================================================================== BUG: KASAN: slab-use-after-free in snapshot_ctr+0x5cb/0x1340 drivers/md/dm-snap.c:1282 Read of size 8 at addr ffff888035047398 by task syz.0.0/5331 CPU: 0 UID: 0 PID: 5331 Comm: syz.0.0 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_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 snapshot_ctr+0x5cb/0x1340 drivers/md/dm-snap.c:1282 dm_table_add_target+0x58d/0xc70 drivers/md/dm-table.c:749 populate_table drivers/md/dm-ioctl.c:1602 [inline] table_load+0x325/0x8a0 drivers/md/dm-ioctl.c:1645 ctl_ioctl drivers/md/dm-ioctl.c:2221 [inline] dm_ctl_ioctl+0x9ec/0xe10 drivers/md/dm-ioctl.c:2243 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f412599f559 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f4121df4fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f4125c25fa0 RCX: 00007f412599f559 RDX: 0000200000000580 RSI: 00000000c138fd09 RDI: 0000000000000003 RBP: 00007f4125a36b20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4125c26038 R14: 00007f4125c25fa0 R15: 00007fff0ee75058 Allocated by task 5331: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:409 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:426 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_node_noprof+0x3cc/0x620 mm/slub.c:5582 _kmalloc_node_noprof include/linux/slab.h:1196 [inline] open_table_device drivers/md/dm.c:733 [inline] dm_get_table_device+0x23e/0x730 drivers/md/dm.c:821 dm_get_device+0x327/0x760 drivers/md/dm-table.c:388 snapshot_ctr+0x2b2/0x1340 drivers/md/dm-snap.c:1267 dm_table_add_target+0x58d/0xc70 drivers/md/dm-table.c:749 populate_table drivers/md/dm-ioctl.c:1602 [inline] table_load+0x325/0x8a0 drivers/md/dm-ioctl.c:1645 ctl_ioctl drivers/md/dm-ioctl.c:2221 [inline] dm_ctl_ioctl+0x9ec/0xe10 drivers/md/dm-ioctl.c:2243 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 5331: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:264 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:296 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2748 [inline] slab_free mm/slub.c:6509 [inline] kfree+0x1c5/0x650 mm/slub.c:6802 close_table_device drivers/md/dm.c:798 [inline] dm_put_table_device+0x255/0x2a0 drivers/md/dm.c:841 upgrade_mode drivers/md/dm-table.c:326 [inline] dm_get_device+0x56f/0x760 drivers/md/dm-table.c:399 snapshot_ctr+0x471/0x1340 drivers/md/dm-snap.c:1277 dm_table_add_target+0x58d/0xc70 drivers/md/dm-table.c:749 populate_table drivers/md/dm-ioctl.c:1602 [inline] table_load+0x325/0x8a0 drivers/md/dm-ioctl.c:1645 ctl_ioctl drivers/md/dm-ioctl.c:2221 [inline] dm_ctl_ioctl+0x9ec/0xe10 drivers/md/dm-ioctl.c:2243 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888035047380 which belongs to the cache kmalloc-96 of size 96 The buggy address is located 24 bytes inside of freed 96-byte region [ffff888035047380, ffff8880350473e0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888035047480 pfn:0x35047 flags: 0x4fff00000000200(workingset|node=1|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 04fff00000000200 ffff88801c041280 ffff8880304001c8 ffffea0000d31450 raw: ffff888035047480 0000000000200017 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 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 19591866357 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1871 prep_new_page mm/page_alloc.c:1879 [inline] get_page_from_freelist+0x2209/0x2280 mm/page_alloc.c:3943 __alloc_frozen_pages_noprof+0x217/0x5a0 mm/page_alloc.c:5436 alloc_slab_page mm/slub.c:3347 [inline] allocate_slab+0x7d/0x620 mm/slub.c:3462 new_slab mm/slub.c:3513 [inline] refill_objects+0x2d5/0x350 mm/slub.c:7418 refill_sheaf mm/slub.c:2885 [inline] __pcs_replace_empty_main+0x2c8/0x6c0 mm/slub.c:4774 alloc_from_pcs mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:4984 [inline] __kmalloc_cache_node_noprof+0x446/0x620 mm/slub.c:5578 _kmalloc_node_noprof include/linux/slab.h:1196 [inline] __get_vm_area_node+0x155/0x2f0 mm/vmalloc.c:3237 __vmalloc_node_range_noprof+0x343/0x1540 mm/vmalloc.c:4064 __vmalloc_node_noprof mm/vmalloc.c:4165 [inline] vzalloc_noprof+0xb2/0xe0 mm/vmalloc.c:4243 tpg_alloc+0x116/0x860 drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:124 vivid_create_instance drivers/media/test-drivers/vivid/vivid-core.c:1857 [inline] vivid_probe+0x1b55/0x70c0 drivers/media/test-drivers/vivid/vivid-core.c:2095 platform_probe+0xf9/0x190 drivers/base/platform.c:1508 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x254/0xae0 drivers/base/dd.c:706 __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868 driver_probe_device+0x4f/0x240 drivers/base/dd.c:898 page last free pid 1 tgid 1 ts 19591817283 stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] __free_frozen_pages+0xc93/0xd90 mm/page_alloc.c:2962 __kasan_populate_vmalloc_do mm/kasan/shadow.c:393 [inline] __kasan_populate_vmalloc+0x1a8/0x1c0 mm/kasan/shadow.c:424 kasan_populate_vmalloc include/linux/kasan.h:580 [inline] alloc_vmap_area+0xd10/0x1410 mm/vmalloc.c:2145 __get_vm_area_node+0x200/0x2f0 mm/vmalloc.c:3248 __vmalloc_node_range_noprof+0x343/0x1540 mm/vmalloc.c:4064 __vmalloc_node_noprof mm/vmalloc.c:4165 [inline] vzalloc_noprof+0xb2/0xe0 mm/vmalloc.c:4243 tpg_alloc+0xdc/0x860 drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:132 vivid_create_instance drivers/media/test-drivers/vivid/vivid-core.c:1857 [inline] vivid_probe+0x1b55/0x70c0 drivers/media/test-drivers/vivid/vivid-core.c:2095 platform_probe+0xf9/0x190 drivers/base/platform.c:1508 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x254/0xae0 drivers/base/dd.c:706 __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868 driver_probe_device+0x4f/0x240 drivers/base/dd.c:898 __driver_attach+0x339/0x600 drivers/base/dd.c:1292 bus_for_each_dev+0x23b/0x2c0 drivers/base/bus.c:386 bus_add_driver+0x38f/0x6e0 drivers/base/bus.c:771 driver_register+0x23a/0x320 drivers/base/driver.c:174 Memory state around the buggy address: ffff888035047280: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff888035047300: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc >ffff888035047380: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ^ ffff888035047400: 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc ffff888035047480: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ==================================================================