[Qemu-devel] [Bug 1727737] Re: qemu-arm stalls on a GCC sanitizer test since qemu-2.7

[Peter Maydell]

Hmm, the do_fork() code is a bit inconsistent there. Generally in linux-user/ 
functions should either:
(1) return -1 with host errno set to a host errno; the caller then must use 
get_errno() to convert to the negative-target-errno that we need to return from 
do_syscall()
(2) return negative-target-errno; the caller then need do nothing

In this case do_fork() is supposed to be using approach 2, but some code
paths are using approach 1 and the callers are all using get_errno().
This hybrid approach works OK as long as none of the negative-target-
errno values returned are -1 (which happens to be TARGET_EPERM for all
architectures, and which we only use once in linux-user, in the
sigaltstack handling). In an ideal world we'd clean this up to
consistently use approach 2, but I don't think the code as it stands is
actually buggy.

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1727737

Title:
  qemu-arm stalls on a GCC sanitizer test since qemu-2.7

Status in QEMU:
  Incomplete

Bug description:
  Hi,

  I have noticed that several GCC/sanitizer tests fail with timeout when
  executed under QEMU.

  After a bit of investigation, I have noticed that this worked with
  qemu-2.7, and started failing with qemu-2.8, and still fails with
  qemu-2.10.1

  I'm attaching a tarball containing:
  alloca_instruments_all_paddings.exe : the testcase, and the needed libs:
  lib/librt.so.1
  lib/libdl.so.2
  lib/ld-linux-armhf.so.3
  lib/libasan.so.5
  lib/libc.so.6
  lib/libgcc_s.so.1
  lib/libpthread.so.0
  lib/libm.so.6

  To reproduce the problem:
  $ qemu-arm -cpu any -R 0 -L $PWD $PWD/alloca_instruments_all_paddings.exe
  returns in less than a second with qemu-2.7, and never with qemu-2.8

  Using -d in_asm suggests that the program "almost" completes and qemu seems 
to stall on:
  0x40b6eb44: e08f4004 add r4, pc, r4

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1727737/+subscriptions