This is only reproducible on linux-next (20190221), as v5.0-rc7 is fine. Running two LTP tests and then reboot will trigger this on ppc64le (CONFIG_IO_URING=n and CONFIG_SHUFFLE_PAGE_ALLOCATOR=y). # fgetxattr02 # io_submit01 # systemctl reboot There is a 32-bit (with all ones) overwritten of free slab objects (poisoned). [23424.121182] BUG aio_kiocb (Tainted: G B W L ): Poison overwritten [23424.121189] ----------------------------------------------------------------------------- [23424.121189] [23424.121197] INFO: 0x000000009f1f5145-0x00000000841e301b. First byte 0xff instead of 0x6b [23424.121205] INFO: Allocated in io_submit_one+0x9c/0xb20 age=0 cpu=7 pid=12174 [23424.121212] __slab_alloc+0x34/0x60 [23424.121217] kmem_cache_alloc+0x504/0x5c0 [23424.121221] io_submit_one+0x9c/0xb20 [23424.121224] sys_io_submit+0xe0/0x350 [23424.121227] system_call+0x5c/0x70 [23424.121231] INFO: Freed in aio_complete+0x31c/0x410 age=0 cpu=7 pid=12174 [23424.121234] kmem_cache_free+0x4bc/0x540 [23424.121237] aio_complete+0x31c/0x410 [23424.121240] blkdev_bio_end_io+0x238/0x3e0 [23424.121243] bio_endio.part.3+0x214/0x330 [23424.121247] brd_make_request+0x2d8/0x314 [brd] [23424.121250] generic_make_request+0x220/0x510 [23424.121254] submit_bio+0xc8/0x1f0 [23424.121256] blkdev_direct_IO+0x36c/0x610 [23424.121260] generic_file_read_iter+0xbc/0x230 [23424.121263] blkdev_read_iter+0x50/0x80 [23424.121266] aio_read+0x138/0x200 [23424.121269] io_submit_one+0x7c4/0xb20 [23424.121272] sys_io_submit+0xe0/0x350 [23424.121275] system_call+0x5c/0x70 [23424.121278] INFO: Slab 0x00000000841158ec objects=85 used=85 fp=0x (null) flags=0x13fffc000000200 [23424.121282] INFO: Object 0x000000007e677ed8 @offset=5504 fp=0x00000000e42bdf6f [23424.121282] [23424.121287] Redzone 000000005483b8fc: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb ................ [23424.121291] Redzone 00000000b842fe53: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb ................ [23424.121295] Redzone 00000000deb0d052: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb ................ [23424.121299] Redzone 0000000014045233: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb ................ [23424.121302] Redzone 00000000dd5d6c16: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb ................ [23424.121306] Redzone 00000000538b5478: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb ................ [23424.121310] Redzone 000000001f7fb704: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb ................ [23424.121314] Redzone 0000000000e0484d: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb ................ [23424.121318] Object 000000007e677ed8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk [23424.121322] Object 00000000e207f30b: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk [23424.121326] Object 00000000a7a45634: 6b 6b 6b 6b 6b 6b 6b 6b ff ff ff ff 6b 6b 6b 6b kkkkkkkk....kkkk [23424.121330] Object 00000000c85d951d: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk [23424.121334] Object 000000003104522f: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk [23424.121338] Object 00000000cfcdd820: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk [23424.121342] Object 00000000dded4924: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk [23424.121346] Object 00000000ff6687a4: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk [23424.121350] Object 00000000df3d67f6: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk [23424.121354] Object 00000000ddc188d1: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk [23424.121358] Object 000000002cee751a: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk [23424.121362] Object 00000000a994f007: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5 kkkkkkkkkkkkkkk. [23424.121366] Redzone 000000009f3d62e2: bb bb bb bb bb bb bb bb ........ [23424.121370] Padding 00000000e5ccead8: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ [23424.121374] Padding 000000002b0c1778: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ [23424.121378] Padding 00000000c67656c7: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ [23424.121382] Padding 0000000078348c5a: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ [23424.121386] Padding 00000000f3297820: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ [23424.121390] Padding 00000000e55789f4: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ [23424.121394] Padding 00000000d0fbb94c: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ [23424.121397] Padding 00000000bcb27a87: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ [23424.121743] CPU: 7 PID: 12174 Comm: vgs Tainted: G B W L 5.0.0-rc7-next-20190221+ #7 [23424.121758] Call Trace: [23424.121762] [c0000004ce5bf7b0] [c0000000007deb8c] dump_stack+0xb0/0xf4 (unreliable) [23424.121770] [c0000004ce5bf7f0] [c00000000037d310] print_trailer+0x250/0x278 [23424.121775] [c0000004ce5bf880] [c00000000036d578] check_bytes_and_report+0x138/0x160 [23424.121779] [c0000004ce5bf920] [c00000000036fac8] check_object+0x348/0x3e0 [23424.121784] [c0000004ce5bf990] [c00000000036fd18] alloc_debug_processing+0x1b8/0x2c0 [23424.121788] [c0000004ce5bfa30] [c000000000372d14] ___slab_alloc+0xbb4/0xfa0 [23424.121792] [c0000004ce5bfb60] [c000000000373134] __slab_alloc+0x34/0x60 [23424.121802] [c0000004ce5bfb90] [c000000000373664] kmem_cache_alloc+0x504/0x5c0 [23424.121812] [c0000004ce5bfc20] [c000000000476a9c] io_submit_one+0x9c/0xb20 [23424.121824] [c0000004ce5bfd50] [c000000000477f10] sys_io_submit+0xe0/0x350 [23424.121832] [c0000004ce5bfe20] [c00000000000b000] system_call+0x5c/0x70 [23424.121836] FIX aio_kiocb: Restoring 0x000000009f1f5145-0x00000000841e301b=0x6b [23424.121836] [23424.121840] FIX aio_kiocb: Marking all objects used