dfc>] (ext4_file_write+0x230/0x294) from [<c00c5e74>] (do_
sync_write+0x9c/0xd8)
[ 589.838641] [<c00c5e74>] (do_sync_write+0x9c/0xd8) from [<c00c6728>] (vfs_wri
te+0xa8/0x180)
[ 589.838671] [<c00c6728>] (vfs_write+0xa8/0x180) from [<c00c6a18>] (sys_write+
0x34/0x68)
[ 589.838709] [<c00c6a18>] (sys_write+0x34/0x68) from [<c000d580>] (ret_fast_sy
scall+0x0/0x30)
[ 589.838824] ------------[ cut here ]------------
[ 589.846909] kernel BUG at mm/filemap.c:2047!
[ 589.854554] Internal error: Oops - undefined instruction: 0 [#1]
[ 589.863946] Modules linked in: tun nls_utf8 nls_cp437 vfat fat spidev smsc95x
x usbnet leds_gpio spi_bcm2708 i2c_bcm2708
[ 589.881948] CPU: 0 Not tainted (3.2.23-rpi1+ #3)
[ 589.890476] PC is at iov_iter_copy_from_user_atomic+0x24/0xb4
[ 589.899789] LR is at 0x0
[ 589.905814] pc : [<c008e878>] lr : [<00000000>] psr: 40000013
[ 589.905826] sp : cdb41d38 ip : cdb41d78 fp : 00000000
[ 589.924437] r10: 00000000 r9 : cdb40000 r8 : 00001000
[ 589.933187] r7 : cdb40000 r6 : ce652ea0 r5 : 00000000 r4 : 00001000
[ 589.943248] r3 : 00001000 r2 : 00000000 r1 : cdb40000 r0 : c0687a20
[ 589.953231] Flags: nZcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
[ 589.963801] Control: 00c5387d Table: 0e948008 DAC: 00000015
[ 589.973045] Process collector (pid: 2330, stack limit = 0xcdb40268)
[ 589.982858] Stack: (0xcdb41d38 to 0xcdb42000)
[ 589.990740] 1d20: 00001000 00000000
[ 590.005879] 1d40: 00000000 c008ea28 00001000 00000000 cdb41d70 cdb41d74 00000000 cdb13e40
[ 590.021207] 1d60: c0344410 00001000 00000000 00000000 c0687a20 00000000 cdb41ec0 00000001
[ 590.036709] 1d80: 00000000 00001000 ce652de0 00000000 00000000 ce652de0 ce652e44 00000000
[ 590.052632] 1da0: cdb13e40 cdb13e40 00001000 c0090660 00000000 00000000 cdb41f00 00001000
[ 590.068918] 1dc0: 00000000 c000d580 00000000 cdb41ec8 cdb41ec0 cdb41f00 ce652ea0 00000001
[ 590.085584] 1de0: 00001000 ce652e44 cdb41ec8 00000001 cdb13e40 c00121b4 be8b38d4 00000000
[ 590.102480] 1e00: 00000000 00000000 ce652e44 cdb41ec8 00000001 cdb13e40 cdb41ec0 c0090730
[ 590.119572] 1e20: 00000001 00000000 91827364 cdb41e2c cdb41e2c cdb41e34 cdb41e34 00000000
[ 590.136744] 1e40: 00000000 00000000 00000000 00000000 cdb13e40 ce652de0 cdb41ec8 cdb41ec0
[ 590.154185] 1e60: 00000001 c0128dfc 00000000 00000000 cdb41ef8 cdb13e40 00000042 c00d3230
[ 590.171889] 1e80: ce64e5d8 cdad1b40 c050d5c0 2cdd052d 00000008 fffffdee 00000000 cdb41f88
[ 590.189984] 1ea0: cdb13e40 00001000 cdb40000 00000000 be8b38d4 c00c5e74 00000
[ 590.189984] 1ea0: cdb13e40 00001000 cdb40000 00000000 be8b38d4 c00c5e74 00000000 00000000
[ 590.208384] 1ec0: be8b2818 00001000 ce80e1c0 ce623238 00000000 00000001 ffffffff cdb13e40
[ 590.226938] 1ee0: 00000000 00000000 00000000 00000000 cdb02c00 00003be0 00000000 00000000
[ 590.245733] 1f00: 00000000 00000000 00000000 00000000 00001000 ce64f330 00001000 00000000
[ 590.264786] 1f20: 00000000 00000001 00000000 7ff80000 00000001 cdb13e40 cdb41f88 00001000
[ 590.283864] 1f40: cdb13e40 be8b2818 cdb41f88 cdb13e40 be8b2818 cdb41f88 be8b2818 c00c6728
[ 590.302927] 1f60: cdb13e40 be8b2818 00000000 00000000 cdb13e40 be8b2818 00001000 c00c6a18
[ 590.321992] 1f80: 00000004 00000000 00000000 00000000 01796e78 01763838 015defec 00000004
[ 590.341069] 1fa0: c000d704 c000d580 01796e78 01763838 00000004 be8b2818 00001000 be8b2818
[ 590.360124] 1fc0: 01796e78 01763838 015defec 00000004 00000003 00000000 00000001 be8b38d4
[ 590.379187] 1fe0: 402ae000 be8b2800 404a7c14 4036b54c 60000010 00000004 00000000 00000000
[ 590.398279] [<c008e878>] (iov_iter_copy_from_user_atomic+0x24/0xb4) from [<c008ea28>] (generic_file_buffered_write+0x120/0x264)
[ 590.420789] [<c008ea28>] (generic_file_buffered_write+0x120/0x264) from [<c0090660>] (__generic_file_aio_write+0x358/0x3c8)
[ 590.442962] [<c0090660>] (__generic_file_aio_write+0x358/0x3c8) from [<c0090730>] (generic_file_aio_write+0x60/0xc8)
[ 590.464513] [<c0090730>] (generic_file_aio_write+0x60/0xc8) from [<c0128dfc>] (ext4_file_write+0x230/0x294)
[ 590.485288] [<c0128dfc>] (ext4_file_write+0x230/0x294) from [<c00c5e74>] (do_sync_write+0x9c/0xd8)
[ 590.505262] [<c00c5e74>] (do_sync_write+0x9c/0xd8) from [<c00c6728>] (vfs_write+0xa8/0x180)
[ 590.524586] [<c00c6728>] (vfs_write+0xa8/0x180) from [<c00c6a18>] (sys_write+0x34/0x68)
[ 590.538200] [<c00c6a18>] (sys_write+0x34/0x68) from [<c000d580>] (ret_fast_syscall+0x0/0x30)
[ 590.557486] Code: e1a04003 e591e004 e3de5101 1a000000 (e7f001f2)
[ 590.569294] ---[ end trace a5ea58d4db817366 ]---
There's a reproducible kernel bug in 3.2.23-rpi1+ -- whenever cricket (http://cricket.sourceforge.net/) tries to create an RRD file, this occurs; it does not happen on other file creations...