While toying with the idea of backporting and enabling fsc support in
RHEL6, I did some testing of the fsc code in 2.6.39. I mounted a
filesystem with the following mount options "sec=krb5i,multiuser,fsc".
I then logged in as an unprivileged user and got a krb5 ticket and ran
the fsstress program from LTP on the filesystem:
$ fsstress -d /mnt/cifs/fsstress -n1000 -p8 -l0
...a few seconds later, the box crashed with the following oopses. This
is easily reproducible, and seems to crash within a few seconds of
kicking off the program:
[ 417.277296] CacheFiles: Error: Unexpected object collision
[ 417.278586] object: OBJ92
[ 417.279594] objstate=OBJECT_LOOKING_UP fl=0 wbusy=2 ev=0[7b]
[ 417.286253] ops=0 inp=0 exc=0
[ 417.286986] parent=ffff880018384180
[ 417.287896] cookie=ffff88002bb8d8c0 [pr=ffff88002bb8d0a0 nd=ffff88002af01020 fl=7]
[ 417.290298] key=[8] '2501020000000000'
[ 417.291548] xobject: OBJ91
[ 417.292636] xobjstate=OBJECT_RECYCLING fl=0 wbusy=2 ev=20[1]
[ 417.297511] xops=0 inp=0 exc=0
[ 417.298875] xparent=ffff880018384180
[ 417.300769] xcookie=NULL
[ 417.302635] ------------[ cut here ]------------
[ 417.304903] kernel BUG at fs/cachefiles/namei.c:201!
[ 417.307613] invalid opcode: 0000 [#1] SMP
[ 417.309860] last sysfs file: /sys/devices/system/cpu/cpu1/cache/index2/shared_cpu_map
[ 417.313868] CPU 1
[ 417.314855] Modules linked in: fuse nls_utf8 cifs sunrpc cachefiles fscache ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables joydev microcode i2c_piix4 virtio_balloon i2c_core virtio_net ipv6 virtio_blk [last unloaded: mperf]
[ 417.328983]
[ 417.329923] Pid: 5, comm: kworker/u:0 Not tainted 2.6.38.7-30.fc15.x86_64 #1 Bochs Bochs
[ 417.333928] RIP: 0010:[<ffffffffa00bebe4>] [<ffffffffa00bebe4>] cachefiles_walk_to_object+0x436/0x745 [cachefiles]
[ 417.338967] RSP: 0018:ffff88002ce6dd00 EFLAGS: 00010282
[ 417.341761] RAX: ffff88002ef165f0 RBX: ffff88001811f500 RCX: 0000000000000000
[ 417.344943] RDX: 0000000000000000 RSI: 0000000000000100 RDI: 0000000000000282
[ 417.348639] RBP: ffff88002ce6dda0 R08: 0000000000000100 R09: ffffffff81b3a300
[ 417.351813] R10: 0000ffff00066c0a R11: 0000000000000003 R12: ffff88002ae54840
[ 417.355522] R13: ffff88002ae54840 R14: ffff880029c29c00 R15: ffff88001811f4b0
[ 417.358879] FS: 00007f394dd32720(0000) GS:ffff88002ef00000(0000) knlGS:0000000000000000
[ 417.362780] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 417.365651] CR2: 00007fffcb62ddf8 CR3: 000000001825f000 CR4: 00000000000006e0
[ 417.368830] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 417.372688] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[ 417.375876] Process kworker/u:0 (pid: 5, threadinfo ffff88002ce6c000, task ffff88002ce55cc0)
[ 417.379863] Stack:
[ 417.380891] 0000000000000246 ffff88002ce55cc0 ffff88002ce6dd58 ffff88001815dc00
[ 417.384864] ffff8800185246c0 ffff88001811f618 ffff880029c29d18 ffff88001811f380
