------------[ cut here ]------------ refcount_t: increment on 0; use-after-free. WARNING: CPU: 0 PID: 10653 at lib/refcount.c:156 refcount_inc_checked lib/refcount.c:156 [inline] WARNING: CPU: 0 PID: 10653 at lib/refcount.c:156 refcount_inc_checked+0x61/0x70 lib/refcount.c:154 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 10653 Comm: syz-executor.0 Not tainted 5.3.0-rc2+ #87 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 3e 90 64 06 31 ff 89 de e8 bb 99 35 fe 84 db 75 dd e8 72 98 35 fe 48 c7 c7 80 03 c6 87 c6 05 1e 90 64 06 01 e8 37 05 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:ffff8880ae809bf0 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000100 RSI: ffffffff815c5216 RDI: ffffed1015d01370 RBP: ffff8880ae809c00 R08: ffff88809339e200 R09: fffffbfff11b42a5 R10: fffffbfff11b42a4 R11: ffffffff88da1523 R12: ffff88808ff45440 R13: ffff88808ff45428 R14: ffff88805bc36088 R15: ffff88805bc36060 sock_hold include/net/sock.h:649 [inline] sk_add_node include/net/sock.h:701 [inline] nr_insert_socket+0x2d/0xe0 net/netrom/af_netrom.c:137 nr_rx_frame+0x1605/0x1e73 net/netrom/af_netrom.c:1023 nr_loopback_timer+0x7b/0x170 net/netrom/nr_loopback.c:59 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1322 expire_timers kernel/time/timer.c:1366 [inline] __run_timers kernel/time/timer.c:1685 [inline] __run_timers kernel/time/timer.c:1653 [inline] run_timer_softirq+0x697/0x17a0 kernel/time/timer.c:1698 __do_softirq+0x262/0x98c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:537 [inline] smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1095 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:828 RIP: 0010:__read_once_size include/linux/compiler.h:199 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:70 [inline] RIP: 0010:write_comp_data+0x17/0x70 kernel/kcov.c:123 Code: c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 5d c3 0f 1f 00 65 4c 8b 04 25 40 fe 01 00 65 8b 05 48 5e 8f 7e a9 00 01 1f 00 75 51 <41> 8b 80 f0 12 00 00 83 f8 03 75 45 49 8b 80 f8 12 00 00 45 8b 80 RSP: 0018:ffff88808f9077a8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 0000000080000002 RBX: 800000008b6dc007 RCX: ffffffff819d59ba RDX: 800000008b6dc007 RSI: 0000000000000000 RDI: 0000000000000007 RBP: ffff88808f9077b0 R08: ffff88809339e200 R09: fffff9400045a539 R10: fffff9400045a538 R11: ffffea00022d29c7 R12: 1ffff11011f20efa R13: ffff88808f907830 R14: ffff888098c05040 R15: dffffc0000000000 __pte_needs_invert arch/x86/include/asm/pgtable-invert.h:18 [inline] protnone_mask arch/x86/include/asm/pgtable-invert.h:24 [inline] pte_pfn arch/x86/include/asm/pgtable.h:214 [inline] vm_normal_page+0xda/0x3c0 mm/memory.c:577 copy_one_pte mm/memory.c:770 [inline] copy_pte_range mm/memory.c:823 [inline] copy_pmd_range mm/memory.c:874 [inline] copy_pud_range mm/memory.c:908 [inline] copy_p4d_range mm/memory.c:930 [inline] copy_page_range+0xb37/0x1ee0 mm/memory.c:992 dup_mmap kernel/fork.c:592 [inline] dup_mm+0xa67/0x1430 kernel/fork.c:1346 copy_mm kernel/fork.c:1402 [inline] copy_process+0x28b7/0x6b00 kernel/fork.c:2017 _do_fork+0x146/0xfa0 kernel/fork.c:2369 __do_sys_clone kernel/fork.c:2524 [inline] __se_sys_clone kernel/fork.c:2505 [inline] __x64_sys_clone+0x18d/0x250 kernel/fork.c:2505 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457dfa Code: f7 d8 64 89 04 25 d4 02 00 00 64 4c 8b 0c 25 10 00 00 00 31 d2 4d 8d 91 d0 02 00 00 31 f6 bf 11 00 20 01 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 f5 00 00 00 85 c0 41 89 c5 0f 85 fc 00 00 RSP: 002b:00007ffc4f350d80 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffc4f350d80 RCX: 0000000000457dfa RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007ffc4f350dc0 R08: 0000000000000001 R09: 0000555555f43940 R10: 0000555555f43c10 R11: 0000000000000246 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffc4f350e10 Kernel Offset: disabled Rebooting in 86400 seconds..