Re: [Qemu-devel] [PATCH] oslib: make error handling more reasonable

[Eric Blake <eblake@redhat.com>]

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On 02/10/2012 07:41 AM, Daniel P. Berrange wrote:

>> @@ -80,7 +80,7 @@ void *qemu_oom_check(void *ptr)
>>  {
>>      if (ptr == NULL) {
>>          fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno));
>> -        abort();
>> +        exit(EXIT_FAILURE);
> 
> exit() will call any atexit()/on_exit() handlers, as well as trying
> to flush I/O streams. Any of these actions may require further
> memory allocations, which will likely fail, or worse cause this
> code to re-enter itself if an atexit() handler calls qemu_malloc
> 
> The only option other than abort(), is to use  _Exit() which
> doesn't try to run cleanup handlers.

Correct, but in that case, then you need to fflush(stderr) prior to
_Exit(), or else use write() rather than fprintf(), since otherwise your
attempt at a nice oom error message is lost.

-- 
Eric Blake   eblake@redhat.com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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