[ 417.388935] ffff88002ce6dd50 ffffffff814757e4 ffff88002ce6dda0 ffffffff8106ac56
[ 417.392907] Call Trace:
[ 417.394580] [<ffffffff814757e4>] ? _raw_spin_unlock_irqrestore+0x17/0x19
[ 417.397739] [<ffffffff8106ac56>] ? __queue_work+0x256/0x265
[ 417.400607] [<ffffffffa00bd91f>] cachefiles_lookup_object+0x78/0xd4 [cachefiles]
[ 417.403898] [<ffffffffa00a9977>] ? fscache_object_work_func+0x0/0x669 [fscache]
[ 417.407659] [<ffffffffa00a95da>] fscache_lookup_object+0x131/0x16d [fscache]
[ 417.410832] [<ffffffffa00a9b33>] fscache_object_work_func+0x1bc/0x669 [fscache]
[ 417.414598] [<ffffffffa00a9977>] ? fscache_object_work_func+0x0/0x669 [fscache]
[ 417.417956] [<ffffffff8106afb6>] process_one_work+0x186/0x298
[ 417.420876] [<ffffffff8106b343>] worker_thread+0xda/0x15d
[ 417.423693] [<ffffffff8106b269>] ? worker_thread+0x0/0x15d
[ 417.426546] [<ffffffff8106b269>] ? worker_thread+0x0/0x15d
[ 417.428877] [<ffffffff8106ebaf>] kthread+0x84/0x8c
[ 417.431712] [<ffffffff8100a9e4>] kernel_thread_helper+0x4/0x10
[ 417.434615] [<ffffffff8106eb2b>] ? kthread+0x0/0x8c
[ 417.436809] [<ffffffff8100a9e0>] ? kernel_thread_helper+0x0/0x10
[ 417.439746] Code: 05 77 2a 48 c7 c7 ce 1c 0c a0 31 c0 e8 c6 db 3a e1 48 c7 c7 77 1f 0c a0 31 c0 e8 b8 db 3a e1 48 8b 75 98 48 89 df e8 ae 23 00 00 <0f> 0b 48 8b 55 98 f0 ff 82 20 01 00 00 48 8b 7d 90 e8 86 f5 ff
[ 417.453802] RIP [<ffffffffa00bebe4>] cachefiles_walk_to_object+0x436/0x745 [cachefiles]
[ 417.457781] RSP <ffff88002ce6dd00>
[ 417.459638] ---[ end trace 1d481c9af1804caa ]---
[ 417.462614] BUG: unable to handle kernel paging request at fffffffffffffff8
[ 417.462726] IP: [<ffffffff8106ee03>] kthread_data+0x11/0x16
[ 417.462726] PGD 1a05067 PUD 1a06067 PMD 0
[ 417.462726] Oops: 0000 [#2] SMP
[ 417.462726] last sysfs file: /sys/devices/system/cpu/cpu1/cache/index2/shared_cpu_map
[ 417.462726] CPU 1
[ 417.462726] Modules linked in: fuse nls_utf8 cifs sunrpc cachefiles fscache ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables joydev microcode i2c_piix4 virtio_balloon i2c_core virtio_net ipv6 virtio_blk [last unloaded: mperf]
[ 417.462726]
[ 417.462726] Pid: 5, comm: kworker/u:0 Tainted: G D 2.6.38.7-30.fc15.x86_64 #1 Bochs Bochs
[ 417.462726] RIP: 0010:[<ffffffff8106ee03>] [<ffffffff8106ee03>] kthread_data+0x11/0x16
[ 417.462726] RSP: 0018:ffff88002ce6d9a0 EFLAGS: 00010002
[ 417.462726] RAX: 0000000000000000 RBX: ffff88002ef13840 RCX: ffff88002ce55cc0
[ 417.462726] RDX: ffff88002ce55cc0 RSI: 0000000000000001 RDI: ffff88002ce55cc0
[ 417.462726] RBP: ffff88002ce6d9c8 R08: dead000000200200 R09: dead000000200200
[ 417.462726] R10: dead000000200200 R11: ffffea00009d2500 R12: 0000000000000001
[ 417.462726] R13: 0000000000000000 R14: ffff88002ce56078 R15: 0000000000000001
[ 417.462726] FS: 00007f585ab51700(0000) GS:ffff88002ef00000(0000) knlGS:0000000000000000
[ 417.462726] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 417.462726] CR2: fffffffffffffff8 CR3: 000000002b29b000 CR4: 00000000000006e0
