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* [Bug 1914021] [NEW] qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-debug exited normally
@ 2021-02-01  9:06 Dong JianQiang
  2021-02-01  9:48 ` [Bug 1914021] " Peter Maydell
                   ` (6 more replies)
  0 siblings, 7 replies; 8+ messages in thread
From: Dong JianQiang @ 2021-02-01  9:06 UTC (permalink / raw)
  To: qemu-devel

Public bug reported:

I'm getting Illegal instruction (core dumped) when running the attached
a.out_err binary in qemu, but when using Gdb to remote-debug the
program, it exited normally. will appreciate if you can help look into
this qemu issue.

readelf -h a.out_err
ELF Header:
  Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
  Class:                             ELF32
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              EXEC (Executable file)
  Machine:                           ARM
  Version:                           0x1
  Entry point address:               0x8220
  Start of program headers:          52 (bytes into file)
  Start of section headers:          54228 (bytes into file)
  Flags:                             0x5000200, Version5 EABI, soft-float ABI
  Size of this header:               52 (bytes)
  Size of program headers:           32 (bytes)
  Number of program headers:         3
  Size of section headers:           40 (bytes)
  Number of section headers:         16
  Section header string table index: 15

qemu-arm version 4.0.0

** Affects: qemu
     Importance: Undecided
         Status: New

** Attachment added: "a.out_err"
   https://bugs.launchpad.net/bugs/1914021/+attachment/5458737/+files/a.out_err

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1914021

Title:
  qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-
  debug exited normally

Status in QEMU:
  New

Bug description:
  I'm getting Illegal instruction (core dumped) when running the
  attached a.out_err binary in qemu, but when using Gdb to remote-debug
  the program, it exited normally. will appreciate if you can help look
  into this qemu issue.

  readelf -h a.out_err
  ELF Header:
    Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
    Class:                             ELF32
    Data:                              2's complement, little endian
    Version:                           1 (current)
    OS/ABI:                            UNIX - System V
    ABI Version:                       0
    Type:                              EXEC (Executable file)
    Machine:                           ARM
    Version:                           0x1
    Entry point address:               0x8220
    Start of program headers:          52 (bytes into file)
    Start of section headers:          54228 (bytes into file)
    Flags:                             0x5000200, Version5 EABI, soft-float ABI
    Size of this header:               52 (bytes)
    Size of program headers:           32 (bytes)
    Number of program headers:         3
    Size of section headers:           40 (bytes)
    Number of section headers:         16
    Section header string table index: 15

  qemu-arm version 4.0.0

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1914021/+subscriptions


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [Bug 1914021] Re: qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-debug exited normally
  2021-02-01  9:06 [Bug 1914021] [NEW] qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-debug exited normally Dong JianQiang
@ 2021-02-01  9:48 ` Peter Maydell
  2021-02-01 10:42 ` Dong JianQiang
                   ` (5 subsequent siblings)
  6 siblings, 0 replies; 8+ messages in thread
From: Peter Maydell @ 2021-02-01  9:48 UTC (permalink / raw)
  To: qemu-devel

QEMU 4.0 is quite old now -- does this reproduce with a more recent
QEMU?

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1914021

Title:
  qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-
  debug exited normally

Status in QEMU:
  New

Bug description:
  I'm getting Illegal instruction (core dumped) when running the
  attached a.out_err binary in qemu, but when using Gdb to remote-debug
  the program, it exited normally. will appreciate if you can help look
  into this qemu issue.

  readelf -h a.out_err
  ELF Header:
    Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
    Class:                             ELF32
    Data:                              2's complement, little endian
    Version:                           1 (current)
    OS/ABI:                            UNIX - System V
    ABI Version:                       0
    Type:                              EXEC (Executable file)
    Machine:                           ARM
    Version:                           0x1
    Entry point address:               0x8220
    Start of program headers:          52 (bytes into file)
    Start of section headers:          54228 (bytes into file)
    Flags:                             0x5000200, Version5 EABI, soft-float ABI
    Size of this header:               52 (bytes)
    Size of program headers:           32 (bytes)
    Number of program headers:         3
    Size of section headers:           40 (bytes)
    Number of section headers:         16
    Section header string table index: 15

  qemu-arm version 4.0.0

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1914021/+subscriptions


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [Bug 1914021] Re: qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-debug exited normally
  2021-02-01  9:06 [Bug 1914021] [NEW] qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-debug exited normally Dong JianQiang
  2021-02-01  9:48 ` [Bug 1914021] " Peter Maydell
@ 2021-02-01 10:42 ` Dong JianQiang
  2021-02-01 11:05 ` Peter Maydell
                   ` (4 subsequent siblings)
  6 siblings, 0 replies; 8+ messages in thread
From: Dong JianQiang @ 2021-02-01 10:42 UTC (permalink / raw)
  To: qemu-devel

yes, it reproduced on QEMU 5.0.0.

