I have the same problem. I have had several crashes with Safari since I updated to ios 5.
It ocurrs normally when I am typying long text in a web (forum, etc)
Here is the bug reports,
Incident Identifier: 1D14F923-262F-482D-A6D1-3144EAB293B9
CrashReporter Key: 572f1f51d2605b398661049dbfd85dddf454395c
Hardware Model: iPad2,1
Process: MobileSafari [7100]
Path: /Applications/MobileSafari.app/MobileSafari
Identifier: MobileSafari
Version: ??? (???)
Code Type: ARM (Native)
Parent Process: launchd [1]
Exception Type: EXC_BAD_ACCESS (SIGBUS)
Exception Codes: KERN_PROTECTION_FAILURE at 0x03aebde0
Crashed Thread: 10
Thread 10 name: Dispatch queue: CA::CG::Queue
Thread 10 Crashed:
0 ??? 0x03aebde0 0 + 61783520
1 CoreGraphics 0x372bdd54 0x37276000 + 294228
2 QuartzCore 0x3648975c 0x36448000 + 268124
3 QuartzCore 0x36489674 0x36448000 + 267892
4 QuartzCore 0x364825ec 0x36448000 + 239084
5 QuartzCore 0x36481abe 0x36448000 + 236222
6 QuartzCore 0x3648062e 0x36448000 + 230958
7 libdispatch.dylib 0x35e79dc0 0x35e77000 + 11712
8 libdispatch.dylib 0x35e79c56 0x35e77000 + 11350
9 libdispatch.dylib 0x35e7a860 0x35e77000 + 14432
10 libsystem_c.dylib 0x30a821c8 0x30a78000 + 41416
11 libsystem_c.dylib 0x30a8209c 0x30a78000 + 41116
Thread 10 crashed with ARM Thread State:
r0: 0x02933b10 r1: 0x2ff70b80 r2: 0x03aebde0 r3: 0x00000000
r4: 0x00000000 r5: 0x002c5e80 r6: 0x00000001 r7: 0x2ff70b24
r8: 0x00198e00 r9: 0x13b6a1d0 r10: 0x028121a0 r11: 0x03540688
ip: 0x3f9f8944 sp: 0x2ff70b24 lr: 0x372bdd6d pc: 0x03aebde0
cpsr: 0x00000010