ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 ------------[ cut here ]------------ kernel BUG at mm/filemap.c:867! Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI CPU: 1 UID: 0 PID: 23150 Comm: syz.1.4428 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:__filemap_add_folio+0xf5b/0x11e0 mm/filemap.c:867 Code: 70 c9 ff 48 c7 c6 60 1b b9 8b 4c 89 ef e8 9d 28 11 00 90 0f 0b e8 95 70 c9 ff 48 c7 c6 c0 1b b9 8b 4c 89 ef e8 86 28 11 00 90 <0f> 0b e8 7e 70 c9 ff 90 0f 0b 90 e9 f2 fb ff ff e8 70 70 c9 ff 48 RSP: 0018:ffffc90004a4f450 EFLAGS: 00010246 RAX: 0000000000080000 RBX: 0000000000000000 RCX: ffffc9000b589000 RDX: 0000000000080000 RSI: ffffffff81f2200a RDI: ffff88807e03de44 RBP: 0000000000112cc0 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 30376478302f3165 R12: 0000000000000004 R13: ffffea0001331800 R14: 0000000000000000 R15: 0000000000000030 FS: 00007f1e4e9846c0(0000) GS:ffff8881247bd000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000001a40 CR3: 000000004f6a0000 CR4: 0000000000350ef0 Call Trace: filemap_add_folio+0x10e/0x220 mm/filemap.c:969 ra_alloc_folio mm/readahead.c:448 [inline] page_cache_ra_order+0x5a7/0xd70 mm/readahead.c:506 do_sync_mmap_readahead mm/filemap.c:3304 [inline] filemap_fault+0x152e/0x2930 mm/filemap.c:3445 __do_fault+0x10d/0x490 mm/memory.c:5152 do_shared_fault mm/memory.c:5637 [inline] do_fault mm/memory.c:5711 [inline] do_pte_missing+0x1a6/0x3ba0 mm/memory.c:4234 handle_pte_fault mm/memory.c:6052 [inline] __handle_mm_fault+0x152a/0x2a50 mm/memory.c:6195 handle_mm_fault+0x589/0xd10 mm/memory.c:6364 do_user_addr_fault+0x7a6/0x1370 arch/x86/mm/fault.c:1387 handle_page_fault arch/x86/mm/fault.c:1476 [inline] exc_page_fault+0x5c/0xb0 arch/x86/mm/fault.c:1532 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0010:copy_user_generic arch/x86/include/asm/uaccess_64.h:126 [inline] RIP: 0010:raw_copy_to_user arch/x86/include/asm/uaccess_64.h:147 [inline] RIP: 0010:_inline_copy_to_user include/linux/uaccess.h:197 [inline] RIP: 0010:_copy_to_user+0xb6/0xd0 lib/usercopy.c:26 Code: 89 ee 48 89 ef e8 ba e5 d9 fc 4d 85 ff 75 a8 e8 00 eb d9 fc 89 de 4c 89 e7 e8 66 53 3f fd 0f 01 cb 48 89 d9 48 89 ef 4c 89 e6 a4 0f 1f 00 0f 01 ca 48 89 cb eb 80 66 2e 0f 1f 84 00 00 00 00 RSP: 0018:ffffc90004a4fc40 EFLAGS: 00050246 RAX: 0000000000000001 RBX: 0000000000000008 RCX: 0000000000000008 RDX: fffff52000949f97 RSI: ffffc90004a4fcb0 RDI: 0000200000030000 RBP: 0000200000030000 R08: 0000000000000000 R09: fffff52000949f96 R10: ffffc90004a4fcb7 R11: 0000000000000001 R12: ffffc90004a4fcb0 R13: 0000200000030008 R14: 00007ffffffff000 R15: 0000000000000000 copy_to_user include/linux/uaccess.h:225 [inline] msr_read+0x14e/0x250 arch/x86/kernel/msr.c:69 vfs_read+0x1e4/0xcf0 fs/read_write.c:570 ksys_read+0x12a/0x250 fs/read_write.c:715 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1e4db8ebe9 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:00007f1e4e984038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007f1e4ddb5fa0 RCX: 00007f1e4db8ebe9 RDX: 0000000000018ff8 RSI: 0000200000019680 RDI: 0000000000000005 RBP: 00007f1e4dc11e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1e4ddb6038 R14: 00007f1e4ddb5fa0 R15: 00007ffe3cbcfd48 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:__filemap_add_folio+0xf5b/0x11e0 mm/filemap.c:867 Code: 70 c9 ff 48 c7 c6 60 1b b9 8b 4c 89 ef e8 9d 28 11 00 90 0f 0b e8 95 70 c9 ff 48 c7 c6 c0 1b b9 8b 4c 89 ef e8 86 28 11 00 90 <0f> 0b e8 7e 70 c9 ff 90 0f 0b 90 e9 f2 fb ff ff e8 70 70 c9 ff 48 RSP: 0018:ffffc90004a4f450 EFLAGS: 00010246 RAX: 0000000000080000 RBX: 0000000000000000 RCX: ffffc9000b589000 RDX: 0000000000080000 RSI: ffffffff81f2200a RDI: ffff88807e03de44 RBP: 0000000000112cc0 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 30376478302f3165 R12: 0000000000000004 R13: ffffea0001331800 R14: 0000000000000000 R15: 0000000000000030 FS: 00007f1e4e9846c0(0000) GS:ffff8881247bd000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000001a40 CR3: 000000004f6a0000 CR4: 0000000000350ef0 ---------------- Code disassembly (best guess): 0: 89 ee mov %ebp,%esi 2: 48 89 ef mov %rbp,%rdi 5: e8 ba e5 d9 fc call 0xfcd9e5c4 a: 4d 85 ff test %r15,%r15 d: 75 a8 jne 0xffffffb7 f: e8 00 eb d9 fc call 0xfcd9eb14 14: 89 de mov %ebx,%esi 16: 4c 89 e7 mov %r12,%rdi 19: e8 66 53 3f fd call 0xfd3f5384 1e: 0f 01 cb stac 21: 48 89 d9 mov %rbx,%rcx 24: 48 89 ef mov %rbp,%rdi 27: 4c 89 e6 mov %r12,%rsi * 2a: f3 a4 rep movsb %ds:(%rsi),%es:(%rdi) <-- trapping instruction 2c: 0f 1f 00 nopl (%rax) 2f: 0f 01 ca clac 32: 48 89 cb mov %rcx,%rbx 35: eb 80 jmp 0xffffffb7 37: 66 data16 38: 2e cs 39: 0f .byte 0xf 3a: 1f (bad) 3b: 84 00 test %al,(%rax) 3d: 00 00 add %al,(%rax)