Xen- linux-ubuntu-modules unionfs issue - kernel NULL pointer dereference

[Arun Sharma]

Hello

I am facing one problem with unionfs. The bug description is given below.
Most often i found unionfs throws kernel NULL pointer dereference error.
Till now i am not sure what is this problem all about.

I have used below packages but still i can't find any luck. Any clue will be
helpfull.
linux-ubuntu-modules-2.6.24-24-xen
linux-ubuntu-modules-2.6.24-22-xen
linux-ubuntu-modules-2.6.24-19-xen


[   50.865463] Unable to handle kernel NULL pointer dereference at
0000000000000010 RIP:
[   50.865476]  [<ffffffff88007246>] :unionfs:newputmap+0xf6/0x1b0
[   50.865489] PGD 186d3067 PUD 18f49067 PMD 0
[   50.865494] Oops: 0002 [1] SMP
[   50.865497] CPU 0
[   50.865499] Modules linked in: af_packet ipt_REJECT xt_tcpudp
nf_conntrack_ipv4 xt_state nf_conntrack iptable_filter ip_tables x_tables
evdev ext3 jbd mbcache unionfs
[   50.865512] Pid: 3940, comm: unionctl Not tainted 2.6.24-24-xen #1
[   50.865515] RIP: e030:[<ffffffff88007246>]  [<ffffffff88007246>]
:unionfs:newputmap+0xf6/0x1b0
[   50.865521] RSP: e02b:ffff88001851fbb8  EFLAGS: 00010246
[   50.865523] RAX: 0000000000000000 RBX: 0000000000000002 RCX:
0000000000000002
[   50.865526] RDX: 0000000000000010 RSI: 0000000000000002 RDI:
0000000000000000
[   50.865528] RBP: ffff880019685200 R08: ffff8800197260f0 R09:
0000000000000002
[   50.865530] R10: 0000000000000001 R11: ffffffff8031e6a0 R12:
ffff88001951fd00
[   50.865533] R13: ffff880019726000 R14: 0000000000000010 R15:
0000000000000000
[   50.865537] FS:  00007fc0c2fc56e0(0000) GS:ffffffff805c7000(0000)
knlGS:0000000000000000
[   50.865539] CS:  e033 DS: 0000 ES: 0000
[   50.865541] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
0000000000000000
[   50.865543] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7:
0000000000000000
[   50.865546] Process unionctl (pid: 3940, threadinfo ffff88001851e000,
task ffff8800177b5040)
[   50.865549] Stack:  ffff880018ad34e0 ffff880019726000 0000000000000000
00000000ffffffea
[   50.865554]  0000000000000000 ffffffff8800781f 0000000000000000
ffff880017a05000
[   50.865558]  0000000000000020 ffffffff802bf184 0000000000000000
0000000000000001
[   50.865562] Call Trace:
[   50.865568]  [<ffffffff8800781f>]
:unionfs:unionfs_ioctl_delbranch+0xcf/0x410
[   50.865575]  [<ffffffff802bf184>] sync_inodes_sb+0x94/0xb0
[   50.865579]  [<ffffffff8029f975>] do_remount_sb+0xd5/0x150
[   50.865583]  [<ffffffff802b777c>] do_mount+0x4ac/0x810
[   50.865587]  [<ffffffff80272e0d>] find_lock_page+0x3d/0x110
[   50.865590]  [<ffffffff802752e3>] filemap_fault+0x1d3/0x3e0
[   50.865595]  [<ffffffff8033a211>] __up_read+0x21/0xb0
[   50.865600]  [<ffffffff8024a6ed>] search_exception_tables+0x1d/0x30
[   50.865604]  [<ffffffff80473ddb>] do_page_fault+0x3eb/0x11e0
