Re: [PATCH v2 2/5] ext4: Add unit test of ext4_mb_generate_buddy
From: Guenter Roeck
Date: Wed Mar 20 2024 - 12:23:38 EST
Hi,
On Wed, Jan 03, 2024 at 06:48:57PM +0800, Kemeng Shi wrote:
> Add unit test of ext4_mb_generate_buddy
>
> Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>
With this and other new ext4 tests test in the tree, I see a variety
of backtraces in the upstream kernel if debug options are enabled.
An example is
[ 6.821447] KTAP version 1
[ 6.821769] # Subtest: test_mb_generate_buddy
[ 6.824787] =============================================================================
[ 6.825568] BUG inode_cache (Tainted: G N): Padding overwritten. 0xfffff80006223f68-0xfffff80006223f6f @offset=16232
..
[ 6.894341] ok 7 ext4_inode_test
[ 6.895411] =============================================================================
[ 6.895777] BUG inode_cache (Tainted: G B N): Padding overwritten. 0xfffff80006223f68-0xfffff80006223f6f @offset=16232
Another example, from another test run, is
[ 3.938551] # Subtest: test_new_blocks_simple
[ 3.947171] ok 1 block_bits=10 cluster_bits=3 blocks_per_group=8192 group_count=4 desc_size=64
[ 3.952988] ok 2 block_bits=12 cluster_bits=3 blocks_per_group=8192 group_count=4 desc_size=64
[ 3.958403] ok 3 block_bits=16 cluster_bits=3 blocks_per_group=8192 group_count=4 desc_size=64
[ 3.958890] =============================================================================
[ 3.959159] BUG inode_cache (Tainted: G N): Padding overwritten. 0xffff8de881adbf68-0xffff8de881adbf6f @offset=16232
Another one:
[ 18.730473] # Subtest: test_new_blocks_simple
[ 18.760547] ok 1 block_bits=10 cluster_bits=3 blocks_per_group=8192 group_count=4 desc_size=64
[ 18.778477] ==================================================================
[ 18.778950] BUG: KFENCE: out-of-bounds write in ext4_mb_init+0x5d7/0xa60
This is just a sample, taken from a quick look at test results.
Are those backtraces expected ? If so, would it be possible to execute the
tests without generating such backtraces ? The backtraces, if intentional,
hide real problems in the noise.
Thanks,
Guenter