qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Qemu-devel] [Bug 1724485] Re: Invalid assertion in arm_read_memory_func


From: Christophe Lyon
Subject: [Qemu-devel] [Bug 1724485] Re: Invalid assertion in arm_read_memory_func
Date: Wed, 18 Oct 2017 08:46:49 -0000

The tarball contains:
scoped1.exe
etc/ld.so.cache
lib/libm.so.6
lib/libstdc++.so.6
lib/lib.c.so.6
lib/ld-linux-armhf.so.3
lib/libgcc_s.so.1

I can reproduce the problem with qemu-2.10.1:
qemu-armeb -E LD_LIBRARY_PATH=$PWD/lib -cpu any -R 0 -d in_asm -L $PWD 
$PWD/scoped1.exe

Removing '-d in_asm' works OK, because the offending assert is triggered
while disassembling.

BTW, the program (scoped1.exe) does abort, it is a GCC testcase I was
trying to debug ;-)

Removing the assert lets execution continue, but the disassembly is incorrect. 
Without the assert, I see:
IN: strlen
0x40a1a880: f000 f890  bl 0x40a1a9a4
0x40a1a884: 4502       cmp r2, r0
but strlen normally starts with a pld instruction.

So probably print_insn_arm needs also a change like
given = (b[1]) | (b[0] <<8)<<16 | given;
instead of
given = (b[1]) | (b[0] <<8)|(given << 16);


** Attachment added: "qemu-bug-1724485.tar.xz"
   
https://bugs.launchpad.net/qemu/+bug/1724485/+attachment/4974653/+files/qemu-bug-1724485.tar.xz

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1724485

Title:
  Invalid assertion in arm_read_memory_func

Status in QEMU:
  New

Bug description:
  Hi,

  I think there is an invalid assertion in arm_read_memory_func:
  assert(info->endian == BFD_ENDIAN_LITTLE)

  I face it in the following use case: target armeb-linux (I use qemu
  user mode), -d in_asm -cpu any.

  At some point during program startup, glibc's _dl_new_object calls
  strlen, which is written in thumb2 mode (armv6t2). So print_insn_arm()
  calls arm_read_memory_func() with length==2, and info->flags ==
  INSN_ARM_BE32, and the assert is false.

  If I remove the assert, execution continues OK.

  With the assert, I get the error message from the assert, and qemu
  then stalls.

  Can you confirm the assert can be removed? Or if not, explain me how
  to avoid/fix the subsequent qemu stall?

  Thanks

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1724485/+subscriptions



reply via email to

[Prev in Thread] Current Thread [Next in Thread]