Re: [PATCH for-8.0 1/3] async: Suppress GCC13 false positive in aio_bh_poll()

[Stefan Hajnoczi]

On Tue, Mar 21, 2023 at 09:33:20AM +0100, Cédric Le Goater wrote:
> From: Cédric Le Goater <clg@redhat.com>
> 
> GCC13 reports an error :
> 
> ../util/async.c: In function ‘aio_bh_poll’:
> include/qemu/queue.h:303:22: error: storing the address of local variable 
> ‘slice’ in ‘*ctx.bh_slice_list.sqh_last’ [-Werror=dangling-pointer=]
>   303 |     (head)->sqh_last = &(elm)->field.sqe_next;                        
>   \
>       |     ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
> ../util/async.c:169:5: note: in expansion of macro ‘QSIMPLEQ_INSERT_TAIL’
>   169 |     QSIMPLEQ_INSERT_TAIL(&ctx->bh_slice_list, &slice, next);
>       |     ^~~~~~~~~~~~~~~~~~~~
> ../util/async.c:161:17: note: ‘slice’ declared here
>   161 |     BHListSlice slice;
>       |                 ^~~~~
> ../util/async.c:161:17: note: ‘ctx’ declared here
> 
> But the local variable 'slice' is removed from the global context list
> in following loop of the same routine. Add an intermediate helper to
> silent GCC. No functional change.
> 
> Cc: Stefan Hajnoczi <stefanha@redhat.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Daniel P. Berrangé <berrange@redhat.com>
> Signed-off-by: Cédric Le Goater <clg@redhat.com>
> ---
>  util/async.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)

Thanks!

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

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