Hello <br><br>I am facing one problem with unionfs. The bug description is given below. Most often i found unionfs throws kernel NULL pointer dereference error. <br>Till now i am not sure what is this problem all about.<br>
<br>I have used below packages but still i can&#39;t find any luck. Any clue will be helpfull.<br>linux-ubuntu-modules-2.6.24-24-xen<br>linux-ubuntu-modules-2.6.24-22-xen<br>linux-ubuntu-modules-2.6.24-19-xen<br><br><br clear="all">
<span style="color: rgb(204, 0, 0);">[   50.865463] Unable to handle kernel NULL pointer dereference at 0000000000000010 RIP: </span><br>[   50.865476]  [&lt;ffffffff88007246&gt;] :unionfs:newputmap+0xf6/0x1b0<br>[   50.865489] PGD 186d3067 PUD 18f49067 PMD 0 <br>
[   50.865494] Oops: 0002 [1] SMP <br>[   50.865497] CPU 0 <br>[   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<br>
[   50.865512] Pid: 3940, comm: unionctl Not tainted 2.6.24-24-xen #1<br>[   50.865515] RIP: e030:[&lt;ffffffff88007246&gt;]  [&lt;ffffffff88007246&gt;] :unionfs:newputmap+0xf6/0x1b0<br>[   50.865521] RSP: e02b:ffff88001851fbb8  EFLAGS: 00010246<br>
[   50.865523] RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000002<br>[   50.865526] RDX: 0000000000000010 RSI: 0000000000000002 RDI: 0000000000000000<br>[   50.865528] RBP: ffff880019685200 R08: ffff8800197260f0 R09: 0000000000000002<br>
[   50.865530] R10: 0000000000000001 R11: ffffffff8031e6a0 R12: ffff88001951fd00<br>[   50.865533] R13: ffff880019726000 R14: 0000000000000010 R15: 0000000000000000<br>[   50.865537] FS:  00007fc0c2fc56e0(0000) GS:ffffffff805c7000(0000) knlGS:0000000000000000<br>
[   50.865539] CS:  e033 DS: 0000 ES: 0000<br>[   50.865541] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000<br>[   50.865543] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000000<br>[   50.865546] Process unionctl (pid: 3940, threadinfo ffff88001851e000, task ffff8800177b5040)<br>
[   50.865549] Stack:  ffff880018ad34e0 ffff880019726000 0000000000000000 00000000ffffffea<br>[   50.865554]  0000000000000000 ffffffff8800781f 0000000000000000 ffff880017a05000<br>[   50.865558]  0000000000000020 ffffffff802bf184 0000000000000000 0000000000000001<br>
[   50.865562] Call Trace:<br>[   50.865568]  [&lt;ffffffff8800781f&gt;] :unionfs:unionfs_ioctl_delbranch+0xcf/0x410<br>[   50.865575]  [&lt;ffffffff802bf184&gt;] sync_inodes_sb+0x94/0xb0<br>[   50.865579]  [&lt;ffffffff8029f975&gt;] do_remount_sb+0xd5/0x150<br>
[   50.865583]  [&lt;ffffffff802b777c&gt;] do_mount+0x4ac/0x810<br>[   50.865587]  [&lt;ffffffff80272e0d&gt;] find_lock_page+0x3d/0x110<br>[   50.865590]  [&lt;ffffffff802752e3&gt;] filemap_fault+0x1d3/0x3e0<br>[   50.865595]  [&lt;ffffffff8033a211&gt;] __up_read+0x21/0xb0<br>
[   50.865600]  [&lt;ffffffff8024a6ed&gt;] search_exception_tables+0x1d/0x30<br>[   50.865604]  [&lt;ffffffff80473ddb&gt;] do_page_fault+0x3eb/0x11e0<br>[   50.865608]  [&lt;ffffffff80287741&gt;] handle_mm_fault+0x1d1/0xd60<br>
