Hello, syzbot found the following issue on: HEAD commit: ba643b6d8440 Merge tag 'irq_urgent_for_v6.14_rc3' of git:/.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=12ac6898580000 kernel config: https://syzkaller.appspot.com/x/.config?x=40c8b8384bc47ab0 dashboard link: https://syzkaller.appspot.com/bug?extid=81d70446f786c253e1b1 compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 userspace arch: i386 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-ba643b6d.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/7f81490db045/vmlinux-ba643b6d.xz kernel image: https://storage.googleapis.com/syzbot-assets/5ca8bab9c8a7/bzImage-ba643b6d.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+81d70446f786c253e1b1@xxxxxxxxxxxxxxxxxxxxxxxxx ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 0 PID: 21153 at lib/refcount.c:28 refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28 Modules linked in: CPU: 0 UID: 0 PID: 21153 Comm: syz.3.12815 Not tainted 6.14.0-rc2-syzkaller-00346-gba643b6d8440 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28 Code: ff 89 de e8 08 71 f7 fc 84 db 0f 85 66 ff ff ff e8 5b 76 f7 fc c6 05 ef 92 88 0b 01 90 48 c7 c7 80 f0 d2 8b e8 37 b0 b7 fc 90 <0f> 0b 90 90 e9 43 ff ff ff e8 38 76 f7 fc 0f b6 1d ca 92 88 0b 31 RSP: 0018:ffffc90004e97ac8 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc90031b18000 RDX: 0000000000080000 RSI: ffffffff817a1236 RDI: 0000000000000001 RBP: ffff88806a5878fc R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000002 R12: ffff88806a5878fc R13: ffff88806a587808 R14: 0000000000000000 R15: ffff88802b1292c0 FS: 0000000000000000(0000) GS:ffff88802b400000(0063) knlGS:00000000f5064b40 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 0000000031cf2ffc CR3: 000000005e816000 CR4: 0000000000352ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 00000000000f0102 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: <TASK> __refcount_sub_and_test include/linux/refcount.h:275 [inline] __refcount_dec_and_test include/linux/refcount.h:307 [inline] refcount_dec_and_test include/linux/refcount.h:325 [inline] kref_put include/linux/kref.h:64 [inline] sco_conn_put+0x2ea/0x4c0 net/bluetooth/sco.c:107 sco_chan_del+0x9c/0x1b0 net/bluetooth/sco.c:236 __sco_sock_close+0xab/0x210 net/bluetooth/sco.c:511 sco_sock_close net/bluetooth/sco.c:526 [inline] sco_sock_release+0x6f/0x2d0 net/bluetooth/sco.c:1300 __sock_release+0xb0/0x270 net/socket.c:647 sock_close+0x1c/0x30 net/socket.c:1398 __fput+0x3ff/0xb70 fs/file_table.c:464 task_work_run+0x14e/0x250 kernel/task_work.c:227 get_signal+0x1d3/0x26c0 kernel/signal.c:2809 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218 __do_fast_syscall_32+0x80/0x120 arch/x86/entry/common.c:389 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf7f83579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f506455c EFLAGS: 00000296 ORIG_RAX: 000000000000016a RAX: fffffffffffffffc RBX: 000000000000000a RCX: 0000000080000040 RDX: 0000000000000008 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 </TASK> ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi --- 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 report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title 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
