On Mon, May 11, 2026 at 02:47:38PM +0200, David Hildenbrand (Arm) wrote: > On 5/11/26 11:34, Hu Song wrote: > > From: Song Hu <[email protected]> > > > > When fork() fails and returns -1, the code falls into the else branch > > and stores -1 into self->pids[i]. Later, kill(-1, SIGTERM) is called > > which sends SIGTERM to every process the user has permission to signal, > > potentially killing the entire user session. > > > > Add an explicit check for fork() returning -1 (pid < 0). On failure, > > clean up any already-forked children before failing the test via > > ASSERT_GE(pid, 0). This fix is applied to all three fork() call sites > > in shared_anon, shared_anon_thp, and shared_anon_htlb tests. > > > > Signed-off-by: Hu Song <[email protected]> > > --- > > tools/testing/selftests/mm/migration.c | 15 +++++++++++++++ > > 1 file changed, 15 insertions(+) > > > > diff --git a/tools/testing/selftests/mm/migration.c > > b/tools/testing/selftests/mm/migration.c > > index 60e78bbfc0e3..f433e4f195ad 100644 > > --- a/tools/testing/selftests/mm/migration.c > > +++ b/tools/testing/selftests/mm/migration.c > > @@ -163,6 +163,11 @@ TEST_F_TIMEOUT(migration, shared_anon, 2*RUNTIME) > > memset(ptr, 0xde, TWOMEG); > > for (i = 0; i < self->nthreads - 1; i++) { > > pid = fork(); > > + if (pid < 0) { > > + while (--i >= 0) > > + kill(self->pids[i], SIGTERM); > > > > > + ASSERT_GE(pid, 0); > > + } > > if (!pid) { > > I think "else if" reads nicer here. > > But why do we care about cleaning up the other processes? IIUC, we don't do > that > explicitly if e.g., > > ASSERT_EQ(migrate(ptr, self->n1, self->n2), 0); > > fails?
We care about cleaning up all the forked processes because otherwise they remain zombies :) But killing some of them if a fork() failed does not help. I have a more structured fix here: https://lore.kernel.org/all/[email protected] > > -- > Cheers, > > David -- Sincerely yours, Mike.
