Re: [PATCH-for-6.1] softmmu/physmem: fix wrong assertion in qemu_ram_alloc_internal()

[Philippe Mathieu-Daudé]

6.1 material btw.

On 8/2/21 5:26 PM, Philippe Mathieu-Daudé wrote:
> On 8/2/21 5:22 PM, David Hildenbrand wrote:
>> When adding RAM_NORESERVE, we forgot to remove the old assertion when
>> adding the updated one, most probably when reworking the patches or
>> rebasing. We can easily crash QEMU by adding
>>   -object memory-backend-ram,id=mem0,size=500G,reserve=off
>> to the QEMU cmdline:
>>   qemu-system-x86_64: ../softmmu/physmem.c:2146: qemu_ram_alloc_internal:
>>   Assertion `(ram_flags & ~(RAM_SHARED | RAM_RESIZEABLE | RAM_PREALLOC))
>>   == 0' failed.
> 
> Oops.
> 
>> Fix it by removing the old assertion.
>>
>> Fixes: 8dbe22c6868b ("memory: Introduce RAM_NORESERVE and wire it up in 
>> qemu_ram_mmap()")
>> Cc: Paolo Bonzini <pbonzini@redhat.com>
>> Cc: Peter Xu <peterx@redhat.com>
>> Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
>> Signed-off-by: David Hildenbrand <david@redhat.com>
> 
> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> 
>> ---
>>  softmmu/physmem.c | 1 -
>>  1 file changed, 1 deletion(-)
>>
>> diff --git a/softmmu/physmem.c b/softmmu/physmem.c
>> index 3c1912a1a0..2e18947598 100644
>> --- a/softmmu/physmem.c
>> +++ b/softmmu/physmem.c
>> @@ -2143,7 +2143,6 @@ RAMBlock *qemu_ram_alloc_internal(ram_addr_t size, 
>> ram_addr_t max_size,
>>      RAMBlock *new_block;
>>      Error *local_err = NULL;
>>  
>> -    assert((ram_flags & ~(RAM_SHARED | RAM_RESIZEABLE | RAM_PREALLOC)) == 
>> 0);
>>      assert((ram_flags & ~(RAM_SHARED | RAM_RESIZEABLE | RAM_PREALLOC |
>>                            RAM_NORESERVE)) == 0);
>>      assert(!host ^ (ram_flags & RAM_PREALLOC));
>>
>