Hello, syzbot found the following issue on: HEAD commit: df5d6180169a Add linux-next specific files for 20250210 git tree: linux-next console+strace: https://syzkaller.appspot.com/x/log.txt?x=16d343f8580000 kernel config: https://syzkaller.appspot.com/x/.config?x=2cd616b6e736ca7 dashboard link: https://syzkaller.appspot.com/bug?extid=012c6245eaea0e23f7f9 compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=138972a4580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11737b18580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/92495cf20271/disk-df5d6180.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/4b3656161842/vmlinux-df5d6180.xz kernel image: https://storage.googleapis.com/syzbot-assets/7fbc4e7a0f5d/bzImage-df5d6180.xz The issue was bisected to: commit 19c067c8a0f18b62d4a4235b0b327624c86f2e40 Author: Zi Yan <ziy@xxxxxxxxxx> Date: Wed Feb 5 03:14:13 2025 +0000 mm/huge_memory: add buddy allocator like folio_split() bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=102f9bdf980000 final oops: https://syzkaller.appspot.com/x/report.txt?x=122f9bdf980000 console output: https://syzkaller.appspot.com/x/log.txt?x=142f9bdf980000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+012c6245eaea0e23f7f9@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: 19c067c8a0f1 ("mm/huge_memory: add buddy allocator like folio_split()") Oops: general protection fault, probably for non-canonical address 0xdffffc0000000024: 0000 [#1] PREEMPT SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000120-0x0000000000000127] CPU: 1 UID: 0 PID: 5949 Comm: syz-executor163 Not tainted 6.14.0-rc2-next-20250210-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 RIP: 0010:shmem_mapping+0x25/0x50 mm/shmem.c:281 Code: 90 90 90 90 90 f3 0f 1e fa 53 48 89 fb e8 c3 3a bd ff 48 81 c3 20 01 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 dd 35 24 00 48 c7 c0 80 6c 14 8c 48 RSP: 0018:ffffc90004036dd8 EFLAGS: 00010006 RAX: 0000000000000024 RBX: 0000000000000120 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000000600 RDI: 0000000000000000 RBP: 0000000000000600 R08: ffffffff822bcf18 R09: 1ffffd4000331008 R10: dffffc0000000000 R11: fffff94000331009 R12: ffffea0001988018 R13: ffffea0001988080 R14: ffffea0001988018 R15: ffffea0001988000 FS: 00007f5e045316c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5e0458dae0 CR3: 0000000023c78000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> __split_unmapped_folio+0x238a/0x3e50 mm/huge_memory.c:3587 __folio_split+0x1267/0x16d0 mm/huge_memory.c:3871 try_folio_split include/linux/huge_mm.h:374 [inline] truncate_inode_partial_folio+0x55d/0xdc0 mm/truncate.c:230 shmem_undo_range+0xab7/0x1820 mm/shmem.c:1144 shmem_truncate_range mm/shmem.c:1224 [inline] shmem_fallocate+0x431/0xf20 mm/shmem.c:3674 vfs_fallocate+0x623/0x7a0 fs/open.c:338 madvise_remove mm/madvise.c:1034 [inline] madvise_vma_behavior mm/madvise.c:1269 [inline] madvise_walk_vmas mm/madvise.c:1511 [inline] madvise_do_behavior+0x1f29/0x3c00 mm/madvise.c:1646 do_madvise mm/madvise.c:1744 [inline] __do_sys_madvise mm/madvise.c:1752 [inline] __se_sys_madvise mm/madvise.c:1750 [inline] __x64_sys_madvise+0x11b/0x140 mm/madvise.c:1750 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5e04576519 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 18 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f5e04531218 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 00007f5e04600308 RCX: 00007f5e04576519 RDX: 0000000000000009 RSI: 0000000000600003 RDI: 0000400000000000 RBP: 00007f5e04600300 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5e045cd074 R13: 0000400000000000 R14: 0000400000000140 R15: 0000400000000040 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:shmem_mapping+0x25/0x50 mm/shmem.c:281 Code: 90 90 90 90 90 f3 0f 1e fa 53 48 89 fb e8 c3 3a bd ff 48 81 c3 20 01 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 dd 35 24 00 48 c7 c0 80 6c 14 8c 48 RSP: 0018:ffffc90004036dd8 EFLAGS: 00010006 RAX: 0000000000000024 RBX: 0000000000000120 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000000600 RDI: 0000000000000000 RBP: 0000000000000600 R08: ffffffff822bcf18 R09: 1ffffd4000331008 R10: dffffc0000000000 R11: fffff94000331009 R12: ffffea0001988018 R13: ffffea0001988080 R14: ffffea0001988018 R15: ffffea0001988000 FS: 00007f5e045316c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5e0458dae0 CR3: 0000000023c78000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 90 nop 1: 90 nop 2: 90 nop 3: 90 nop 4: 90 nop 5: f3 0f 1e fa endbr64 9: 53 push %rbx a: 48 89 fb mov %rdi,%rbx d: e8 c3 3a bd ff call 0xffbd3ad5 12: 48 81 c3 20 01 00 00 add $0x120,%rbx 19: 48 89 d8 mov %rbx,%rax 1c: 48 c1 e8 03 shr $0x3,%rax 20: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx 27: fc ff df * 2a: 80 3c 08 00 cmpb $0x0,(%rax,%rcx,1) <-- trapping instruction 2e: 74 08 je 0x38 30: 48 89 df mov %rbx,%rdi 33: e8 dd 35 24 00 call 0x243615 38: 48 c7 c0 80 6c 14 8c mov $0xffffffff8c146c80,%rax 3f: 48 rex.W --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. For information about bisection process see: https://goo.gl/tpsmEJ#bisection If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
