Hello, syzbot found the following issue on: HEAD commit: dfd4b508c8c6 Merge tag 'drm-fixes-2025-08-16' of https://g.. git tree: upstream console+strace: https://syzkaller.appspot.com/x/log.txt?x=13c6f3a2580000 kernel config: https://syzkaller.appspot.com/x/.config?x=98e114f4eb77e551 dashboard link: https://syzkaller.appspot.com/bug?extid=6a141f31cc9495a3dcc1 compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=135edaf0580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=100ad3a2580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/289d8459a101/disk-dfd4b508.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/653f0f06a0ea/vmlinux-dfd4b508.xz kernel image: https://storage.googleapis.com/syzbot-assets/7ab9bdbe6030/bzImage-dfd4b508.xz mounted in repro: https://storage.googleapis.com/syzbot-assets/69f46f8377ed/mount_0.gz The issue was bisected to: commit d2d6422f8bd17c6bb205133e290625a564194496 Author: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> Date: Fri Sep 6 10:59:04 2024 +0000 x86: Allow to enable PREEMPT_RT. bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=119b63a2580000 final oops: https://syzkaller.appspot.com/x/report.txt?x=139b63a2580000 console output: https://syzkaller.appspot.com/x/log.txt?x=159b63a2580000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+6a141f31cc9495a3dcc1@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: d2d6422f8bd1 ("x86: Allow to enable PREEMPT_RT.") WARNING: The mand mount option has been deprecated and and is ignored by this kernel. Remove the mand option from the mount to silence this warning. ======================================================= ------------[ cut here ]------------ rtmutex deadlock detected WARNING: CPU: 1 PID: 5838 at kernel/locking/rtmutex.c:1674 rt_mutex_handle_deadlock+0x28/0xb0 kernel/locking/rtmutex.c:1674 Modules linked in: CPU: 1 UID: 0 PID: 5838 Comm: syz-executor124 Tainted: G W 6.17.0-rc1-syzkaller-00199-gdfd4b508c8c6 #0 PREEMPT_{RT,(full)} Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:rt_mutex_handle_deadlock+0x28/0xb0 kernel/locking/rtmutex.c:1674 Code: 90 90 41 57 41 56 41 55 41 54 53 83 ff dd 0f 85 8c 00 00 00 48 89 f7 e8 c6 2c 01 00 90 48 c7 c7 00 09 0b 8b e8 79 d8 8a f6 90 <0f> 0b 90 90 4c 8d 3d 00 00 00 00 65 48 8b 1c 25 08 b0 f5 91 4c 8d RSP: 0018:ffffc90004b0ec90 EFLAGS: 00010246 RAX: 8abe693e197be100 RBX: ffffc90004b0ed20 RCX: ffff88803d511dc0 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90004b0ee28 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: ffffed1017124863 R12: 1ffff92000961da0 R13: ffffffff8af85119 R14: ffff88803d528048 R15: dffffc0000000000 FS: 000055555dc68380(0000) GS:ffff8881269c5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000002fe82000 CR4: 00000000003526f0 Call Trace: <TASK> __rt_mutex_slowlock kernel/locking/rtmutex.c:1734 [inline] __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline] rt_mutex_slowlock+0x692/0x6e0 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] __mutex_lock_common kernel/locking/rtmutex_api.c:536 [inline] mutex_lock_nested+0x16a/0x1d0 kernel/locking/rtmutex_api.c:547 hfs_find_init+0x184/0x200 fs/hfs/bfind.c:-1 hfs_ext_read_extent fs/hfs/extent.c:200 [inline] hfs_extend_file+0x2ee/0x1230 fs/hfs/extent.c:401 hfs_bmap_reserve+0x107/0x430 fs/hfs/btree.c:269 __hfs_ext_write_extent+0x1fa/0x470 fs/hfs/extent.c:121 __hfs_ext_cache_extent+0x6b/0x9b0 fs/hfs/extent.c:174 hfs_ext_read_extent fs/hfs/extent.c:202 [inline] hfs_extend_file+0x316/0x1230 fs/hfs/extent.c:401 hfs_get_block+0x3d7/0xbd0 fs/hfs/extent.c:353 __block_write_begin_int+0x6b5/0x1900 fs/buffer.c:2145 block_write_begin fs/buffer.c:2256 [inline] cont_write_begin+0x789/0xb50 fs/buffer.c:2594 hfs_write_begin+0x66/0xb0 fs/hfs/inode.c:52 cont_expand_zero fs/buffer.c:2522 [inline] cont_write_begin+0x2fd/0xb50 fs/buffer.c:2584 hfs_write_begin+0x66/0xb0 fs/hfs/inode.c:52 hfs_file_truncate+0x190/0x9c0 fs/hfs/extent.c:494 hfs_inode_setattr+0x4a9/0x670 fs/hfs/inode.c:654 notify_change+0xb31/0xe60 fs/attr.c:552 do_truncate+0x1a4/0x220 fs/open.c:68 vfs_truncate+0x493/0x520 fs/open.c:118 do_sys_truncate+0xdb/0x190 fs/open.c:141 __do_sys_truncate fs/open.c:153 [inline] __se_sys_truncate fs/open.c:151 [inline] __x64_sys_truncate+0x5b/0x70 fs/open.c:151 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa1dc925b99 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 17 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff5e8c2808 EFLAGS: 00000246 ORIG_RAX: 000000000000004c RAX: ffffffffffffffda RBX: 0031656c69662f2e RCX: 00007fa1dc925b99 RDX: 00007fa1dc925b99 RSI: 0000000001001bfc RDI: 0000200000000040 RBP: 00007fa1dc9995f0 R08: 000055555dc694c0 R09: 000055555dc694c0 R10: 000055555dc694c0 R11: 0000000000000246 R12: 00007fff5e8c2830 R13: 00007fff5e8c2a58 R14: 431bde82d7b634db R15: 00007fa1dc96e03b </TASK> --- 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
