fuzz: remove fork-fuzzing scaffolding

Fork-fuzzing provides a few pros, but our implementation prevents us
from using fuzzers other than libFuzzer, and may be causing issues such
as coverage-failure builds on OSS-Fuzz. It is not a great long-term
solution as it depends on internal implementation details of libFuzzer
(which is no longer in active development). Remove it in favor of other
methods of resetting state between inputs.

Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>

meson.build

@@ -215,10 +215,6 @@ endif
 # Specify linker-script with add_project_link_arguments so that it is not placed
 # within a linker --start-group/--end-group pair
 if get_option('fuzzing')
-  add_project_link_arguments(['-Wl,-T,',
-                              (meson.current_source_dir() / 'tests/qtest/fuzz/fork_fuzz.ld')],
-                             native: false, language: all_languages)
-
   # Specify a filter to only instrument code that is directly related to
   # virtual-devices.
   configure_file(output: 'instrumentation-filter',

tests/qtest/fuzz/meson.build

@@ -2,7 +2,7 @@ if not get_option('fuzzing')
   subdir_done()
 endif
 
-specific_fuzz_ss.add(files('fuzz.c', 'fork_fuzz.c', 'qos_fuzz.c',
+specific_fuzz_ss.add(files('fuzz.c', 'qos_fuzz.c',
                            'qtest_wrappers.c'), qos)
 
 # Targets
@@ -12,7 +12,7 @@ specific_fuzz_ss.add(when: 'CONFIG_VIRTIO_SCSI', if_true: files('virtio_scsi_fuz
 specific_fuzz_ss.add(when: 'CONFIG_VIRTIO_BLK', if_true: files('virtio_blk_fuzz.c'))
 specific_fuzz_ss.add(files('generic_fuzz.c'))
 
-fork_fuzz = declare_dependency(
+fuzz_ld = declare_dependency(
   link_args: fuzz_exe_ldflags +
              ['-Wl,-wrap,qtest_inb',
               '-Wl,-wrap,qtest_inw',
@@ -35,4 +35,4 @@ fork_fuzz = declare_dependency(
               '-Wl,-wrap,qtest_memset']
 )
 
-specific_fuzz_ss.add(fork_fuzz)
+specific_fuzz_ss.add(fuzz_ld)