================================================================== BUG: KASAN: null-ptr-deref in atomic_inc include/asm-generic/atomic-instrumented.h:239 [inline] BUG: KASAN: null-ptr-deref in __remove_shared_vm_struct mm/mmap.c:144 [inline] BUG: KASAN: null-ptr-deref in unlink_file_vma+0x12d/0x1b0 mm/mmap.c:164 Write of size 4 at addr 0000000000000168 by task syz.6.329/1490 CPU: 0 PID: 1490 Comm: syz.6.329 Not tainted 5.4.290-syzkaller-00017-g6b07fcd94a6a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1d8/0x241 lib/dump_stack.c:118 __kasan_report+0xe9/0x120 mm/kasan/report.c:520 kasan_report+0x30/0x60 mm/kasan/common.c:653 check_memory_region_inline mm/kasan/generic.c:141 [inline] check_memory_region+0x272/0x280 mm/kasan/generic.c:191 atomic_inc include/asm-generic/atomic-instrumented.h:239 [inline] __remove_shared_vm_struct mm/mmap.c:144 [inline] unlink_file_vma+0x12d/0x1b0 mm/mmap.c:164 free_pgtables+0x135/0x280 mm/memory.c:428 exit_mmap+0x2cb/0x520 mm/mmap.c:3192 __mmput+0x8e/0x2c0 kernel/fork.c:1101 exit_mm kernel/exit.c:538 [inline] do_exit+0xc08/0x2bc0 kernel/exit.c:848 do_group_exit+0x138/0x300 kernel/exit.c:984 get_signal+0xdb1/0x1440 kernel/signal.c:2738 do_signal+0xb0/0x11f0 arch/x86/kernel/signal.c:809 exit_to_usermode_loop+0xc0/0x1a0 arch/x86/entry/common.c:159 prepare_exit_to_usermode+0x199/0x200 arch/x86/entry/common.c:194 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 RIP: 0033:0x7fe7ad366169 Code: Bad RIP value. RSP: 002b:00007fe7ab9d00e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fe7ad57efa8 RCX: 00007fe7ad366169 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fe7ad57efa8 RBP: 00007fe7ad57efa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe7ad57efac R13: 0000000000000000 R14: 00007fff6638cda0 R15: 00007fff6638ce88 ================================================================== BUG: kernel NULL pointer dereference, address: 0000000000000168 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 1d6a63067 P4D 1d6a63067 PUD 0 Oops: 0002 [#1] PREEMPT SMP KASAN CPU: 0 PID: 1490 Comm: syz.6.329 Tainted: G B 5.4.290-syzkaller-00017-g6b07fcd94a6a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:arch_atomic_inc arch/x86/include/asm/atomic.h:97 [inline] RIP: 0010:atomic_inc include/asm-generic/atomic-instrumented.h:240 [inline] RIP: 0010:__remove_shared_vm_struct mm/mmap.c:144 [inline] RIP: 0010:unlink_file_vma+0x12d/0x1b0 mm/mmap.c:164 Code: 00 00 00 fc ff df 42 80 3c 38 00 74 08 4c 89 e7 e8 28 c5 07 00 49 8b 2c 24 48 8d bd 68 01 00 00 be 04 00 00 00 e8 83 98 07 00 ff 85 68 01 00 00 4c 8b 74 24 10 48 8b 2c 24 43 80 7c 3d 00 00 RSP: 0018:ffff8881da887818 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8881e630f178 RCX: ffff8881e8856e40 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00000000ffffffff RBP: 0000000000000000 R08: ffffffff813ae545 R09: 0000000000000003 R10: ffffffffffffffff R11: dffffc0000000001 R12: ffff8881f6e49788 R13: 1ffff1103cc61e2f R14: 0000000000100871 R15: dffffc0000000000 FS: 00007fe7ab9d06c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000168 CR3: 00000001e4c00000 CR4: 00000000003406b0 DR0: 0000400000000300 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: free_pgtables+0x135/0x280 mm/memory.c:428 exit_mmap+0x2cb/0x520 mm/mmap.c:3192 __mmput+0x8e/0x2c0 kernel/fork.c:1101 exit_mm kernel/exit.c:538 [inline] do_exit+0xc08/0x2bc0 kernel/exit.c:848 do_group_exit+0x138/0x300 kernel/exit.c:984 get_signal+0xdb1/0x1440 kernel/signal.c:2738 do_signal+0xb0/0x11f0 arch/x86/kernel/signal.c:809 exit_to_usermode_loop+0xc0/0x1a0 arch/x86/entry/common.c:159 prepare_exit_to_usermode+0x199/0x200 arch/x86/entry/common.c:194 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 RIP: 0033:0x7fe7ad366169 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fe7ab9d00e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fe7ad57efa8 RCX: 00007fe7ad366169 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fe7ad57efa8 RBP: 00007fe7ad57efa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe7ad57efac R13: 0000000000000000 R14: 00007fff6638cda0 R15: 00007fff6638ce88 Modules linked in: CR2: 0000000000000168 ---[ end trace e79df92a8f0c004a ]--- RIP: 0010:arch_atomic_inc arch/x86/include/asm/atomic.h:97 [inline] RIP: 0010:atomic_inc include/asm-generic/atomic-instrumented.h:240 [inline] RIP: 0010:__remove_shared_vm_struct mm/mmap.c:144 [inline] RIP: 0010:unlink_file_vma+0x12d/0x1b0 mm/mmap.c:164 Code: 00 00 00 fc ff df 42 80 3c 38 00 74 08 4c 89 e7 e8 28 c5 07 00 49 8b 2c 24 48 8d bd 68 01 00 00 be 04 00 00 00 e8 83 98 07 00 ff 85 68 01 00 00 4c 8b 74 24 10 48 8b 2c 24 43 80 7c 3d 00 00 RSP: 0018:ffff8881da887818 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8881e630f178 RCX: ffff8881e8856e40 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00000000ffffffff RBP: 0000000000000000 R08: ffffffff813ae545 R09: 0000000000000003 R10: ffffffffffffffff R11: dffffc0000000001 R12: ffff8881f6e49788 R13: 1ffff1103cc61e2f R14: 0000000000100871 R15: dffffc0000000000 FS: 00007fe7ab9d06c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000168 CR3: 00000001e4c00000 CR4: 00000000003406b0 DR0: 0000400000000300 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 ---------------- Code disassembly (best guess), 5 bytes skipped: 0: df 42 80 filds -0x80(%rdx) 3: 3c 38 cmp $0x38,%al 5: 00 74 08 4c add %dh,0x4c(%rax,%rcx,1) 9: 89 e7 mov %esp,%edi b: e8 28 c5 07 00 call 0x7c538 10: 49 8b 2c 24 mov (%r12),%rbp 14: 48 8d bd 68 01 00 00 lea 0x168(%rbp),%rdi 1b: be 04 00 00 00 mov $0x4,%esi 20: e8 83 98 07 00 call 0x798a8 * 25: f0 ff 85 68 01 00 00 lock incl 0x168(%rbp) <-- trapping instruction 2c: 4c 8b 74 24 10 mov 0x10(%rsp),%r14 31: 48 8b 2c 24 mov (%rsp),%rbp 35: 43 80 7c 3d 00 00 cmpb $0x0,0x0(%r13,%r15,1)