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1914021

Title:
  qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-
  debug exited normally

Status in QEMU:
  New

Bug description:
  I'm getting Illegal instruction (core dumped) when running the
  attached a.out_err binary in qemu, but when using Gdb to remote-debug
  the program, it exited normally. will appreciate if you can help look
  into this qemu issue.

  readelf -h a.out_err
  ELF Header:
    Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
    Class:                             ELF32
    Data:                              2's complement, little endian
    Version:                           1 (current)
    OS/ABI:                            UNIX - System V
    ABI Version:                       0
    Type:                              EXEC (Executable file)
    Machine:                           ARM
    Version:                           0x1
    Entry point address:               0x8220
    Start of program headers:          52 (bytes into file)
    Start of section headers:          54228 (bytes into file)
    Flags:                             0x5000200, Version5 EABI, soft-float ABI
    Size of this header:               52 (bytes)
    Size of program headers:           32 (bytes)
    Number of program headers:         3
    Size of section headers:           40 (bytes)
    Number of section headers:         16
    Section header string table index: 15

  qemu-arm version 4.0.0

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1914021/+subscriptions


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [Bug 1914021] Re: qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-debug exited normally
  2021-02-01  9:06 [Bug 1914021] [NEW] qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-debug exited normally Dong JianQiang
  2021-02-01  9:48 ` [Bug 1914021] " Peter Maydell
  2021-02-01 10:42 ` Dong JianQiang
@ 2021-02-01 11:05 ` Peter Maydell
  2021-02-01 13:06 ` Dong JianQiang
                   ` (3 subsequent siblings)
  6 siblings, 0 replies; 8+ messages in thread
From: Peter Maydell @ 2021-02-01 11:05 UTC (permalink / raw)
  To: qemu-devel

For me, with current head-of-git QEMU, the program crashes with a
SIGSEGV very early in execution, because:

0x00008260:  e59f30f0  ldr      r3, [pc, #0xf0]

loads 0 into r3, and then

0x00008270:  e1a0d003  mov      sp, r3

sets sp to 0, and then

0x000087b0:  e92d4030  push     {r4, r5, lr}

tries to write to addres 0, which causes a SEGV.

This happens whether using the gdbstub or not.

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1914021

Title:
  qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-
  debug exited normally

Status in QEMU:
  New

Bug description:
  I'm getting Illegal instruction (core dumped) when running the
  attached a.out_err binary in qemu, but when using Gdb to remote-debug
  the program, it exited normally. will appreciate if you can help look
  into this qemu issue.

  readelf -h a.out_err
  ELF Header:
    Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
    Class:                             ELF32
    Data:                              2's complement, little endian
    Version:                           1 (current)
    OS/ABI:                            UNIX - System V
    ABI Version:                       0
    Type:                              EXEC (Executable file)
    Machine:                           ARM
    Version:                           0x1
    Entry point address:               0x8220
    Start of program headers:          52 (bytes into file)
    Start of section headers:          54228 (bytes into file)
    Flags:                             0x5000200, Version5 EABI, soft-float ABI
    Size of this header:               52 (bytes)
    Size of program headers:           32 (bytes)
    Number of program headers:         3
    Size of section headers:           40 (bytes)
    Number of section headers:         16
    Section header string table index: 15

  qemu-arm version 4.0.0

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1914021/+subscriptions


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [Bug 1914021] Re: qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-debug exited normally
  2021-02-01  9:06 [Bug 1914021] [NEW] qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-debug exited normally Dong JianQiang
                   ` (2 preceding siblings ...)
  2021-02-01 11:05 ` Peter Maydell
@ 2021-02-01 13:06 ` Dong JianQiang
  2021-02-01 13:54 ` Peter Maydell
                   ` (2 subsequent siblings)
  6 siblings, 0 replies; 8+ messages in thread
From: Dong JianQiang @ 2021-02-01 13:06 UTC (permalink / raw)
  To: qemu-devel

0x00008260 <+64>:    ldr     r3, [pc, #240]
   0x00008264 <+68>:    cmp     r1, #0
=> 0x00008268 <+72>:    beq     0x8270
   0x0000826c <+76>:    mov     r3, r1
   0x00008270 <+80>:    mov     sp, r3

