------------[ cut here ]------------ refcount_t: increment on 0; use-after-free. WARNING: CPU: 1 PID: 18107 at lib/refcount.c:156 refcount_inc_checked lib/refcount.c:156 [inline] WARNING: CPU: 1 PID: 18107 at lib/refcount.c:156 refcount_inc_checked+0x61/0x70 lib/refcount.c:154 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 18107 Comm: syz-executor.1 Not tainted 5.3.0-rc2+ #83 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+0x172/0x1f0 lib/dump_stack.c:113 panic+0x2dc/0x755 kernel/panic.c:219 __warn.cold+0x20/0x4c kernel/panic.c:576 report_bug+0x263/0x2b0 lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:179 [inline] fixup_bug arch/x86/kernel/traps.c:174 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:272 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:291 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1026 RIP: 0010:refcount_inc_checked lib/refcount.c:156 [inline] RIP: 0010:refcount_inc_checked+0x61/0x70 lib/refcount.c:154 Code: 1d fe 8f 64 06 31 ff 89 de e8 4b 99 35 fe 84 db 75 dd e8 02 98 35 fe 48 c7 c7 80 03 c6 87 c6 05 de 8f 64 06 01 e8 b7 04 07 fe <0f> 0b eb c1 90 90 90 90 90 90 90 90 90 90 90 55 48 89 e5 41 57 41 RSP: 0018:ffff8880592c78a8 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 00000000000197ea RSI: ffffffff815c5216 RDI: ffffed100b258f07 RBP: ffff8880592c78b8 R08: ffff88808e170180 R09: fffffbfff134ada8 R10: fffffbfff134ada7 R11: ffffffff89a56d3f R12: ffff888068c52640 R13: 0000000000000000 R14: ffff888099f99780 R15: ffff888095f8a9e8 kref_get include/linux/kref.h:45 [inline] kobject_get+0x66/0xc0 lib/kobject.c:644 cdev_get+0x60/0xb0 fs/char_dev.c:355 chrdev_open+0xb0/0x6b0 fs/char_dev.c:400 do_dentry_open+0x4df/0x1250 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:906 do_last fs/namei.c:3416 [inline] path_openat+0x10e9/0x4630 fs/namei.c:3533 do_filp_open+0x1a1/0x280 fs/namei.c:3563 do_sys_open+0x3fe/0x5d0 fs/open.c:1089 __do_compat_sys_open fs/open.c:1126 [inline] __se_compat_sys_open fs/open.c:1124 [inline] __ia32_compat_sys_open+0x79/0xb0 fs/open.c:1124 do_syscall_32_irqs_on arch/x86/entry/common.c:332 [inline] do_fast_syscall_32+0x27b/0xdb3 arch/x86/entry/common.c:403 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7fac9c9 Code: d3 83 c4 10 5b 5e 5d c3 ba 80 96 98 00 eb a9 8b 04 24 c3 8b 34 24 c3 8b 3c 24 c3 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 002b:00000000f5d86c14 EFLAGS: 00000296 ORIG_RAX: 0000000000000005 RAX: ffffffffffffffda RBX: 00000000f5d86ccc RCX: 0000000000000000 RDX: 0000000000000000 RSI: 00000000f5d86ccc RDI: 0000000000000000 RBP: 00000000f5d87168 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Kernel Offset: disabled Rebooting in 86400 seconds..