BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0010) - not-present page PGD 1d7fd9067 P4D 1d7fd9067 PUD 0 Oops: 0010 [#1] PREEMPT SMP KASAN CPU: 0 PID: 2936 Comm: syz.3.663 Not tainted 5.4.292-syzkaller-00021-gcd8e74fa0fa3 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:0x0 Code: Bad RIP value. RSP: 0018:ffff8881f6e09cf0 EFLAGS: 00010206 RAX: ffffffff8150a590 RBX: 0000000000000100 RCX: ffff8881ebbbcec0 RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff8881ea79b1c0 RBP: ffff8881f6e09d30 R08: 0000000000000004 R09: 0000000000000003 R10: ffffed103edc1398 R11: 1ffff1103edc1398 R12: 00000000ffffb9b8 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881ea79b1c0 FS: 00007fd491aab6c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 00000001c568d000 CR4: 00000000003406b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: call_timer_fn+0x3c/0x380 kernel/time/timer.c:1448 expire_timers kernel/time/timer.c:1493 [inline] __run_timers+0x81d/0xb60 kernel/time/timer.c:1817 run_timer_softirq+0x6a/0xf0 kernel/time/timer.c:1830 __do_softirq+0x236/0x660 kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x197/0x1c0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:539 [inline] smp_apic_timer_interrupt+0x11d/0x490 arch/x86/kernel/apic/apic.c:1161 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:834 RIP: 0010:compound_head include/linux/page-flags.h:176 [inline] RIP: 0010:PageSwapCache include/linux/page-flags.h:383 [inline] RIP: 0010:free_swap_cache+0x3d/0x230 mm/swap_state.c:268 Code: 00 00 00 00 fc ff df e8 11 57 d4 ff 4c 8d 6b 08 4d 89 ee 49 c1 ee 03 43 80 3c 3e 00 74 08 4c 89 ef e8 27 51 02 00 4d 8b 7d 00 <44> 89 fe 83 e6 01 31 ff e8 b6 5a d4 ff 41 f6 c7 01 0f 85 a8 01 00 RSP: 0018:ffff8881e54b7568 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffffffff818b27cf RBX: ffffea0007955d40 RCX: ffff8881ebbbcec0 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffea0007955d40 RBP: ffff8881e54b7590 R08: dffffc0000000000 R09: fffff94000eaf2f1 R10: fffff94000eaf2f1 R11: 1ffffd4000eaf2f0 R12: 0000000000000d50 R13: ffffea0007955d48 R14: 1ffffd4000f2aba9 R15: dead000000000100 free_pages_and_swap_cache+0x60/0xa0 mm/swap_state.c:296 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline] tlb_flush_mmu_free mm/mmu_gather.c:189 [inline] tlb_flush_mmu+0xd6/0x180 mm/mmu_gather.c:196 zap_pte_range mm/memory.c:1173 [inline] zap_pmd_range mm/memory.c:1222 [inline] zap_pud_range mm/memory.c:1251 [inline] zap_p4d_range mm/memory.c:1272 [inline] unmap_page_range+0x1968/0x1b20 mm/memory.c:1293 unmap_single_vma mm/memory.c:1338 [inline] unmap_vmas+0x245/0x340 mm/memory.c:1370 exit_mmap+0x2bb/0x520 mm/mmap.c:3191 __mmput+0x92/0x2e0 kernel/fork.c:1101 mmput+0x47/0x60 kernel/fork.c:1122 exit_mm kernel/exit.c:538 [inline] do_exit+0x99f/0x2660 kernel/exit.c:848 do_group_exit+0x13e/0x300 kernel/exit.c:984 get_signal+0xdee/0x13d0 kernel/signal.c:2738 do_signal+0xad/0xda0 arch/x86/kernel/signal.c:809 exit_to_usermode_loop+0xc4/0x1b0 arch/x86/entry/common.c:159 prepare_exit_to_usermode+0x18e/0x1f0 arch/x86/entry/common.c:194 syscall_return_slowpath arch/x86/entry/common.c:274 [inline] do_syscall_64+0x13e/0x170 arch/x86/entry/common.c:300 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 RIP: 0033:0x7fd493442969 Code: Bad RIP value. RSP: 002b:00007fd491aab038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: fffffffffffffff5 RBX: 00007fd493669fa0 RCX: 00007fd493442969 RDX: 0000000000000048 RSI: 000020000000e000 RDI: 0000000000000005 RBP: 00007fd4934c4ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fd493669fa0 R15: 00007ffefc6d1168 Modules linked in: CR2: 0000000000000000 ---[ end trace 9ba6ae8a00d69c9e ]--- RIP: 0010:0x0 Code: Bad RIP value. RSP: 0018:ffff8881f6e09cf0 EFLAGS: 00010206 RAX: ffffffff8150a590 RBX: 0000000000000100 RCX: ffff8881ebbbcec0 RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff8881ea79b1c0 RBP: ffff8881f6e09d30 R08: 0000000000000004 R09: 0000000000000003 R10: ffffed103edc1398 R11: 1ffff1103edc1398 R12: 00000000ffffb9b8 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881ea79b1c0 FS: 00007fd491aab6c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 00000001c568d000 CR4: 00000000003406b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 ---------------- Code disassembly (best guess), 6 bytes skipped: 0: df e8 fucomip %st(0),%st 2: 11 57 d4 adc %edx,-0x2c(%rdi) 5: ff 4c 8d 6b decl 0x6b(%rbp,%rcx,4) 9: 08 4d 89 or %cl,-0x77(%rbp) c: ee out %al,(%dx) d: 49 c1 ee 03 shr $0x3,%r14 11: 43 80 3c 3e 00 cmpb $0x0,(%r14,%r15,1) 16: 74 08 je 0x20 18: 4c 89 ef mov %r13,%rdi 1b: e8 27 51 02 00 call 0x25147 20: 4d 8b 7d 00 mov 0x0(%r13),%r15 * 24: 44 89 fe mov %r15d,%esi <-- trapping instruction 27: 83 e6 01 and $0x1,%esi 2a: 31 ff xor %edi,%edi 2c: e8 b6 5a d4 ff call 0xffd45ae7 31: 41 f6 c7 01 test $0x1,%r15b 35: 0f .byte 0xf 36: 85 .byte 0x85 37: a8 01 test $0x1,%al