(gdb) p/x $r1
$2 = 0xfffef690

But r1 is not zero when using Gdb remote-debug, so it will enter 
   0x0000826c <+76>:    mov     r3, r1

QEMU 5.0.0.
GNU gdb (GDB; SUSE Linux Enterprise 12) 8.0.1

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1914021

Title:
  qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-
  debug exited normally

Status in QEMU:
  New

Bug description:
  I'm getting Illegal instruction (core dumped) when running the
  attached a.out_err binary in qemu, but when using Gdb to remote-debug
  the program, it exited normally. will appreciate if you can help look
  into this qemu issue.

  readelf -h a.out_err
  ELF Header:
    Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
    Class:                             ELF32
    Data:                              2's complement, little endian
    Version:                           1 (current)
    OS/ABI:                            UNIX - System V
    ABI Version:                       0
    Type:                              EXEC (Executable file)
    Machine:                           ARM
    Version:                           0x1
    Entry point address:               0x8220
    Start of program headers:          52 (bytes into file)
    Start of section headers:          54228 (bytes into file)
    Flags:                             0x5000200, Version5 EABI, soft-float ABI
    Size of this header:               52 (bytes)
    Size of program headers:           32 (bytes)
    Number of program headers:         3
    Size of section headers:           40 (bytes)
    Number of section headers:         16
    Section header string table index: 15

  qemu-arm version 4.0.0

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1914021/+subscriptions


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [Bug 1914021] Re: qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-debug exited normally
  2021-02-01  9:06 [Bug 1914021] [NEW] qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-debug exited normally Dong JianQiang
                   ` (3 preceding siblings ...)
  2021-02-01 13:06 ` Dong JianQiang
@ 2021-02-01 13:54 ` Peter Maydell
  2021-05-12 18:02 ` Thomas Huth
  2021-07-12  4:17 ` Launchpad Bug Tracker
  6 siblings, 0 replies; 8+ messages in thread
From: Peter Maydell @ 2021-02-01 13:54 UTC (permalink / raw)
  To: qemu-devel

Oh, your code is trying to use the SYS_HEAPINFO semihosting call to
figure out where the stack and heap are. This is generally a bad idea if
you're using QEMU user-mode emulation: you start with a perfectly good
stack pointer and you should just use the usual Linux syscalls to
allocate heap if you need it.

I have no idea where your code is getting r1 from -- it's too painful to
try to reverse-engineer it from the binary. I can't repro any difference
between with-gdb and without -- for me with current QEMU r1 is 0 whether
running with the gdb stub or not.

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1914021

Title:
  qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-
  debug exited normally

Status in QEMU:
  New

Bug description:
  I'm getting Illegal instruction (core dumped) when running the
  attached a.out_err binary in qemu, but when using Gdb to remote-debug
  the program, it exited normally. will appreciate if you can help look
  into this qemu issue.

  readelf -h a.out_err
  ELF Header:
    Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
    Class:                             ELF32
    Data:                              2's complement, little endian
    Version:                           1 (current)
    OS/ABI:                            UNIX - System V
    ABI Version:                       0
    Type:                              EXEC (Executable file)
    Machine:                           ARM
    Version:                           0x1
    Entry point address:               0x8220
    Start of program headers:          52 (bytes into file)
    Start of section headers:          54228 (bytes into file)
    Flags:                             0x5000200, Version5 EABI, soft-float ABI
    Size of this header:               52 (bytes)
    Size of program headers:           32 (bytes)
    Number of program headers:         3
    Size of section headers:           40 (bytes)
    Number of section headers:         16
    Section header string table index: 15

  qemu-arm version 4.0.0

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1914021/+subscriptions


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [Bug 1914021] Re: qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-debug exited normally
  2021-02-01  9:06 [Bug 1914021] [NEW] qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-debug exited normally Dong JianQiang
                   ` (4 preceding siblings ...)
  2021-02-01 13:54 ` Peter Maydell
@ 2021-05-12 18:02 ` Thomas Huth
  2021-07-12  4:17 ` Launchpad Bug Tracker
  6 siblings, 0 replies; 8+ messages in thread
From: Thomas Huth @ 2021-05-12 18:02 UTC (permalink / raw)
  To: qemu-devel

The QEMU project is currently moving its bug tracking to another system.
For this we need to know which bugs are still valid and which could be
closed already. Thus we are setting the bug state to "Incomplete" now.

