[Qemu-devel] [Bug 1426593] [NEW] qem-user arm cortex-a8 printf out-of-memory hang

[Qemu-devel] [Bug 1426593] [NEW] qem-user arm cortex-a8 printf out-of-memory hang

[aaron]

Public bug reported:

using the latest build from git (hash 041ccc922ee474693a2869d4e3b59e920c739bc0 ) and all older versions i have tested.
i am using an amd64 host with an arm chroot using "qemu-user arm cortex-a8" cpu emulation to run it

building coreutils hangs on "checking whether printf survives out-of-
memory conditions"

i have not had time to dig into the build system to isolate the test
yet, there were old reports of this bug but i can no longer find them on
google.

** Affects: qemu
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1426593

Title:
  qem-user arm cortex-a8 printf out-of-memory hang

Status in QEMU:
  New

Bug description:
  using the latest build from git (hash 041ccc922ee474693a2869d4e3b59e920c739bc0 ) and all older versions i have tested.
  i am using an amd64 host with an arm chroot using "qemu-user arm cortex-a8" cpu emulation to run it

  building coreutils hangs on "checking whether printf survives out-of-
  memory conditions"

  i have not had time to dig into the build system to isolate the test
  yet, there were old reports of this bug but i can no longer find them
  on google.

To manage notifications about this bug go to:
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Re: [Qemu-devel] [Bug 1426593] [NEW] qem-user arm cortex-a8 printf out-of-memory hang

[Peter Maydell]

On 28 February 2015 at 09:01, aaron <chainsawbike@gmail.com> wrote:
> Public bug reported:
>
> using the latest build from git (hash 041ccc922ee474693a2869d4e3b59e920c739bc0 ) and all older versions i have tested.
> i am using an amd64 host with an arm chroot using "qemu-user arm cortex-a8" cpu emulation to run it
>
> building coreutils hangs on "checking whether printf survives out-of-
> memory conditions"
>
> i have not had time to dig into the build system to isolate the test
> yet, there were old reports of this bug but i can no longer find them on
> google.

Yes, I seem to recall looking at this one before. QEMU's linux-user
code doesn't try to isolate the guest's memory allocations from
its own allocations. So if the guest sets the memory limit to
something very small then the chances are good that this will
result in one of QEMU's internal allocations failing, and then
QEMU will probably exit with an error or possibly crash or hang
(some of our error handling on these allocations is not good).

For this kind of test to work correctly we would need to fake
the memory limit syscalls rather than just passing them through
to the host, and then also do all the accounting to track how
much memory the guest has allocated. That's a fair amount of
work so it's unlikely this bug will be fixed unless somebody
who cares about it submits patches, I'm afraid.

-- PMM

[Qemu-devel] [Bug 1426593] Re: qem-user arm cortex-a8 printf out-of-memory hang

[Peter Maydell]

** Tags added: linux-user

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

** Summary changed:

- qem-user arm cortex-a8 printf out-of-memory hang
+ linux-user: doesn't handle guest setting its memory ulimit very small

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You received this bug notification because you are a member of qemu-
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https://bugs.launchpad.net/bugs/1426593

Title:
  linux-user: doesn't handle guest setting its memory ulimit very small

Status in QEMU:
  Confirmed

Bug description:
  using the latest build from git (hash 041ccc922ee474693a2869d4e3b59e920c739bc0 ) and all older versions i have tested.
  i am using an amd64 host with an arm chroot using "qemu-user arm cortex-a8" cpu emulation to run it

  building coreutils hangs on "checking whether printf survives out-of-
  memory conditions"

  i have not had time to dig into the build system to isolate the test
  yet, there were old reports of this bug but i can no longer find them
  on google.

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1426593/+subscriptions

[Qemu-devel] [Bug 1426593] Re: linux-user: doesn't handle guest setting its memory ulimit very small

[Peter Maydell]

*** This bug is a duplicate of bug 1163034 ***
    https://bugs.launchpad.net/bugs/1163034

I've just noticed that this is a duplicate of bug 1163034 (gnutls uses a
very similar configure test), so I'm going to mark this one as a dup of
that one, since it's older.


** This bug has been marked a duplicate of bug 1163034
   linux-user mode can't handle guest setting RLIMIT_AS (hangs running gnutls28 configure check code)

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1426593

Title:
  linux-user: doesn't handle guest setting its memory ulimit very small

Status in QEMU:
  Confirmed

Bug description:
  using the latest build from git (hash 041ccc922ee474693a2869d4e3b59e920c739bc0 ) and all older versions i have tested.
  i am using an amd64 host with an arm chroot using "qemu-user arm cortex-a8" cpu emulation to run it

  building coreutils hangs on "checking whether printf survives out-of-
  memory conditions"

  i have not had time to dig into the build system to isolate the test
  yet, there were old reports of this bug but i can no longer find them
  on google.

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1426593/+subscriptions