on 3/21/2024 3:16 PM, Kemeng Shi wrote: > > > on 3/21/2024 12:23 AM, Guenter Roeck wrote: >> 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 for the report. The backtrace is not expected, I will look into this. Thansk! >> Hi Guenter, I could not reproduce this in my local vm. From the reported backtraces, it's likely there is a out-of-bounds write to sbi->s_buddy_cache. I try to fix this in [1] and it works fine in my local vm. I wish this work for you to elimate the reported nosie. Look forward to your reply, Thanks. Kemeng [1] https://lore.kernel.org/linux-ext4/20240322165518.8147-1-shikemeng@xxxxxxxxxxxxxxx/T/#u >> Thanks, >> Guenter >>
