Bug 14287 - ext4: fixpoint divide exception at ext4_fill_super
Summary: ext4: fixpoint divide exception at ext4_fill_super
Status: CLOSED CODE_FIX
Alias: None
Product: File System
Classification: Unclassified
Component: ext4 (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: fs_ext4@kernel-bugs.osdl.org
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2009-10-01 05:58 UTC by R.Nageswara Sastry
Modified: 2012-06-13 18:55 UTC (History)
2 users (show)

See Also:
Kernel Version: 2.6.32-rc1, 2.6.31
Subsystem:
Regression: No
Bisected commit-id:

Attachments
fsfuzzer image to recreate the kernel stack trace in tar gzipped format (760.06 KB, application/octet-stream)
2009-10-01 05:59 UTC, R.Nageswara Sastry 		Details
Patch which solves this fixpoint division exception (813 bytes, patch)
2009-11-04 12:54 UTC, R.Nageswara Sastry 		Details | Diff
Patch which solves this fixpoint division exception (1.06 KB, patch)
2009-11-04 14:05 UTC, R.Nageswara Sastry 		Details | Diff
Show Obsolete (1) Add an attachment (proposed patch, testcase, etc.)

Description R.Nageswara Sastry 2009-10-01 05:58:34 UTC 
Found kernel bug - fixpoint divide exception
While working with fsfuzzer

Environment: 2.6.31 and 2.6.32-rc1
Architecture: s390 and ppc64

------------[ cut here ]------------
Kernel BUG at 000003e00429d934 [verbose debug info unavailable]
fixpoint divide exception: 0009 [#1] SMP
Modules linked in: ext4 jbd2 crc16 loop autofs4 lockd sunrpc ipv6 qeth_l2 qeth
q
dio vmur ccwgroup dm_round_robin dm_multipath scsi_dh sd_mod scsi_mod multipath
dm_snapshot dm_zero dm_mirror dm_region_hash dm_log dm_mod dasd_fba_mod
dasd_eck
d_mod dasd_mod ext3 jbd
CPU: 2 Not tainted 2.6.31-rc6 #1
Process mount (pid: 2675, task: 000000003ed06038, ksp: 0000000036217920)
Krnl PSW : 0704200180000000 000003e00429d934 (ext4_fill_super+0x1478/0x2908
[ext
4])
           R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:0 CC:2 PM:0 EA:3
Krnl GPRS: 0000000000000100 0000000000000100 0000000000000006 000000002fc61800
           0000000000000000 0000000000000100 000000002fc61800 000000002fc61800
           000000003143a800 00000000000000e0 0000000000000000 000000003eb0d800
           000003e00427c000 000003e0042b8958 000003e00429d87c 0000000036217b10
Krnl Code: 000003e00429d928: b9160050           llgfr   %r5,%r0
           000003e00429d92c: a7490000           lghi    %r4,0
           000003e00429d930: b987004a           dlgr    %r4,%r10
          >000003e00429d934: b91600a5           llgfr   %r10,%r5
           000003e00429d938: a53f80d0           llill   %r3,32976
           000003e00429d93c: a7ad000c           mghi    %r10,12
           000003e00429d940: b904002a           lgr     %r2,%r10
           000003e00429d944: 1895               lr      %r9,%r5
Call Trace:
([<000003e00429d87c>] ext4_fill_super+0x13c0/0x2908 [ext4])
 [<00000000000f46f2>] get_sb_bdev+0x13e/0x19c
 [<000003e00429230e>] ext4_get_sb+0x2e/0x40 [ext4]
 [<00000000000f3f98>] vfs_kern_mount+0xc0/0x168
 [<00000000000f40ac>] do_kern_mount+0x58/0x114
 [<000000000010e558>] do_mount+0x798/0x830
 [<000000000010e6a0>] SyS_mount+0xb0/0x100
 [<00000000000266be>] sysc_noemu+0x10/0x16
 [<0000004e53f234e2>] 0x4e53f234e2
Last Breaking-Event-Address:
 [<000003e00429d8d8>] ext4_fill_super+0x141c/0x2908 [ext4]

