================================================================== BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:101 [inline] BUG: KASAN: use-after-free in atomic_inc include/asm-generic/atomic-instrumented.h:240 [inline] BUG: KASAN: use-after-free in lo_open+0x93/0xc0 drivers/block/loop.c:1894 Write of size 4 at addr ffff88810e1c6804 by task udevd/409 CPU: 0 PID: 409 Comm: udevd Not tainted 5.10.117-syzkaller-986967-g0974b8411a58-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118 print_address_description+0x81/0x3c0 mm/kasan/report.c:233 __kasan_report mm/kasan/report.c:419 [inline] kasan_report+0x1a4/0x1f0 mm/kasan/report.c:436 check_region_inline mm/kasan/generic.c:135 [inline] kasan_check_range+0x2aa/0x2e0 mm/kasan/generic.c:186 __kasan_check_write+0x14/0x20 mm/kasan/shadow.c:37 instrument_atomic_read_write include/linux/instrumented.h:101 [inline] atomic_inc include/asm-generic/atomic-instrumented.h:240 [inline] lo_open+0x93/0xc0 drivers/block/loop.c:1894 __blkdev_get+0x599/0x1360 fs/block_dev.c:1511 blkdev_get fs/block_dev.c:1651 [inline] blkdev_open+0x21a/0x450 fs/block_dev.c:1768 do_dentry_open+0x7a2/0x1090 fs/open.c:819 vfs_open+0x73/0x80 fs/open.c:942 do_open fs/namei.c:3327 [inline] path_openat+0x2638/0x2fd0 fs/namei.c:3444 do_filp_open+0x200/0x440 fs/namei.c:3471 do_sys_openat2+0x13b/0x470 fs/open.c:1211 do_sys_open fs/open.c:1227 [inline] __do_sys_openat fs/open.c:1243 [inline] __se_sys_openat fs/open.c:1238 [inline] __x64_sys_openat+0x243/0x290 fs/open.c:1238 do_syscall_64+0x34/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f6735ee5697 Code: 25 00 00 41 00 3d 00 00 41 00 74 37 64 8b 04 25 18 00 00 00 85 c0 75 5b 44 89 e2 48 89 ee bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 85 00 00 00 48 83 c4 68 5d 41 5c c3 0f 1f RSP: 002b:00007ffcc496b680 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 000055a708caf850 RCX: 00007f6735ee5697 RDX: 00000000000a0800 RSI: 000055a708c834d0 RDI: 00000000ffffff9c RBP: 000055a708c834d0 R08: 00000000ffffffff R09: 00007ffcc49aa0b8 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000a0800 R13: 000055a708c85b00 R14: 0000000000000001 R15: 000055a708c772c0 Allocated by task 419: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:428 [inline] ____kasan_kmalloc+0xdc/0x110 mm/kasan/common.c:507 __kasan_kmalloc+0x9/0x10 mm/kasan/common.c:516 kasan_kmalloc include/linux/kasan.h:269 [inline] kmem_cache_alloc_trace+0x1dd/0x330 mm/slub.c:2983 kmalloc include/linux/slab.h:552 [inline] kzalloc include/linux/slab.h:664 [inline] loop_add+0x5a/0x770 drivers/block/loop.c:2083 loop_control_ioctl+0x564/0x740 drivers/block/loop.c:2294 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl+0x115/0x190 fs/ioctl.c:739 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:739 do_syscall_64+0x34/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 419: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4c/0x80 mm/kasan/common.c:46 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:357 ____kasan_slab_free+0x121/0x160 mm/kasan/common.c:360 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:368 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:1604 [inline] slab_free_freelist_hook+0xcc/0x1a0 mm/slub.c:1630 slab_free mm/slub.c:3212 [inline] kfree+0xc3/0x290 mm/slub.c:4200 loop_add+0x591/0x770 