general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 0 PID: 23891 Comm: syz.4.5855 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:f2fs_test_and_set_bit fs/f2fs/f2fs.h:2952 [inline] RIP: 0010:update_sit_entry_for_alloc fs/f2fs/segment.c:2396 [inline] RIP: 0010:update_sit_entry+0x4f9/0x15a0 fs/f2fs/segment.c:2440 Code: 00 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 7e e3 8c ff 48 8b 1b 4c 01 f3 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <0f> b6 04 08 84 c0 0f 85 55 0f 00 00 44 0f b6 23 44 89 e0 44 08 f8 RSP: 0000:ffffc9001095e700 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: dffffc0000000000 RDX: ffff88814a805100 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9001095e7d0 R08: ffff88814a805100 R09: 0000000000000003 R10: 00000000ffffffff R11: 0000000000000000 R12: 0000000000000000 R13: ffff88816f7a80c8 R14: 0000000000000000 R15: 0000000000000004 FS: 00007f27e09686c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00001fffffffff00 CR3: 000000018a8f4000 CR4: 00000000003506b0 DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083 DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: f2fs_allocate_data_block+0x148c/0x3af0 fs/f2fs/segment.c:3430 do_write_page+0x297/0xc40 fs/f2fs/segment.c:3532 f2fs_outplace_write_data+0x14f/0x2d0 fs/f2fs/segment.c:3605 f2fs_convert_inline_page+0x6ff/0xe90 fs/f2fs/inline.c:179 f2fs_convert_inline_inode+0x873/0x960 fs/f2fs/inline.c:231 f2fs_preallocate_blocks fs/f2fs/file.c:4689 [inline] f2fs_file_write_iter+0x11b4/0x2550 fs/f2fs/file.c:4935 __kernel_write_iter+0x27e/0x640 fs/read_write.c:517 __kernel_write+0xec/0x140 fs/read_write.c:537 __dump_emit+0x1ff/0x300 fs/coredump.c:809 dump_emit+0xa8/0xc0 fs/coredump.c:846 writenote+0x1bb/0x2e0 fs/binfmt_elf.c:1530 write_note_info fs/binfmt_elf.c:1998 [inline] elf_core_dump+0x268b/0x2ef0 fs/binfmt_elf.c:2341 do_coredump+0x1557/0x21b0 fs/coredump.c:760 get_signal+0x11db/0x1520 kernel/signal.c:2875 arch_do_signal_or_restart+0xb0/0x1030 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x7a/0xb0 kernel/entry/common.c:174 exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:210 irqentry_exit_to_user_mode+0x9/0x10 kernel/entry/common.c:316 irqentry_exit+0x12/0x40 kernel/entry/common.c:419 exc_general_protection+0x14e/0x1e0 arch/x86/kernel/traps.c:729 asm_exc_general_protection+0x27/0x30 arch/x86/include/asm/idtentry.h:602 RIP: 0033:0x7f27dfb8f751 Code: 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 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f RSP: 002b:00002000000002f0 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00007f27dfde5fa0 RCX: 00007f27dfb8f749 RDX: 0000200000000100 RSI: 00002000000002f0 RDI: 0000000000040000 RBP: 00007f27dfc13f91 R08: 0000200000000480 R09: 0000200000000480 R10: 0000200000000340 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f27dfde6038 R14: 00007f27dfde5fa0 R15: 00007ffd67ed9718 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:f2fs_test_and_set_bit fs/f2fs/f2fs.h:2952 [inline] RIP: 0010:update_sit_entry_for_alloc fs/f2fs/segment.c:2396 [inline] RIP: 0010:update_sit_entry+0x4f9/0x15a0 fs/f2fs/segment.c:2440 Code: 00 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 7e e3 8c ff 48 8b 1b 4c 01 f3 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <0f> b6 04 08 84 c0 0f 85 55 0f 00 00 44 0f b6 23 44 89 e0 44 08 f8 RSP: 0000:ffffc9001095e700 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: dffffc0000000000 RDX: ffff88814a805100 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9001095e7d0 R08: ffff88814a805100 R09: 0000000000000003 R10: 00000000ffffffff R11: 0000000000000000 R12: 0000000000000000 R13: ffff88816f7a80c8 R14: 0000000000000000 R15: 0000000000000004 FS: 00007f27e09686c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000e0000001d CR3: 000000018a8f4000 CR4: 00000000003506b0 DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083 DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess), 4 bytes skipped: 0: df 80 3c 08 00 74 filds 0x7400083c(%rax) 6: 08 48 89 or %cl,-0x77(%rax) 9: df e8 fucomip %st(0),%st b: 7e e3 jle 0xfffffff0 d: 8c ff mov %?,%edi f: 48 8b 1b mov (%rbx),%rbx 12: 4c 01 f3 add %r14,%rbx 15: 48 89 d8 mov %rbx,%rax 18: 48 c1 e8 03 shr $0x3,%rax 1c: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx 23: fc ff df * 26: 0f b6 04 08 movzbl (%rax,%rcx,1),%eax <-- trapping instruction 2a: 84 c0 test %al,%al 2c: 0f 85 55 0f 00 00 jne 0xf87 32: 44 0f b6 23 movzbl (%rbx),%r12d 36: 44 89 e0 mov %r12d,%eax 39: 44 08 f8 or %r15b,%al