Wmaybe-uninitialized with trivial auto var init

[xnox]

Description

Compiling criu with -Wall -Werror -ftrivial-auto-var-init=zero using gcc-14 spots an uninitialized variable in crui/tls

In

criu/criu/tls.c

Line 195 in e7aefe4

gnutls_packet_deinit(packet);

it is not certain that len will always be more than zero; thus it is possible to call this function with len set to zero and indeed packet is deinited without being allocated first

I have no idea why GCC's -ftrivial-auto-var-init=zero helps it find this Wmaybe-uninitialized, when such warning was already active.

Steps to reproduce the issue:

1. Build with cflags set to -ftrivial-auto-var-init=zero

Describe the results you received:

Build failure

Describe the results you expected:

Build passes

Additional information you deem important (e.g. issue happens only occasionally):

Asserting len, or checking len input value and exiting the function straight away should help the compiler here.