drivers/block/loop.c:2182 loop_control_ioctl+0x564/0x740 drivers/block/loop.c:2294 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl+0x115/0x190 fs/ioctl.c:739 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:739 do_syscall_64+0x34/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff88810e1c6800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 4 bytes inside of 1024-byte region [ffff88810e1c6800, ffff88810e1c6c00) The buggy address belongs to the page: page:ffffea0004387000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10e1c0 head:ffffea0004387000 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x8000000000010200(slab|head) raw: 8000000000010200 dead000000000100 dead000000000122 ffff888100042f00 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d2000(__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 417, ts 38198213792, free_ts 38194810139 set_page_owner include/linux/page_owner.h:35 [inline] post_alloc_hook mm/page_alloc.c:2385 [inline] prep_new_page mm/page_alloc.c:2391 [inline] get_page_from_freelist+0x745/0x760 mm/page_alloc.c:4067 __alloc_pages_nodemask+0x3b6/0x890 mm/page_alloc.c:5117 alloc_slab_page mm/slub.c:1815 [inline] allocate_slab+0x78/0x540 mm/slub.c:1817 new_slab mm/slub.c:1878 [inline] new_slab_objects mm/slub.c:2637 [inline] ___slab_alloc+0x131/0x2e0 mm/slub.c:2800 __slab_alloc+0x63/0xa0 mm/slub.c:2840 slab_alloc_node mm/slub.c:2922 [inline] slab_alloc mm/slub.c:2964 [inline] __kmalloc+0x24f/0x360 mm/slub.c:4038 __kmalloc_node include/linux/slab.h:418 [inline] kmalloc_node include/linux/slab.h:575 [inline] kzalloc_node include/linux/slab.h:675 [inline] blk_mq_alloc_hctx block/blk-mq.c:2786 [inline] blk_mq_alloc_and_init_hctx block/blk-mq.c:3217 [inline] blk_mq_realloc_hw_ctxs+0x4bb/0x1840 block/blk-mq.c:3269 blk_mq_init_allocated_queue+0x41a/0x1a30 block/blk-mq.c:3331 blk_mq_init_queue_data block/blk-mq.c:3150 [inline] blk_mq_init_queue+0x6c/0xc0 block/blk-mq.c:3160 loop_add+0x26c/0x770 drivers/block/loop.c:2115 loop_control_ioctl+0x564/0x740 drivers/block/loop.c:2294 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl+0x115/0x190 fs/ioctl.c:739 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:739 do_syscall_64+0x34/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 page last free stack trace: reset_page_owner include/linux/page_owner.h:28 [inline] free_pages_prepare mm/page_alloc.c:1331 [inline] __free_pages_ok+0x7f8/0x830 mm/page_alloc.c:1611 free_the_page mm/page_alloc.c:5178 [inline] __free_pages+0x2d2/0x4c0 mm/page_alloc.c:5184 __free_slab+0xd3/0x190 mm/slub.c:1903 free_slab mm/slub.c:1918 [inline] discard_slab mm/slub.c:1924 [inline] unfreeze_partials+0x17d/0x1b0 mm/slub.c:2418 put_cpu_partial+0xc8/0x190 mm/slub.c:2454 __slab_free+0x2d8/0x3a0 mm/slub.c:3104 do_slab_free mm/slub.c:3200 [inline] ___cache_free+0x11f/0x140 mm/slub.c:3219 qlink_free+0x38/0x40 mm/kasan/quarantine.c:146 qlist_free_all+0x4c/0xc0 mm/kasan/quarantine.c:165 kasan_quarantine_reduce+0x15a/0x170 mm/kasan/quarantine.c:272 __kasan_slab_alloc+0x2f/0xe0 mm/kasan/common.c:438 kasan_slab_alloc include/linux/kasan.h:259 [inline] slab_post_alloc_hook mm/slab.h:583 [inline] slab_alloc_node mm/slub.c:2956 [inline] slab_alloc mm/slub.c:2964 [inline] kmem_cache_alloc+0x16c/0x300 mm/slub.c:2969 getname_flags+0xba/0x510 