Re: [PATCH] fuzz: do not use POSIX shm for coverage bitmap

[Stefan Hajnoczi]

On Mon, Jun 22, 2020 at 12:50:40PM -0400, Alexander Bulekov wrote:
> We used shm_open with mmap to share libfuzzer's coverage bitmap with
> child (runner) processes. The same functionality can be achieved with
> MAP_SHARED | MAP_ANONYMOUS, since we do not care about naming or
> permissioning the shared memory object.
> 
> Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
> ---
> This might fix:
> qemu-fuzz-i386-target-virtio-net-socket: Unexpected-exit in
> counter_shm_init 
> https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=23636 (private link)
> 
> oss-fuzz does not provide access to /dev/, so it is likely that shm_open
> breaks, when it tries to access /dev/shm. This seems likely, based on
> the oss-fuzz minijail setup:
> https://github.com/google/oss-fuzz/blob/3740c751fd9edea138c17783995d370d6b1b89bc/infra/base-images/base-runner/run_minijail
> 
>  tests/qtest/fuzz/fork_fuzz.c | 40 ++++++++++++------------------------
>  1 file changed, 13 insertions(+), 27 deletions(-)

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

signature.asc
Description: PGP signature