[   50.865608]  [<ffffffff80287741>] handle_mm_fault+0x1d1/0xd60
[   50.865611]  [<ffffffff802a912a>] do_path_lookup+0x8a/0x250
[   50.865614]  [<ffffffff80278540>] get_page_from_freelist+0xc0/0x520
[   50.865618]  [<ffffffff80278acd>] __alloc_pages+0x9d/0x3c0
[   50.865622]  [<ffffffff80278e77>] __get_free_pages+0x87/0xa0
[   50.865625]  [<ffffffff802b822b>] sys_mount+0x9b/0x100
[   50.865629]  [<ffffffff8020c698>] system_call+0x68/0x6d
[   50.865631]  [<ffffffff8020c630>] system_call+0x0/0x6d
[   50.865634]
[   50.865635]
[   50.865635] Code: 4c 89 24 c2 31 c0 5b 5d 41 5c 41 5d 41 5e c3 48 8b 45
38 48
[   50.865645] RIP  [<ffffffff88007246>] :unionfs:newputmap+0xf6/0x1b0
[   50.865651]  RSP <ffff88001851fbb8>
[   50.865653] CR2: 0000000000000010
[   50.865660] ---[ end trace d89be748ddf857e4 ]---
[   50.865663] WARNING: at
/build/buildd/linux-2.6.24/debian/build/custom-source-xen/kernel/exit.c:917
do_exit()
[   50.865667] Pid: 3940, comm: unionctl Tainted: G      D 2.6.24-24-xen #1
[   50.865669]
[   50.865669] Call Trace:
[   50.865672]  [<ffffffff8023971e>] do_exit+0x7de/0x9a0
[   50.865676]  [<ffffffff804743b6>] do_page_fault+0x9c6/0x11e0
[   50.865680]  [<ffffffff802e0fe3>] task_dumpable+0x23/0x40
[   50.865685]  [<ffffffff802b1b9b>] dput+0xab/0x140
[   50.865687]  [<ffffffff802a5eb9>] __follow_mount+0x29/0xa0
[   50.865690]  [<ffffffff802a610f>] do_lookup+0x8f/0x250
[   50.865693]  [<ffffffff80472287>] error_exit+0x0/0x79
[   50.865697]  [<ffffffff8031e6a0>] apparmor_capable+0x0/0x50
[   50.865702]  [<ffffffff88007246>] :unionfs:newputmap+0xf6/0x1b0
[   50.865707]  [<ffffffff880072cb>] :unionfs:newputmap+0x17b/0x1b0
[   50.865713]  [<ffffffff8800781f>]
:unionfs:unionfs_ioctl_delbranch+0xcf/0x410
[   50.865716]  [<ffffffff802bf184>] sync_inodes_sb+0x94/0xb0
[   50.865720]  [<ffffffff8029f975>] do_remount_sb+0xd5/0x150
[   50.865723]  [<ffffffff802b777c>] do_mount+0x4ac/0x810
[   50.865726]  [<ffffffff80272e0d>] find_lock_page+0x3d/0x110
[   50.865728]  [<ffffffff802752e3>] filemap_fault+0x1d3/0x3e0
[   50.865732]  [<ffffffff8033a211>] __up_read+0x21/0xb0
[   50.865735]  [<ffffffff8024a6ed>] search_exception_tables+0x1d/0x30
[   50.865738]  [<ffffffff80473ddb>] do_page_fault+0x3eb/0x11e0
[   50.865741]  [<ffffffff80287741>] handle_mm_fault+0x1d1/0xd60
[   50.865743]  [<ffffffff802a912a>] do_path_lookup+0x8a/0x250
[   50.865746]  [<ffffffff80278540>] get_page_from_freelist+0xc0/0x520
[   50.865750]  [<ffffffff80278acd>] __alloc_pages+0x9d/0x3c0
[   50.865753]  [<ffffffff80278e77>] __get_free_pages+0x87/0xa0
[   50.865756]  [<ffffffff802b822b>] sys_mount+0x9b/0x100
[   50.865759]  [<ffffffff8020c698>] system_call+0x68/0x6d
[   50.865761]  [<ffffffff8020c630>] system_call+0x0/0x6d
[   50.865763]
Killed

-- 
Regards
Arun Sharma
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