On Thu, Jul 24, 2025 at 07:14:58PM +0800, Zhang Yi wrote: > On 2025/7/24 12:54, Theodore Ts'o wrote: > > On Wed, Jul 23, 2025 at 08:55:14PM -0700, Guenter Roeck wrote: > >> Hi, > >> > >> On Mon, Jul 14, 2025 at 09:03:25PM +0800, Baokun Li wrote: > >>> While traversing the list, holding a spin_lock prevents load_buddy, making > >>> direct use of ext4_try_lock_group impossible. This can lead to a bouncing > >>> scenario where spin_is_locked(grp_A) succeeds, but ext4_try_lock_group() > >>> fails, forcing the list traversal to repeatedly restart from grp_A. > >>> > >> > >> This patch causes crashes for pretty much every architecture when > >> running unit tests as part of booting. > > > > I'm assuming that you're using a randconfig that happened to enable > > CONFIG_EXT4_KUNIT_TESTS=y. > > > > A simpler reprducer is to have a .kunitconfig containing: > > > > CONFIG_KUNIT=y > > CONFIG_KUNIT_TEST=y > > CONFIG_KUNIT_EXAMPLE_TEST=y > > CONFIG_EXT4_KUNIT_TESTS=y > > > > ... and then run :./tools/testing/kunit/kunit.py run". > > > > The first failure is actually with [11/17] ext4: fix largest free > > orders lists corruption on mb_optimize_scan switch, which triggers a > > failure of test_mb_mark_used. > > > > Baokun, can you take a look please? Many thanks! > > > > Hi Ted and Guenter, > > I'm sorry for this regression, we didn't run these tests. Baokun is > currently on a business trip, so I help to look into this issue. The > reason for the failure is that the variable initialization in the > mb unit tests are insufficient, but this series relies on them. > > Could you please try the following diff? I have tested it on my > machine, and the issue does not recur. If every thing looks fine, I > will send out the official patch. > Confirmed to fix the problem. Please feel free to add Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx> Thanks, Guenter > Thanks, > Yi. > > > diff --git a/fs/ext4/mballoc-test.c b/fs/ext4/mballoc-test.c > index d634c12f1984..a9416b20ff64 100644 > --- a/fs/ext4/mballoc-test.c > +++ b/fs/ext4/mballoc-test.c > @@ -155,6 +155,7 @@ static struct super_block *mbt_ext4_alloc_super_block(void) > bgl_lock_init(sbi->s_blockgroup_lock); > > sbi->s_es = &fsb->es; > + sbi->s_sb = sb; > sb->s_fs_info = sbi; > > up_write(&sb->s_umount); > @@ -802,6 +803,8 @@ static void test_mb_mark_used(struct kunit *test) > KUNIT_ASSERT_EQ(test, ret, 0); > > grp->bb_free = EXT4_CLUSTERS_PER_GROUP(sb); > + grp->bb_largest_free_order = -1; > + grp->bb_avg_fragment_size_order = -1; > mbt_generate_test_ranges(sb, ranges, TEST_RANGE_COUNT); > for (i = 0; i < TEST_RANGE_COUNT; i++) > test_mb_mark_used_range(test, &e4b, ranges[i].start, > @@ -875,6 +878,8 @@ static void test_mb_free_blocks(struct kunit *test) > ext4_unlock_group(sb, TEST_GOAL_GROUP); > > grp->bb_free = 0; > + grp->bb_largest_free_order = -1; > + grp->bb_avg_fragment_size_order = -1; > memset(bitmap, 0xff, sb->s_blocksize); > > mbt_generate_test_ranges(sb, ranges, TEST_RANGE_COUNT); > > >
