------------[ cut here ]------------ kernfs_put: syz4/pids.events: released with incorrect active_ref 0 WARNING: CPU: 1 PID: 17257 at fs/kernfs/dir.c:531 kernfs_put.part.0+0x433/0x540 Modules linked in: CPU: 1 PID: 17257 Comm: kworker/1:1 Not tainted 5.19.0-rc4-next-20220701 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 Workqueue: events kernfs_notify_workfn RIP: 0010:kernfs_put.part.0+0x433/0x540 Code: 03 80 3c 18 00 0f 85 ea 00 00 00 4d 8b 7d 38 e8 53 42 a7 ff 48 8b 14 24 44 89 f1 4c 89 fe 48 c7 c7 a0 58 72 84 e8 97 1c 6c 02 <0f> 0b e9 b9 fc ff ff 48 89 ef e8 8e b6 d9 ff e9 c1 fd ff ff e8 84 RSP: 0018:ffff888046b3fbd8 EFLAGS: 00010286 RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000 RDX: ffff888044ee1ac0 RSI: ffffffff812b6848 RDI: ffffed1008d67f6d RBP: ffff888017c5b3d8 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000080000000 R11: 0000000000000001 R12: ffff888017c5b3a0 ------------[ cut here ]------------ R13: ffff88801d158000 R14: 0000000000000000 R15: ffff88803f8a97d0 FS: 0000000000000000(0000) GS:ffff88806cf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffdea5d6d78 CR3: 000000001d3d8000 CR4: 0000000000350ee0 WARNING: CPU: 0 PID: 13 at fs/kernfs/dir.c:504 kernfs_get.part.0+0x69/0x80 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 Modules linked in: CPU: 0 PID: 13 Comm: ksoftirqd/0 Not tainted 5.19.0-rc4-next-20220701 #1 DR3: 0000000000000000 DR6: 00000000ffff4ff0 DR7: 0000000000000400 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 Call Trace: RIP: 0010:kernfs_get.part.0+0x69/0x80 kernfs_put+0x42/0x50 Code: 31 ff 89 ee e8 a8 43 a7 ff 85 ed 74 18 e8 cf 46 a7 ff be 04 00 00 00 48 89 df e8 52 be d9 ff f0 ff 03 5b 5d c3 e8 b7 46 a7 ff <0f> 0b eb df 48 89 df e8 fb ba d9 ff eb c6 66 0f 1f 84 00 00 00 00 kernfs_notify_workfn+0x417/0x560 RSP: 0018:ffff88800825fb68 EFLAGS: 00010046 RAX: 0000000000000000 RBX: ffff888017c5b3a0 RCX: 0000000000000100 RDX: ffff888008250000 RSI: ffffffff819d2579 RDI: 0000000000000005 process_one_work+0xa0f/0x1690 RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000001 R13: 1ffffffff0a01e40 R14: ffff888017c5b3a0 R15: ffff88800f955930 FS: 0000000000000000(0000) GS:ffff88806ce00000(0000) knlGS:0000000000000000 worker_thread+0x637/0x1250 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f88d2988010 CR3: 0000000046aca000 CR4: 0000000000350ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 kthread+0x2ed/0x3a0 DR3: 0000000000000000 DR6: 00000000ffff4ff0 DR7: 0000000000000400 Call Trace: ret_from_fork+0x22/0x30 kernfs_get+0x1b/0x30 irq event stamp: 147845 kernfs_notify+0x180/0x350 hardirqs last enabled at (147855): [] console_emit_next_record.constprop.0+0x648/0x800 cgroup_file_notify+0xf5/0x1a0 hardirqs last disabled at (147862): [] console_emit_next_record.constprop.0+0x667/0x800 softirqs last enabled at (146046): [] __irq_exit_rcu+0x113/0x170 call_timer_fn+0x17d/0x5f0 softirqs last disabled at (146041): [] __irq_exit_rcu+0x113/0x170 ---[ end trace 0000000000000000 ]--- ================================================================== BUG: KASAN: use-after-free in llist_del_first+0x89/0xa0 Read of size 8 at addr ffff888017c5b420 by task kworker/1:1/17257 CPU: 1 PID: 17257 Comm: kworker/1:1 Tainted: G W 5.19.0-rc4-next-20220701 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 __run_timers.part.0+0x65e/0xa50 Workqueue: events kernfs_notify_workfn Call Trace: dump_stack_lvl+0x8b/0xb3 print_report.cold+0x5e/0x5e1 kasan_report+0xb1/0x1b0 run_timer_softirq+0xae/0x1a0 __do_softirq+0x1c8/0x8cc llist_del_first+0x89/0xa0 kernfs_notify_workfn+0x78/0x560 run_ksoftirqd+0x2d/0x60 smpboot_thread_fn+0x66f/0xa00 kthread+0x2ed/0x3a0 process_one_work+0xa0f/0x1690 ret_from_fork+0x22/0x30 irq event stamp: 14645511 worker_thread+0x637/0x1250 hardirqs last enabled at (14645510): [] _raw_spin_unlock_irq+0x1f/0x40 hardirqs last disabled at (14645511): [] _raw_spin_lock_irqsave+0x4e/0x50 softirqs last enabled at (14645498): [] run_ksoftirqd+0x2d/0x60 kthread+0x2ed/0x3a0 softirqs last disabled at (14645503): [] run_ksoftirqd+0x2d/0x60 ---[ end trace 0000000000000000 ]--- ret_from_fork+0x22/0x30 Allocated by task 294: kasan_save_stack+0x1e/0x40 __kasan_slab_alloc+0x66/0x80 kmem_cache_alloc+0x1b1/0x490 __kernfs_new_node+0xd4/0x8b0 kernfs_new_node+0x93/0x120 __kernfs_create_file+0x51/0x350 cgroup_addrm_files+0x3e2/0x9d0 css_populate_dir+0x19b/0x450 cgroup_apply_control_enable+0x3ae/0xa40 cgroup_mkdir+0x824/0x11f0 kernfs_iop_mkdir+0x149/0x1d0 vfs_mkdir+0x417/0x6a0 do_mkdirat+0x17b/0x2e0 __x64_sys_mkdir+0xf2/0x140 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x46/0xb0 Freed by task 17257: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 kasan_set_free_info+0x20/0x30 __kasan_slab_free+0x108/0x190 kmem_cache_free+0xfb/0x600 kernfs_put.part.0+0x2c7/0x540 kernfs_put+0x42/0x50 kernfs_notify_workfn+0x417/0x560 process_one_work+0xa0f/0x1690 worker_thread+0x637/0x1250 kthread+0x2ed/0x3a0 ret_from_fork+0x22/0x30 The buggy address belongs to the object at ffff888017c5b3a0 which belongs to the cache kernfs_node_cache of size 168 The buggy address is located 128 bytes inside of 168-byte region [ffff888017c5b3a0, ffff888017c5b448) The buggy address belongs to the physical page: page:00000000e2ad4d55 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x17c5b flags: 0x100000000000200(slab|node=0|zone=1) raw: 0100000000000200 0000000000000000 dead000000000122 ffff8880080718c0 raw: 0000000000000000 0000000000110011 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888017c5b300: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc ffff888017c5b380: fc fc fc fc fa fb fb fb fb fb fb fb fb fb fb fb >ffff888017c5b400: fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc ^ ffff888017c5b480: fc 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888017c5b500: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc 00 00 ================================================================== kmemleak: 166 new suspected memory leaks (see /sys/kernel/debug/kmemleak)