Thanks for sending me an Apple crash report. Let’s take a look at it. To start, here’s the exception information:
Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Subtype: KERN_INVALID_ADDRESS at 0x0000000000000000
Triggered by Thread: 68
This is a memory access exception at 0. Now let’s look at the crashing thread:
Thread 68 Crashed:
Thread 69:
Oi vey! no backtrace. Now let’s look at the state of the CPU ta the time of the crash.
Thread 68 crashed with ARM Thread State (64-bit):
x0: 0x0000000000000000 x1: 0x0000000000000000 x2: 0x0000000000000100 x3: 0x000000000091ce30
x4: 0x0000000000002060 x5: 0x0000000000000060 x6: 0x0000000000000000 x7: 0x0000000000000000
x8: 0xffffffffffffffff x9: 0x0000000000000000 x10: 0x0000000000000003 x11: 0x0000020000000303
x12: 0x0000000000000000 x13: 0x0000000000000300 x14: 0x0000010000000100 x15: 0x0000000000000000
x16: 0x000000000000012d x17: 0x0000000000000000 x18: 0x0000000000000000 x19: 0x0000000000000000
x20: 0x0000000000000000 x21: 0x0000000000000000 x22: 0x0000000000000000 x23: 0x0000000000000000
x24: 0x0000000000000000 x25: 0x0000000000000000 x26: 0x0000000000000000 x27: 0x0000000106be31b8
x28: 0x000000011bdd6060 fp: 0x0000000000000000 lr: 0x0000000000000000
sp: 0x000000017162eea0 pc: 0x0000000000000000 cpsr: 0x60000000
As you can see, most of the CPU registers have been cleared. That’s not good. Specifically:
pc
— This is the immediate cause of the crash; you’ve jumped to address 0 and have thus crashed trying to fetch instructions from that unmapped memory.lr
— Normally a jump like this leaves the return address in this register, and the crash reporter can start a backtrace based on that. However, in this case the value is also 0.
It’s hard to say how you got into this state, but the usual reason for this sort of thing is that you’ve smashed your stack horribly, and thus crashed after restoring the CPU state from that stack.
As to what to do now, I recommend that you focus on your efforts on
sp
, which looks like a valid stack pointer. With a bit of grovelling through that stack you should be able to build a manual backtrace.
Share and Enjoy
—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware
let myEmail = "eskimo" + "1" + "@apple.com"