Re: [PATCH 2/3] bsd-user/mmap: use TSA_NO_TSA to suppress clang TSA warnings

[Stefan Hajnoczi <stefanha@redhat.com>]

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On Tue, Jan 17, 2023 at 08:52:02AM -0500, Emanuele Giuseppe Esposito wrote:
> QEMU does not compile when enabling clang's thread safety analysis
> (TSA),
> because some functions create wrappers for pthread mutexes but do
> not use any TSA macro. Therefore the compiler fails.
> 
> In order to make the compiler happy and avoid adding all the
> necessary macros to all callers (lock functions should use
> TSA_ACQUIRE, while unlock TSA_RELEASE, and this applies to allusers of pthread_mutex_lock/pthread_mutex_unlock),
> simply use TSA_NO_TSA to supppress such warnings.
> 
> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
> ---
>  bsd-user/qemu.h         | 5 +++--
>  include/exec/exec-all.h | 5 +++--
>  2 files changed, 6 insertions(+), 4 deletions(-)

As a TSA newbie I'm wondering how would we go about annotating this
properly?

Maybe:
1. mmap_lock() ACQUIRE(), mmap_unlock() RELEASE()
2. Find all functions that call mmap_lock() but not mmap_release() and
   add ACQUIRE().
3. Find all functions that call mmap_unlock() but not mmap_lock() and
   add RELEASE().

Can you add an item to https://wiki.qemu.org/BiteSizedTasks so someone
who wants to spend a few hours auditing the code can do this?

Thanks!

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