------------[ cut here ]------------ refcount_t: increment on 0; use-after-free. WARNING: CPU: 1 PID: 15456 at lib/refcount.c:156 refcount_inc_checked lib/refcount.c:156 [inline] WARNING: CPU: 1 PID: 15456 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: 15456 Comm: syz-executor.5 Not tainted 5.4.0-rc7+ #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+0x197/0x210 lib/dump_stack.c:118 panic+0x2e3/0x75c kernel/panic.c:221 __warn.cold+0x2f/0x35 kernel/panic.c:582 report_bug+0x289/0x300 lib/bug.c:195 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:1028 RIP: 0010:refcount_inc_checked lib/refcount.c:156 [inline] RIP: 0010:refcount_inc_checked+0x61/0x70 lib/refcount.c:154 Code: 1d 00 d5 7d 06 31 ff 89 de e8 0b 96 2e fe 84 db 75 dd e8 c2 94 2e fe 48 c7 c7 00 ba e6 87 c6 05 e0 d4 7d 06 01 e8 d7 c7 ff fd <0f> 0b eb c1 90 90 90 90 90 90 90 90 90 90 90 55 48 89 e5 41 57 41 RSP: 0018:ffff888057a878a0 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000014759 RSI: ffffffff815cf766 RDI: ffffed100af50f06 RBP: ffff888057a878b0 R08: ffff8880a3e72580 R09: fffffbfff14f0140 R10: fffffbfff14f013f R11: ffffffff8a7809ff R12: ffff8880920d1640 R13: 0000000000000000 R14: ffff888099010040 R15: ffff888091ec0f28 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+0x4e6/0x1380 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3408 [inline] path_openat+0x10e9/0x46d0 fs/namei.c:3525 do_filp_open+0x1a1/0x280 fs/namei.c:3555 do_sys_open+0x3fe/0x5d0 fs/open.c:1097 __do_compat_sys_open fs/open.c:1134 [inline] __se_compat_sys_open fs/open.c:1132 [inline] __ia32_compat_sys_open+0x79/0xb0 fs/open.c:1132 do_syscall_32_irqs_on arch/x86/entry/common.c:333 [inline] do_fast_syscall_32+0x27b/0xdb3 arch/x86/entry/common.c:404 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7fefa39 Code: 00 00 00 89 d3 5b 5e 5f 5d c3 b8 80 96 98 00 eb c4 8b 04 24 c3 8b 1c 24 c3 8b 34 24 c3 8b 3c 24 c3 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:00000000f5deac14 EFLAGS: 00000296 ORIG_RAX: 0000000000000005 RAX: ffffffffffffffda RBX: 00000000f5deaccc RCX: 0000000000000000 RDX: 0000000000000000 RSI: 00000000f5deaccc RDI: 0000000000000000 RBP: 00000000f5deb168 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Kernel Offset: disabled Rebooting in 86400 seconds..