---[ end trace b5563edf9c0c9b52 ]--- 

2.6.32-rc1 stack trace

------------[ cut here ]------------
Kernel BUG at 000003e0024d6b52 [verbose debug info unavailable]
fixpoint divide exception: 0009 [#1] SMP
Modules linked in: ext4 jbd2 crc16 autofs4 lockd sunrpc ipv6 loop qeth_l2 qeth vmur qdio ccwgroup dm_round_robin dm_multipath scsi_dh sd_mod scsi_mod multipath dm_snapshot dm_zero dm_mirror dm_region_hash dm_log dm_mod dasd_fba_mod dasd_eckd_mod dasd_mod ext3 jbd
CPU: 2 Not tainted 2.6.32-rc2 #1
Process mount (pid: 2752, task: 00000000233e47c0, ksp: 00000000233a3910)
Krnl PSW : 0704200180000000 000003e0024d6b52 (ext4_fill_super+0x1506/0x29c0 [ext4])
           R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:0 CC:2 PM:0 EA:3
Krnl GPRS: 0000000e00000100 0000000000000100 0000000000000006 00000000200ad000
           0000000000000000 0000000000000100 00000000200ad000 00000000200ad000
           00000000200ae000 000000001ab6d800 0000000000000000 00000000000000e0
           000003e0024b3000 000003e0024f2d28 000003e0024d6ab8 00000000233a3b00
Krnl Code: 000003e0024d6b46: b9160050           llgfr   %r5,%r0
           000003e0024d6b4a: a7490000           lghi    %r4,0
           000003e0024d6b4e: b987004a           dlgr    %r4,%r10
          >000003e0024d6b52: b91600b5           llgfr   %r11,%r5
           000003e0024d6b56: a53f80d0           llill   %r3,32976
           000003e0024d6b5a: a7bd000c           mghi    %r11,12
           000003e0024d6b5e: b904002b           lgr     %r2,%r11
           000003e0024d6b62: 18a5               lr      %r10,%r5
Call Trace:
([<000003e0024d6ab8>] ext4_fill_super+0x146c/0x29c0 [ext4])
 [<0000000000111ed8>] get_sb_bdev+0x158/0x1b4
 [<000003e0024cbe16>] ext4_get_sb+0x2e/0x40 [ext4]
 [<00000000001119ac>] vfs_kern_mount+0xc0/0x19c
 [<0000000000111af4>] do_kern_mount+0x58/0x114
 [<000000000012d760>] do_mount+0x7b4/0x84c
 [<000000000012d89c>] SyS_mount+0xa4/0xec
 [<0000000000027f5a>] sysc_tracego+0xe/0x14
 [<0000004e53f234e2>] 0x4e53f234e2
Last Breaking-Event-Address:
 [<000003e0024d6afa>] ext4_fill_super+0x14ae/0x29c0 [ext4]

---[ end trace b8c3330dd3812f17 ]---
Comment 1 R.Nageswara Sastry 2009-10-01 05:59:38 UTC 
Created attachment 23215 [details]
fsfuzzer image to recreate the kernel stack trace in tar gzipped format
Comment 2 R.Nageswara Sastry 2009-10-01 06:01:28 UTC 
Use the ext4.base file from already attached to other bug #14286
http://bugzilla.kernel.org/attachment.cgi?id=23214

unzip the above file(s) 
ext4.319.img.tar.gz
ext4.base.tar.gz 

And download the fsfuzzer from site http://www.risesecurity.org/files/fsfuzzer-0.7.3.tar.gz

Untar it
cd fsfuzzer-0.7.3
./configure
make

cp ext4.319.img to fsfuzzer-0.7.3/cfs
cp ext4.base to fsfuzzer-0.7.3/fs
and run the file named run_test in fsfuzzer-0.7.3
./run_test ext4 319

Check the dmesg.

Thanks!!
Comment 3 R.Nageswara Sastry 2009-10-16 12:29:42 UTC 
Any updates!!
Comment 4 Eric Sandeen 2009-10-16 23:41:07 UTC 
No updates, this issue is not as pressing as other things the ext4 development team is currently working on ...
Comment 5 R.Nageswara Sastry 2009-11-04 12:54:07 UTC 
Created attachment 23647 [details]
Patch which solves this fixpoint division exception
Comment 6 R.Nageswara Sastry 2009-11-04 14:05:14 UTC 
Created attachment 23648 [details]
Patch which solves this fixpoint division exception
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