[   50.865611]  [&lt;ffffffff802a912a&gt;] do_path_lookup+0x8a/0x250<br>[   50.865614]  [&lt;ffffffff80278540&gt;] get_page_from_freelist+0xc0/0x520<br>[   50.865618]  [&lt;ffffffff80278acd&gt;] __alloc_pages+0x9d/0x3c0<br>
[   50.865622]  [&lt;ffffffff80278e77&gt;] __get_free_pages+0x87/0xa0<br>[   50.865625]  [&lt;ffffffff802b822b&gt;] sys_mount+0x9b/0x100<br>[   50.865629]  [&lt;ffffffff8020c698&gt;] system_call+0x68/0x6d<br>[   50.865631]  [&lt;ffffffff8020c630&gt;] system_call+0x0/0x6d<br>
[   50.865634] <br>[   50.865635] <br>[   50.865635] Code: 4c 89 24 c2 31 c0 5b 5d 41 5c 41 5d 41 5e c3 48 8b 45 38 48 <br>[   50.865645] RIP  [&lt;ffffffff88007246&gt;] :unionfs:newputmap+0xf6/0x1b0<br>[   50.865651]  RSP &lt;ffff88001851fbb8&gt;<br>
[   50.865653] CR2: 0000000000000010<br>[   50.865660] ---[ end trace d89be748ddf857e4 ]---<br>[   50.865663] WARNING: at /build/buildd/linux-2.6.24/debian/build/custom-source-xen/kernel/exit.c:917 do_exit()<br>[   50.865667] Pid: 3940, comm: unionctl Tainted: G      D 2.6.24-24-xen #1<br>
[   50.865669] <br>[   50.865669] Call Trace:<br>[   50.865672]  [&lt;ffffffff8023971e&gt;] do_exit+0x7de/0x9a0<br>[   50.865676]  [&lt;ffffffff804743b6&gt;] do_page_fault+0x9c6/0x11e0<br>[   50.865680]  [&lt;ffffffff802e0fe3&gt;] task_dumpable+0x23/0x40<br>
[   50.865685]  [&lt;ffffffff802b1b9b&gt;] dput+0xab/0x140<br>[   50.865687]  [&lt;ffffffff802a5eb9&gt;] __follow_mount+0x29/0xa0<br>[   50.865690]  [&lt;ffffffff802a610f&gt;] do_lookup+0x8f/0x250<br>[   50.865693]  [&lt;ffffffff80472287&gt;] error_exit+0x0/0x79<br>
[   50.865697]  [&lt;ffffffff8031e6a0&gt;] apparmor_capable+0x0/0x50<br>[   50.865702]  [&lt;ffffffff88007246&gt;] :unionfs:newputmap+0xf6/0x1b0<br>[   50.865707]  [&lt;ffffffff880072cb&gt;] :unionfs:newputmap+0x17b/0x1b0<br>
[   50.865713]  [&lt;ffffffff8800781f&gt;] :unionfs:unionfs_ioctl_delbranch+0xcf/0x410<br>[   50.865716]  [&lt;ffffffff802bf184&gt;] sync_inodes_sb+0x94/0xb0<br>[   50.865720]  [&lt;ffffffff8029f975&gt;] do_remount_sb+0xd5/0x150<br>
[   50.865723]  [&lt;ffffffff802b777c&gt;] do_mount+0x4ac/0x810<br>[   50.865726]  [&lt;ffffffff80272e0d&gt;] find_lock_page+0x3d/0x110<br>[   50.865728]  [&lt;ffffffff802752e3&gt;] filemap_fault+0x1d3/0x3e0<br>[   50.865732]  [&lt;ffffffff8033a211&gt;] __up_read+0x21/0xb0<br>
[   50.865735]  [&lt;ffffffff8024a6ed&gt;] search_exception_tables+0x1d/0x30<br>[   50.865738]  [&lt;ffffffff80473ddb&gt;] do_page_fault+0x3eb/0x11e0<br>[   50.865741]  [&lt;ffffffff80287741&gt;] handle_mm_fault+0x1d1/0xd60<br>
[   50.865743]  [&lt;ffffffff802a912a&gt;] do_path_lookup+0x8a/0x250<br>[   50.865746]  [&lt;ffffffff80278540&gt;] get_page_from_freelist+0xc0/0x520<br>[   50.865750]  [&lt;ffffffff80278acd&gt;] __alloc_pages+0x9d/0x3c0<br>
[   50.865753]  [&lt;ffffffff80278e77&gt;] __get_free_pages+0x87/0xa0<br>[   50.865756]  [&lt;ffffffff802b822b&gt;] sys_mount+0x9b/0x100<br>[   50.865759]  [&lt;ffffffff8020c698&gt;] system_call+0x68/0x6d<br>[   50.865761]  [&lt;ffffffff8020c630&gt;] system_call+0x0/0x6d<br>
[   50.865763] <br>Killed<br><br>-- <br>Regards<br>Arun Sharma<br><br>