passt/test/valgrind.supp
David Gibson f7724647b1 valgrind: Adjust suppression for MSG_TRUNC with NULL buffer
valgrind complains if we pass a NULL buffer to recv(), even if we use
MSG_TRUNC, in which case it's actually safe.  For a long time we've had
a valgrind suppression for this.  It singles out the recv() in
tcp_sock_consume(), the only place we use MSG_TRUNC.

However, tcp_sock_consume() only has a single caller, which makes it a
prime candidate for inlining.  If inlined, it won't appear on the stack and
valgrind won't match the correct suppression.

It appears that certain compiler versions (for example gcc-13.2.1 in
Fedora 39) will inline this function even with the -O0 we use for valgrind
builds.  This breaks the suppression leading to a spurious failure in the
tests.

There's not really any way to adjust the suppression itself without making
it overly broad (we don't want to match other recv() calls).  So, as a hack
explicitly prevent inlining of this function when we're making a valgrind
build.  To accomplish this add an explicit -DVALGRIND when making such a
build.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2023-11-19 09:10:12 +01:00

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# tcp_sock_consume() calls recv() with MSG_TRUNC and no buffer to discard data
{
passt_recv_MSG_TRUNC_into_NULL_buffer
Memcheck:Param
socketcall.recvfrom(buf)
...
fun:tcp_sock_consume
}