fs/namei.c:141 user_path_at_empty+0x2d/0x50 fs/namei.c:2726 user_path_at include/linux/namei.h:59 [inline] ksys_umount fs/namespace.c:1761 [inline] __do_sys_umount fs/namespace.c:1769 [inline] __se_sys_umount fs/namespace.c:1767 [inline] __x64_sys_umount+0xf0/0x170 fs/namespace.c:1767 do_syscall_64+0x34/0x70 arch/x86/entry/common.c:46 Memory state around the buggy address: ffff88810e1c6700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88810e1c6780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88810e1c6800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88810e1c6880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88810e1c6900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 0 PID: 409 at lib/refcount.c:25 refcount_warn_saturate+0x147/0x1b0 lib/refcount.c:25 Modules linked in: CPU: 0 PID: 409 Comm: udevd Tainted: G B 5.10.117-syzkaller-986967-g0974b8411a58-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:refcount_warn_saturate+0x147/0x1b0 lib/refcount.c:25 Code: c7 a0 bc 43 85 31 c0 e8 57 22 f2 fe 0f 0b eb a1 e8 ee e7 1f ff c6 05 7a 6c 0f 04 01 48 c7 c7 20 bd 43 85 31 c0 e8 39 22 f2 fe <0f> 0b eb 83 e8 d0 e7 1f ff c6 05 5d 6c 0f 04 01 48 c7 c7 80 bd 43 RSP: 0018:ffffc90000cc7670 EFLAGS: 00010246 RAX: eb619ca7038f9500 RBX: 0000000000000002 RCX: ffff88810b8c2780 RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000 RBP: ffffc90000cc7680 R08: ffffffff8153a998 R09: fffff52000198df5 R10: fffff52000198df5 R11: 1ffff92000198df4 R12: dffffc0000000000 R13: ffff88810e196000 R14: 0000000000000002 R15: ffff88810e196000 FS: 00007f6735d8e840(0000) GS:ffff8881f7200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f340fa3aff8 CR3: 000000010d780000 CR4: 00000000003506b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __refcount_add include/linux/refcount.h:200 [inline] __refcount_inc include/linux/refcount.h:250 [inline] refcount_inc include/linux/refcount.h:267 [inline] kref_get include/linux/kref.h:45 [inline] bdi_get+0x83/0x90 include/linux/backing-dev.h:24 __blkdev_get+0x120c/0x1360 fs/block_dev.c:1554 blkdev_get fs/block_dev.c:1651 [inline] blkdev_open+0x21a/0x450 fs/block_dev.c:1768 do_dentry_open+0x7a2/0x1090 fs/open.c:819 vfs_open+0x73/0x80 fs/open.c:942 do_open fs/namei.c:3327 [inline] path_openat+0x2638/0x2fd0 fs/namei.c:3444 do_filp_open+0x200/0x440 fs/namei.c:3471 do_sys_openat2+0x13b/0x470 fs/open.c:1211 do_sys_open fs/open.c:1227 [inline] __do_sys_openat fs/open.c:1243 [inline] __se_sys_openat fs/open.c:1238 [inline] __x64_sys_openat+0x243/0x290 fs/open.c:1238 do_syscall_64+0x34/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f6735ee5697 Code: 25 00 00 41 00 3d 00 00 41 00 74 37 64 8b 04 25 18 00 00 00 85 c0 75 5b 44 89 e2 48 89 ee bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 85 00 00 00 48 83 c4 68 5d 41 5c c3 0f 1f RSP: 002b:00007ffcc496b680 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 000055a708caf850 RCX: 00007f6735ee5697 RDX: 00000000000a0800 RSI: 000055a708c834d0 RDI: 00000000ffffff9c RBP: 000055a708c834d0 R08: 00000000ffffffff R09: 00007ffcc49aa0b8 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000a0800 R13: 000055a708c85b00 R14: 0000000000000001 R15: 000055a708c772c0 ---[ end trace 2c2d8a6f4678f13e ]--- udevd[409]: inotify_add_watch(7, /dev/loop0, 10) failed: No such file or directory