If the bug has already been fixed in the latest upstream version of QEMU,
then please close this ticket as "Fix released".

If it is not fixed yet and you think that this bug report here is still
valid, then you have two options:

1) If you already have an account on gitlab.com, please open a new ticket
for this problem in our new tracker here:

    https://gitlab.com/qemu-project/qemu/-/issues

and then close this ticket here on Launchpad (or let it expire auto-
matically after 60 days). Please mention the URL of this bug ticket on
Launchpad in the new ticket on GitLab.

2) If you don't have an account on gitlab.com and don't intend to get
one, but still would like to keep this ticket opened, then please switch
the state back to "New" or "Confirmed" within the next 60 days (other-
wise it will get closed as "Expired"). We will then eventually migrate
the ticket automatically to the new system (but you won't be the reporter
of the bug in the new system and thus you won't get notified on changes
anymore).

Thank you and sorry for the inconvenience.


** Changed in: qemu
       Status: New => Incomplete

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1914021

Title:
  qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-
  debug exited normally

Status in QEMU:
  Incomplete

Bug description:
  I'm getting Illegal instruction (core dumped) when running the
  attached a.out_err binary in qemu, but when using Gdb to remote-debug
  the program, it exited normally. will appreciate if you can help look
  into this qemu issue.

  readelf -h a.out_err
  ELF Header:
    Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
    Class:                             ELF32
    Data:                              2's complement, little endian
    Version:                           1 (current)
    OS/ABI:                            UNIX - System V
    ABI Version:                       0
    Type:                              EXEC (Executable file)
    Machine:                           ARM
    Version:                           0x1
    Entry point address:               0x8220
    Start of program headers:          52 (bytes into file)
    Start of section headers:          54228 (bytes into file)
    Flags:                             0x5000200, Version5 EABI, soft-float ABI
    Size of this header:               52 (bytes)
    Size of program headers:           32 (bytes)
    Number of program headers:         3
    Size of section headers:           40 (bytes)
    Number of section headers:         16
    Section header string table index: 15

  qemu-arm version 4.0.0

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1914021/+subscriptions


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [Bug 1914021] Re: qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-debug exited normally
  2021-02-01  9:06 [Bug 1914021] [NEW] qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-debug exited normally Dong JianQiang
                   ` (5 preceding siblings ...)
  2021-05-12 18:02 ` Thomas Huth
@ 2021-07-12  4:17 ` Launchpad Bug Tracker
  6 siblings, 0 replies; 8+ messages in thread
From: Launchpad Bug Tracker @ 2021-07-12  4:17 UTC (permalink / raw)
  To: qemu-devel

[Expired for QEMU because there has been no activity for 60 days.]

** Changed in: qemu
       Status: Incomplete => Expired

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1914021

Title:
  qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-
  debug exited normally

Status in QEMU:
  Expired

Bug description:
  I'm getting Illegal instruction (core dumped) when running the
  attached a.out_err binary in qemu, but when using Gdb to remote-debug
  the program, it exited normally. will appreciate if you can help look
  into this qemu issue.

  readelf -h a.out_err
  ELF Header:
    Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
    Class:                             ELF32
    Data:                              2's complement, little endian
    Version:                           1 (current)
    OS/ABI:                            UNIX - System V
    ABI Version:                       0
    Type:                              EXEC (Executable file)
    Machine:                           ARM
    Version:                           0x1
    Entry point address:               0x8220
    Start of program headers:          52 (bytes into file)
    Start of section headers:          54228 (bytes into file)
    Flags:                             0x5000200, Version5 EABI, soft-float ABI
    Size of this header:               52 (bytes)
    Size of program headers:           32 (bytes)
    Number of program headers:         3
    Size of section headers:           40 (bytes)
    Number of section headers:         16
    Section header string table index: 15

  qemu-arm version 4.0.0

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1914021/+subscriptions


^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2021-07-12  4:27 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-02-01  9:06 [Bug 1914021] [NEW] qemu: uncaught target signal 4 (Illegal instruction) but gdb remote-debug exited normally Dong JianQiang
2021-02-01  9:48 ` [Bug 1914021] " Peter Maydell
2021-02-01 10:42 ` Dong JianQiang
2021-02-01 11:05 ` Peter Maydell
2021-02-01 13:06 ` Dong JianQiang
2021-02-01 13:54 ` Peter Maydell
2021-05-12 18:02 ` Thomas Huth
2021-07-12  4:17 ` Launchpad Bug Tracker

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