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ion crashes with a page fault after login

Created by: nihathrael

  • [x ] I agree that I have searched opened and closed issues to prevent duplicates.

Description

ion crashes with a page fault on login in the terminal or when starting obital in the UI.

Environment info

  • Arch Linux
  • qemu and virtualbox
  • Operating system: Arch Linux
  • uname -a: Linux reaper 4.14.6-1-ARCH #1 SMP PREEMPT Thu Dec 14 21:26:16 UTC 2017 x86_64 GNU/Linux
  • rustc -V: rustc 1.24.0-nightly (dc39c3169 2017-12-17)
  • git rev-parse HEAD: ee7b0462a37897545114f1bdd41dc48530ffc2f1 (HEAD at December 19th 2017)

Steps to reproduce

  1. Launch redox make qemu vga=none
  2. login
  3. see pagefault on launch of ion

OR

  1. Launch redox make qemu
  2. login to UI
  3. launch orbital
  4. See page fault on terminal

Behavior

  • Expected behavior: I can use Ion
  • Actual behavior: Pagefault
Page fault: 0000000000000000
RFLAG: 0000000000010246
CS:    0000000000000023
RIP:   000000000056E16F
CODE:  0000000000000006
RAX:   0000028000001000
RCX:   0000028000001000
RDX:   0000000000000A30
RDI:   00000080000005C0
RSI:   00000080000005F0
R8:    8080808080808080
R9:    0000000200000000
R10:   0000000000000000
R11:   0000000000000065
RBX:   0000000000000000
RBP:   00000180000FFC40
R12:   0000000000000019
R13:   000000000000002E
R14:   00000080000005C0
R15:   00000000005F6BE8
FS:    0000000000000033
TRACE: FFFFFF40002017B0
  FFFFFF40002017B0: FFFFFF000019C6B5
    FFFFFF000019C610+00A5
    kernel::arch::x86_64::interrupt::exception::page::inner::h55eaa041bbf4716d
  FFFFFF4000201810: FFFFFF000019C60B
    FFFFFF000019C5E0+002B
    kernel::arch::x86_64::interrupt::exception::page::h7b475d05caa98e7d
  00000180000FFC40: 0000000000575E86
  00000180000FFD30: 0000000000575B52
  00000180000FFD70: 000000000056E30C
  00000180000FFDC0: 00000000005763F9
  00000180000FFE80: 00000000004001F5
 0000008000000018: EMPTY RETURN
SIGNAL 11, CPU 0, PID ContextId(42)
NAME file:/bin/ion
Kill 42 9
Send 9 to 42

Optional extras

We've been trying to get to the bottom of this on Mattermost and we found a few relevant pointers:

  • Has happened to multiple people
  • Happens on qemu and virtualbox
  • Happens in terminal and UI
  • Reverting ION as far back as august 6th doesn't help, still crashes
  • Reverting Kernel back to 1.3.2 doesn't help, still crashes
  • We tried gdb with breakpoint to kernel::syscall::process::exec and figured out that it crashes in file src/syscall/process.rs after:
821        unsafe { usermode(entry, sp, 0); }
(gdb) next

The backtrace is not very helpful, it seems:

(gdb) bt
#0  kernel::kmain (cpus=<optimized out>, env=...) at src/lib.rs:171
#1  kernel::arch::x86_64::start::kstart (args_ptr=<optimized out>) at src/arch/x86_64/start.rs:135

If I can be of any further help, let me know! Also it would probably be good if someone with a bit more redox knowledge tried reproducing my reverts, to make sure I didn't make a mistake while doing it.