Hello, syzbot found the following issue on: HEAD commit: 8a749fd1a872 Linux 6.6-rc4 git tree: upstream console+strace: https://syzkaller.appspot.com/x/log.txt?x=154d1e92680000 kernel config: https://syzkaller.appspot.com/x/.config?x=57da1ac039c4c78a dashboard link: https://syzkaller.appspot.com/bug?extid=2208f82282740c1c8915 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=14877eb2680000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13b701f6680000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/fffd72e2263d/disk-8a749fd1.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/0645b67d82dc/vmlinux-8a749fd1.xz kernel image: https://storage.googleapis.com/syzbot-assets/135b10b98a67/bzImage-8a749fd1.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+2208f82282740c1c8915@xxxxxxxxxxxxxxxxxxxxxxxxx general protection fault, probably for non-canonical address 0xdffffc000000001c: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x00000000000000e0-0x00000000000000e7] CPU: 1 PID: 5028 Comm: syz-executor194 Not tainted 6.6.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023 RIP: 0010:ovl_encode_real_fh+0x87/0x400 fs/overlayfs/copy_up.c:380 Code: 20 49 c1 ee 03 48 b8 f1 f1 f1 f1 04 f3 f3 f3 49 89 04 1e e8 1b e5 8b fe 48 89 d9 49 8d 9c 24 e0 00 00 00 48 89 d8 48 c1 e8 03 <80> 3c 08 00 74 12 48 89 df e8 0b 61 e6 fe 48 b9 00 00 00 00 00 fc RSP: 0018:ffffc900039efc80 EFLAGS: 00010202 RAX: 000000000000001c RBX: 00000000000000e0 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8880132ab500 RBP: ffffc900039efd30 R08: ffffffff8302916f R09: 1ffff1100ed51471 R10: dffffc0000000000 R11: ffffed100ed51472 R12: 0000000000000000 R13: ffff8880132ab500 R14: 1ffff9200073df94 R15: ffff888078f34758 FS: 0000555556705380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020001000 CR3: 000000001bfb2000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ovl_dentry_to_fid fs/overlayfs/export.c:240 [inline] ovl_encode_fh+0x2ac/0xc70 fs/overlayfs/export.c:275 exportfs_encode_inode_fh fs/exportfs/expfs.c:407 [inline] exportfs_encode_fh+0x195/0x490 fs/exportfs/expfs.c:438 do_sys_name_to_handle fs/fhandle.c:52 [inline] __do_sys_name_to_handle_at fs/fhandle.c:116 [inline] __se_sys_name_to_handle_at+0x3ad/0x730 fs/fhandle.c:98 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f37d63e4429 Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd5eea5b98 EFLAGS: 00000246 ORIG_RAX: 000000000000012f RAX: ffffffffffffffda RBX: 00007ffd5eea5d68 RCX: 00007f37d63e4429 RDX: 0000000020000300 RSI: 0000000020000240 RDI: 0000000000000003 RBP: 00007f37d6457610 R08: 0000000000001600 R09: 00007ffd5eea5d68 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffd5eea5d58 R14: 0000000000000001 R15: 0000000000000001 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:ovl_encode_real_fh+0x87/0x400 fs/overlayfs/copy_up.c:380 Code: 20 49 c1 ee 03 48 b8 f1 f1 f1 f1 04 f3 f3 f3 49 89 04 1e e8 1b e5 8b fe 48 89 d9 49 8d 9c 24 e0 00 00 00 48 89 d8 48 c1 e8 03 <80> 3c 08 00 74 12 48 89 df e8 0b 61 e6 fe 48 b9 00 00 00 00 00 fc RSP: 0018:ffffc900039efc80 EFLAGS: 00010202 RAX: 000000000000001c RBX: 00000000000000e0 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8880132ab500 RBP: ffffc900039efd30 R08: ffffffff8302916f R09: 1ffff1100ed51471 R10: dffffc0000000000 R11: ffffed100ed51472 R12: 0000000000000000 R13: ffff8880132ab500 R14: 1ffff9200073df94 R15: ffff888078f34758 FS: 0000555556705380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020001000 CR3: 000000001bfb2000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 20 49 c1 and %cl,-0x3f(%rcx) 3: ee out %al,(%dx) 4: 03 48 b8 add -0x48(%rax),%ecx 7: f1 int1 8: f1 int1 9: f1 int1 a: f1 int1 b: 04 f3 add $0xf3,%al d: f3 f3 49 89 04 1e repz xrelease mov %rax,(%r14,%rbx,1) 13: e8 1b e5 8b fe call 0xfe8be533 18: 48 89 d9 mov %rbx,%rcx 1b: 49 8d 9c 24 e0 00 00 lea 0xe0(%r12),%rbx 22: 00 23: 48 89 d8 mov %rbx,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 80 3c 08 00 cmpb $0x0,(%rax,%rcx,1) <-- trapping instruction 2e: 74 12 je 0x42 30: 48 89 df mov %rbx,%rdi 33: e8 0b 61 e6 fe call 0xfee66143 38: 48 rex.W 39: b9 00 00 00 00 mov $0x0,%ecx 3e: 00 fc add %bh,%ah --- 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. If the bug is already fixed, 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 bug's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the bug is a duplicate of another bug, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