[ 417.462726] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 417.462726] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[ 417.462726] Process kworker/u:0 (pid: 5, threadinfo ffff88002ce6c000, task ffff88002ce55cc0)
[ 417.462726] Stack:
[ 417.462726] ffffffff8106bb62 dead000000200200 ffff88002ef13840 ffff88002ce56290
[ 417.462726] 0000000000000000 ffff88002ce6da58 ffffffff81473c8c 0000000000000000
[ 417.462726] ffff88002ce55cc0 ffff88002ce6dfd8 ffff88002ce6dfd8 0000000000013840
[ 417.462726] Call Trace:
[ 417.462726] [<ffffffff8106bb62>] ? wq_worker_sleeping+0x18/0x82
[ 417.462726] [<ffffffff81473c8c>] schedule+0x181/0x66a
[ 417.462726] [<ffffffff81072ffa>] ? switch_task_namespaces+0x48/0x61
[ 417.462726] [<ffffffff81058b4d>] do_exit+0x730/0x732
[ 417.462726] [<ffffffff81476ace>] oops_end+0xbc/0xc5
[ 417.462726] [<ffffffff8100d454>] die+0x5a/0x66
[ 417.462726] [<ffffffff814763c8>] do_trap+0x121/0x130
[ 417.462726] [<ffffffff8100aeaa>] do_invalid_op+0x94/0x9d
[ 417.462726] [<ffffffffa00bebe4>] ? cachefiles_walk_to_object+0x436/0x745 [cachefiles]
[ 417.462726] [<ffffffff8146c7e1>] ? printk+0x51/0x53
[ 417.462726] [<ffffffff8100a85b>] invalid_op+0x1b/0x20
[ 417.462726] [<ffffffffa00bebe4>] ? cachefiles_walk_to_object+0x436/0x745 [cachefiles]
[ 417.462726] [<ffffffff814757e4>] ? _raw_spin_unlock_irqrestore+0x17/0x19
[ 417.462726] [<ffffffff8106ac56>] ? __queue_work+0x256/0x265
[ 417.462726] [<ffffffffa00bd91f>] cachefiles_lookup_object+0x78/0xd4 [cachefiles]
[ 417.462726] [<ffffffffa00a9977>] ? fscache_object_work_func+0x0/0x669 [fscache]
[ 417.462726] [<ffffffffa00a95da>] fscache_lookup_object+0x131/0x16d [fscache]
[ 417.462726] [<ffffffffa00a9b33>] fscache_object_work_func+0x1bc/0x669 [fscache]
[ 417.462726] [<ffffffffa00a9977>] ? fscache_object_work_func+0x0/0x669 [fscache]
[ 417.462726] [<ffffffff8106afb6>] process_one_work+0x186/0x298
[ 417.462726] [<ffffffff8106b343>] worker_thread+0xda/0x15d
[ 417.462726] [<ffffffff8106b269>] ? worker_thread+0x0/0x15d
[ 417.462726] [<ffffffff8106b269>] ? worker_thread+0x0/0x15d
[ 417.462726] [<ffffffff8106ebaf>] kthread+0x84/0x8c
[ 417.462726] [<ffffffff8100a9e4>] kernel_thread_helper+0x4/0x10
[ 417.462726] [<ffffffff8106eb2b>] ? kthread+0x0/0x8c
[ 417.462726] [<ffffffff8100a9e0>] ? kernel_thread_helper+0x0/0x10
[ 417.462726] Code: 29 e6 f3 a5 c7 83 ac 01 00 00 01 00 00 00 81 4b 14 00 00 00 04 5b 41 5c 5d c3 55 48 89 e5 66 66 66 66 90 48 8b 87 60 03 00 00 5d
[ 417.462726] 8b 40 f8 c3 55 48 89 e5 41 56 41 55 41 54 53 48 83 ec 50 66
[ 417.462726] RIP [<ffffffff8106ee03>] kthread_data+0x11/0x16
[ 417.462726] RSP <ffff88002ce6d9a0>
[ 417.462726] CR2: fffffffffffffff8
[ 417.462726] ---[ end trace 1d481c9af1804cab ]---
[ 417.462726] Fixing recursive fault but reboot is needed!
--
Jeff Layton <jlayton@xxxxxxxxxx>
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