Hi Christoph, I tried enabling kmemleak on 4.7-rc2 on an x86 host (macbook pro running Debian sid) and I get some kmemleak reports every few minutes coming from the block layer. Reverting commit 9082e87bfbf8 ("block: remove struct bio_batch") makes them go away: unreferenced object 0xffff880077859c00 (size 256): comm "upowerd", pid 1185, jiffies 4295046823 (age 1874.852s) hex dump (first 32 bytes): 80 39 08 00 00 ea ff ff 00 10 00 00 00 00 00 00 .9.............. 00 00 00 00 00 00 00 00 00 e4 21 49 02 88 ff ff ..........!I.... backtrace: [<ffffffff811d244e>] kmem_cache_alloc+0xfe/0x250 [<ffffffff812dc8b7>] bvec_alloc+0x57/0xe0 [<ffffffff812dcaaf>] bio_alloc_bioset+0x16f/0x240 [<ffffffff812eca7f>] next_bio+0x1f/0x50 [<ffffffff812ecf1a>] blkdev_issue_zeroout+0xea/0x1d0 [<ffffffffc025b610>] ext4_issue_zeroout+0x40/0x50 [ext4] [<ffffffffc028c58d>] ext4_ext_map_blocks+0x144d/0x1bb0 [ext4] [<ffffffff811839f4>] release_pages+0x254/0x310 [<ffffffff8118437a>] __pagevec_release+0x2a/0x40 [<ffffffffc025b297>] mpage_prepare_extent_to_map+0x227/0x2c0 [ext4] [<ffffffffc025b793>] ext4_map_blocks+0x173/0x5d0 [ext4] [<ffffffffc025f1d0>] ext4_writepages+0x700/0xd40 [ext4] [<ffffffff8121312e>] legitimize_mnt+0xe/0x50 [<ffffffff811d244e>] kmem_cache_alloc+0xfe/0x250 [<ffffffff81173fd5>] __filemap_fdatawrite_range+0xc5/0x100 [<ffffffff81174113>] filemap_write_and_wait_range+0x33/0x70 It's coming from various processes, not just upowerd. I haven't got the chance to dig further but you may have a better idea. Thanks. -- Catalin -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html