I can confirm the same on my panda; note that when this hangs I did a ctrl-d in the serial console and got the following oops:

[20361.272521] Unable to handle kernel NULL pointer dereference at virtual address 0000009c
[20361.281005] pgd = d9d14000
[20361.283843] [0000009c] *pgd=8160c831, *pte=00000000, *ppte=00000000
[20361.290405] Internal error: Oops: 17 [#1] SMP
[20361.294921] last sysfs file: /sys/devices/system/cpu/cpu1/topology/core_siblings
[20361.302642] Modules linked in: smsc95xx usbnet omap_wdt omap2_mcspi leds_gpio twl4030_pwrbutton twl6030_usb usbhid usb_storage hid uas
[20361.315307] CPU: 0    Tainted: G        W    (2.6.38-1000-linaro-omap #1-Ubuntu)
[20361.322998] PC is at uart_update_termios+0xb0/0xc0
[20361.328033] LR is at tty_port_block_til_ready+0x170/0x2f4
[20361.333648] pc : [<c03973d8>]    lr : [<c03876b0>]    psr: 600f0013
[20361.333648] sp : da85dd70  ip : 00000000  fp : c1742800
[20361.345642] r10: 00000000  r9 : d9f89950  r8 : d9f8995c
[20361.351074] r7 : c1742800  r6 : da85c000  r5 : 00000000  r4 : c1403c00
[20361.357879] r3 : 00000000  r2 : 00000002  r1 : d9f89948  r0 : 00000002
[20361.364685] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
[20361.372131] Control: 10c53c7d  Table: 99d1404a  DAC: 00000015
[20361.378112] Process a.out (pid: 1371, stack limit = 0xda85c2f8)
[20361.384277] Stack: (0xda85dd70 to 0xda85e000)
[20361.388824] dd60:                                     d9f89948 c14888c0 da85c000 c03876b0
[20361.397369] dd80: c1742800 c015e720 80000013 d9f89948 00000002 00000000 c14ccf60 c00c6574
[20361.405883] dda0: da85dda0 da85dda0 00000000 0fc00002 c14888c0 00000000 da85c000 c1408060
[20361.414428] ddc0: c07e6b0c c0380aac 00000105 00000000 da0d9000 00000002 d9f6b788 d9f6b788
[20361.422943] dde0: 00000000 c1408060 00000000 c14888c0 da85c000 00000000 00000000 c016b2a8
[20361.431488] de00: c1408060 00000000 da85c000 c14888c0 da4ac800 c1488640 c1408060 00000000
[20361.440002] de20: da85c000 c016b194 00000000 c0165918 00000000 d9d4e700 00000000 c14888c0
[20361.448516] de40: da85ded4 00000024 da85c000 00000000 00000000 c01668fc d9d4e700 c01744f4
[20361.457061] de60: da85ded4 da85ded4 00000000 00000000 00000000 c0174688 da85ded4 00000000
[20361.465576] de80: 00000000 00000024 00000101 da85ded4 c16b4000 c0174bec 00100100 00200200
[20361.474121] dea0: 00000000 00000000 d9d15000 400effff c07ff960 ffffff9c 400f0000 da85df34
[20361.482635] dec0: c1729860 400e1000 d9c92318 da612d80 da612d70 c1488640 da4ac800 da612d70
[20361.491149] dee0: c6569a00 00000000 00000000 da5a6c00 00000000 c1408060 00000101 00000002
[20361.499694] df00: 00000001 00000000 400e0000 c005b4d4 00000010 c0168914 00000020 00000000
[20361.508209] df20: 400e1000 00000000 00000000 00000001 00000000 00000000 d9c92318 c07ababc
[20361.516754] df40: da82f380 da82f388 00000000 c16b4000 ffffff9c 00000003 00000005 00000000
[20361.525268] df60: da85c000 00000000 00000000 c0166960 00000000 400e1000 c1729860 beade91c
[20361.533813] df80: da85c000 00000000 beade7d8 000083a5 00000005 c0065e08 da85c000 00000000
[20361.542327] dfa0: 00000000 c0065c40 00000000 beade7d8 000084c0 00000000 beade91c 00008425
[20361.550872] dfc0: 00000000 beade7d8 000083a5 00000005 00000000 00000000 400e0000 00000000
[20361.559387] dfe0: beade7b0 beade7b0 0000843f 4020c5dc 40000010 000084c0 f1bbc32c bf080f00
[20361.567932] [<c03973d8>] (uart_update_termios+0xb0/0xc0) from [<c03876b0>] (tty_port_block_til_ready+0x170/0x2f4)
[20361.578643] [<c03876b0>] (tty_port_block_til_ready+0x170/0x2f4) from [<c0380aac>] (tty_open+0x178/0x420)
[20361.588531] [<c0380aac>] (tty_open+0x178/0x420) from [<c016b2a8>] (chrdev_open+0x114/0x1ec)
[20361.597290] [<c016b2a8>] (chrdev_open+0x114/0x1ec) from [<c0165918>] (__dentry_open+0x100/0x2b8)
[20361.606445] [<c0165918>] (__dentry_open+0x100/0x2b8) from [<c01668fc>] (nameidata_to_filp+0x60/0x68)
[20361.615997] [<c01668fc>] (nameidata_to_filp+0x60/0x68) from [<c0174688>] (finish_open+0xa0/0x174)
[20361.625244] [<c0174688>] (finish_open+0xa0/0x174) from [<c0174bec>] (do_filp_open+0x18c/0x5f8)
[20361.634216] [<c0174bec>] (do_filp_open+0x18c/0x5f8) from [<c0166960>] (do_sys_open+0x5c/0x138)
[20361.643218] [<c0166960>] (do_sys_open+0x5c/0x138) from [<c0065c40>] (ret_fast_syscall+0x0/0x30)
[20361.652282] Code: 15823008 13a02000 15943068 1583202c (e595209c) 
[20361.658691] ---[ end trace 7cd7f1d7fe091943 ]---