================================================================== BUG: KASAN: slab-out-of-bounds in blk_mq_free_rqs+0x6e2/0x760 block/blk-mq.c:3510 Read of size 8 at addr ffff8880280d4828 by task syz-executor.0/5994 CPU: 2 UID: 0 PID: 5994 Comm: syz-executor.0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x13d/0x4b0 mm/kasan/report.c:482 kasan_report+0xdf/0x1d0 mm/kasan/report.c:595 blk_mq_free_rqs+0x6e2/0x760 block/blk-mq.c:3510 blk_mq_free_map_and_rqs block/blk-mq.c:4181 [inline] blk_mq_free_map_and_rqs+0x30/0x120 block/blk-mq.c:4176 blk_mq_free_sched_tags+0xeb/0x1b0 block/blk-mq-sched.c:425 blk_mq_free_sched_res+0x52/0x150 block/blk-mq-sched.c:436 elevator_change_done+0x187/0x650 block/elevator.c:639 elevator_change+0x2d7/0x530 block/elevator.c:685 elevator_set_none+0x92/0xf0 block/elevator.c:769 blk_mq_elv_switch_none block/blk-mq.c:5134 [inline] __blk_mq_update_nr_hw_queues block/blk-mq.c:5179 [inline] blk_mq_update_nr_hw_queues+0x4c1/0x15f0 block/blk-mq.c:5244 nbd_start_device+0x1a6/0xbd0 drivers/block/nbd.c:1489 nbd_start_device_ioctl drivers/block/nbd.c:1548 [inline] __nbd_ioctl drivers/block/nbd.c:1623 [inline] nbd_ioctl+0x4a6/0xd30 drivers/block/nbd.c:1663 blkdev_ioctl+0x5ad/0x6f0 block/ioctl.c:797 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f20f2a6d179 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 d0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f20f37e3078 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f20f2babf80 RCX: 00007f20f2a6d179 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000007 RBP: 00007f20f37e30e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002 R13: 000000000000000b R14: 00007f20f2babf80 R15: 00007ffc1be217a8 Allocated by task 1: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5296 [inline] __kmalloc_node_noprof+0x307/0x850 mm/slub.c:5302 kmalloc_array_node_noprof include/linux/slab.h:1169 [inline] blk_mq_alloc_tag_set+0x477/0x1330 block/blk-mq.c:4927 nbd_dev_add+0x342/0xb10 drivers/block/nbd.c:1933 nbd_init+0x291/0x2b0 drivers/block/nbd.c:2692 do_one_initcall+0x121/0x750 init/main.c:1392 do_initcall_level init/main.c:1454 [inline] do_initcalls init/main.c:1470 [inline] do_basic_setup init/main.c:1490 [inline] kernel_init_freeable+0x6ea/0x7b0 init/main.c:1703 kernel_init+0x1f/0x1e0 init/main.c:1593 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 The buggy address belongs to the object at ffff8880280d4820 which belongs to the cache kmalloc-8 of size 8 The buggy address is located 0 bytes to the right of allocated 8-byte region [ffff8880280d4820, ffff8880280d4828) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880280d4460 pfn:0x280d4 flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000200 ffff88801b842500 ffffea00009f6190 ffffea0000a1f610 raw: ffff8880280d4460 000000080080007f 00000000f5000000 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2c00(GFP_NOIO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 12042019816, free_ts 6231045139 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1853 prep_new_page mm/page_alloc.c:1861 [inline] get_page_from_freelist+0x11a6/0x3410 mm/page_alloc.c:3941 __alloc_frozen_pages_noprof+0x27c/0x2bc0 mm/page_alloc.c:5221 alloc_slab_page mm/slub.c:3278 [inline] allocate_slab mm/slub.c:3467 [inline] new_slab+0xa6/0x6c0 mm/slub.c:3525 refill_objects+0x277/0x420 mm/slub.c:7272 refill_sheaf mm/slub.c:2816 [inline] __pcs_replace_empty_main+0x375/0x650 mm/slub.c:4652 alloc_from_pcs mm/slub.c:4750 [inline] slab_alloc_node mm/slub.c:4884 [inline] __do_kmalloc_node mm/slub.c:5295 [inline] __kmalloc_node_track_caller_noprof+0x694/0x850 mm/slub.c:5408 __kmemdup_nul mm/util.c:64 [inline] kstrdup+0x51/0xe0 mm/util.c:84 kstrdup_const+0x63/0x80 mm/util.c:104 __kernfs_new_node+0x9b/0x9f0 fs/kernfs/dir.c:660 kernfs_new_node+0x11b/0x1a0 fs/kernfs/dir.c:748 kernfs_create_dir_ns+0x4c/0x1a0 fs/kernfs/dir.c:1121 sysfs_create_dir_ns+0x13a/0x2b0 fs/sysfs/dir.c:59 create_dir lib/kobject.c:73 [inline] kobject_add_internal+0x2c8/0x930 lib/kobject.c:240 kobject_add_varg lib/kobject.c:374 [inline] kobject_add+0x16a/0x1e0 lib/kobject.c:426 blk_mq_register_hctx+0x124/0x460 block/blk-mq-sysfs.c:168 page last free pid 55 tgid 55 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1397 [inline] __free_frozen_pages+0x794/0x10a0 mm/page_alloc.c:2938 vfree mm/vmalloc.c:3472 [inline] vfree+0x15f/0x8d0 mm/vmalloc.c:3436 delayed_vfree_work+0x56/0x80 mm/vmalloc.c:3392 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3314 process_scheduled_works kernel/workqueue.c:3397 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff8880280d4700: fa fc fc fc fa fc fc fc 05 fc fc fc 05 fc fc fc ffff8880280d4780: 05 fc fc fc 05 fc fc fc 05 fc fc fc 00 fc fc fc >ffff8880280d4800: 05 fc fc fc 00 fc fc fc 05 fc fc fc 05 fc fc fc ^ ffff8880280d4880: 05 fc fc fc 05 fc fc fc 05 fc fc fc 05 fc fc fc ffff8880280d4900: 05 fc fc fc 05 fc fc fc 05 fc fc fc 05 fc fc fc ==================================================================