kernel crash after enable ecryptfs under abnormal power off

[Hanks Wang <wangwenjie@cmos.net>]

Hi Tyler,

It happened kernel crash if we enable ecryptfs in kernel-space and mount 
ecryptfs in the user-space if we reboot device after the device is 
powered off abnormally, such as the device is pulled off power line. At 
the same time, if we normally power off the device and reboot it, it 
works well. I don't try this case on the computer device, it just 
happened on my own mobile device, because I want to use ecryptfs on the 
mobile area.

I also read your formal mail thread about kernel crash 
http://lkml.iu.edu/hypermail/linux/kernel/1203.1/03801.html, which seems 
to be crashed on the same line. Actually, I used the parameter of 
ecryptfs_passthrouth to enable plain test readable. Could you kindly 
give me some suggestion about how to quick debug or resolve this problem?



My method to mount ecryptfs file system is following:

mount -t ecryptfs ～/encrypt  ~/encrypt  -o ecryptfs_key_bytes=32 -o 
ecryptfs_cipher=aes -o no_sig_cache -o passphrase_passwd=%s -o 
ecryptfs_enable_filename_crypto=n  -o ecryptfs_passthrough -o key=passphrase


Detail crash information is:
--------------------------------------------------------------------------------------------------
[   87.924154] c3 kernel BUG at 
/home/abuild/rpmbuild/BUILD/kernel-pachira-3.4.5/kernel/fs/ecryptfs/crypto.c:464!
[   87.934258] c3 Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
[   87.940376] c3 Modules linked in: ittiam mali(O) ump(O)
[   87.945661] c3 CPU: 3    Tainted: G           O  (3.4.5 #1)
[   87.951261] c3 PC is at ecryptfs_encrypt_page+0x34/0x390
[   87.956646] c3 LR is at ecryptfs_writepage+0x4c/0x9c
[   87.961623] c3 pc : [<c0202a4c>]    lr : [<c0201574>]    psr: 40070013
[   87.961635] c3 sp : c37d3c50  ip : c37d3ce0  fp : c37d3cdc
[   87.973668] c3 r10: 00000000  r9 : db6f1948  r8 : c0fb1874
[   87.979199] c3 r7 : c0fb1874  r6 : dc914840  r5 : dc914918  r4 : dc9149c4
[   87.985985] c3 r3 : 00000003  r2 : c37d3ce0  r1 : c37d3e40  r0 : c0fb1874
[   87.992836] c3 Flags: nZcv  IRQs on  FIQs on  Mode SVC_32  ISA ARM 
Segment kernel
[   88.000477] c3 Control: 10c53c7d  Table: 9b6ec06a  DAC: 00000015
[   88.006497] c3
[   88.006503] c3 PC: 0xc02029cc:
[   88.011351] c3 29cc  e0614004 ea000003 e3560000 e0855004 15834008 
e3a04000 e2800001 e2833010
[   88.019773] c3 29ec  e1500007 a3a02000 b3a02001 e3540000 d3a02000 
e3520000 1affffd9 e3540000
[   88.028275] c3 2a0c  c3e0000b e89daff8 c0bea5d0 e1a0c00d e92ddff0 
e24cb004 e24dd064 e92d4000
......

[   89.134149] c3 [<c0202a4c>] (ecryptfs_encrypt_page+0x34/0x390) from 
[<c0201574>] (ecryptfs_writepage+0x4c/0x9c)
[   89.134173] c3 [<c0201574>] (ecryptfs_writepage+0x4c/0x9c) from 
[<c00e2a58>] (__writepage+0x24/0x48)
[   89.134195] c3 [<c00e2a58>] (__writepage+0x24/0x48) from [<c00e305c>] 
(write_cache_pages+0x2f4/0x404)
[   89.134215] c3 [<c00e305c>] (write_cache_pages+0x2f4/0x404) from 
[<c00e31bc>] (generic_writepages+0x50/0x6c)
[   89.134234] c3 [<c00e31bc>] (generic_writepages+0x50/0x6c) from 
[<c00e4934>] (do_writepages+0x3c/0x48)
[   89.134255] c3 [<c00e4934>] (do_writepages+0x3c/0x48) from 
[<c0143ca8>] (writeback_single_inode+0x1c4/0x40c)
[   89.134276] c3 [<c0143ca8>] (writeback_single_inode+0x1c4/0x40c) from 
[<c0144200>] (writeback_sb_inodes+0x15c/0x214)
[   89.134295] c3 [<c0144200>] (writeback_sb_inodes+0x15c/0x214) from 
[<c014432c>] (__writeback_inodes_wb+0x74/0xc0)
[   89.134315] c3 [<c014432c>] (__writeback_inodes_wb+0x74/0xc0) from 
[<c0144538>] (wb_writeback+0x1c0/0x364)
[   89.134333] c3 [<c0144538>] (wb_writeback+0x1c0/0x364) from 
[<c0144bd4>] (wb_do_writeback+0xf8/0x26c)
[   89.134352] c3 [<c0144bd4>] (wb_do_writeback+0xf8/0x26c) from 
[<c0144e34>] (bdi_writeback_thread+0xec/0x2e4)
[   89.134373] c3 [<c0144e34>] (bdi_writeback_thread+0xec/0x2e4) from 
[<c005f3d8>] (kthread+0x9c/0xa8)
[   89.134393] c3 [<c005f3d8>] (kthread+0x9c/0xa8) from [<c000ff54>] 
(kernel_thread_exit+0x0/0x8)
[   89.134408] c3 Code: e2864f61 e5963184 e3130004 1a000000 (e7f001f2)