* SeongJae Park <s...@kernel.org> [240903 20:45]: > damon_test_three_regions_in_vmas() initializes a maple tree with > MM_MT_FLAGS. The flags contains MT_FLAGS_LOCK_EXTERN, which means > mt_lock of the maple tree will not be used. And therefore the maple > tree initialization code skips initialization of the mt_lock. However, > __link_vmas(), which adds vmas for test to the maple tree, uses the > mt_lock. In other words, the uninitialized spinlock is used. The > problem becomes celar when spinlock debugging is turned on, since it > reports spinlock bad magic bug. Fix the issue by not using the mt_lock > as promised.
You can't do this, lockdep will tell you this is wrong. We need a lock and to use the lock for writes. I'd suggest using different flags so the spinlock is used. > > Reported-by: Guenter Roeck <li...@roeck-us.net> > Closes: > https://lore.kernel.org/1453b2b2-6119-4082-ad9e-f3c5239bf...@roeck-us.net > Fixes: d0cf3dd47f0d ("damon: convert __damon_va_three_regions to use the VMA > iterator") > Signed-off-by: SeongJae Park <s...@kernel.org> > --- > mm/damon/tests/vaddr-kunit.h | 10 +++------- > 1 file changed, 3 insertions(+), 7 deletions(-) > > diff --git a/mm/damon/tests/vaddr-kunit.h b/mm/damon/tests/vaddr-kunit.h > index 83626483f82b..c6c7e0e0ab07 100644 > --- a/mm/damon/tests/vaddr-kunit.h > +++ b/mm/damon/tests/vaddr-kunit.h > @@ -17,23 +17,19 @@ > static int __link_vmas(struct maple_tree *mt, struct vm_area_struct *vmas, > ssize_t nr_vmas) > { > - int i, ret = -ENOMEM; > + int i; > MA_STATE(mas, mt, 0, 0); > > if (!nr_vmas) > return 0; > > - mas_lock(&mas); > for (i = 0; i < nr_vmas; i++) { > mas_set_range(&mas, vmas[i].vm_start, vmas[i].vm_end - 1); > if (mas_store_gfp(&mas, &vmas[i], GFP_KERNEL)) > - goto failed; > + return -ENOMEM; > } > > - ret = 0; > -failed: > - mas_unlock(&mas); > - return ret; > + return 0; > } > > /* > -- > 2.39.2 >
