9p: Unknown Cache mode or invalid value mmap000000000000000000000000xffffffffffffffff 9pnet: Tag 65535 still in use ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 0 PID: 14855 at lib/refcount.c:28 refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28 Modules linked in: CPU: 0 UID: 0 PID: 14855 Comm: syz.2.2082 Not tainted 6.17.0-rc1-syzkaller #0 PREEMPT(full) 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 b8 9a da fc 84 db 0f 85 66 ff ff ff e8 cb 9f da fc c6 05 d7 59 b3 0b 01 90 48 c7 c7 20 97 15 8c e8 27 91 99 fc 90 <0f> 0b 90 90 e9 43 ff ff ff e8 a8 9f da fc 0f b6 1d b2 59 b3 0b 31 RSP: 0018:ffffc9000e1ef960 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc9000c001000 RDX: 0000000000080000 RSI: ffffffff817a02d5 RDI: 0000000000000001 RBP: ffff88804be92008 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffff88804be92008 R13: ffff8880250e3400 R14: dffffc0000000000 R15: 1ffff92001c3df37 FS: 0000000000000000(0000) GS:ffff8880974c6000(0063) knlGS:00000000f54ceb40 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 00000000f5505528 CR3: 000000002802d000 CR4: 0000000000352ef0 Call Trace: __refcount_sub_and_test include/linux/refcount.h:400 [inline] __refcount_dec_and_test include/linux/refcount.h:432 [inline] refcount_dec_and_test include/linux/refcount.h:450 [inline] p9_req_put+0x1ec/0x250 net/9p/client.c:404 p9_tag_cleanup net/9p/client.c:431 [inline] p9_client_destroy+0x22b/0x480 net/9p/client.c:1086 v9fs_session_init+0xbab/0x1a80 fs/9p/v9fs.c:490 v9fs_mount+0xc5/0xa90 fs/9p/vfs_super.c:122 legacy_get_tree+0x10c/0x220 fs/fs_context.c:666 vfs_get_tree+0x8b/0x340 fs/super.c:1815 do_new_mount fs/namespace.c:3805 [inline] path_mount+0x1482/0x1fd0 fs/namespace.c:4120 do_mount fs/namespace.c:4133 [inline] __do_sys_mount fs/namespace.c:4344 [inline] __se_sys_mount fs/namespace.c:4321 [inline] __ia32_sys_mount+0x28b/0x310 fs/namespace.c:4321 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x7c/0x3a0 arch/x86/entry/syscall_32.c:306 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf70de579 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:00000000f54ce55c EFLAGS: 00000296 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 00000000800001c0 RCX: 0000000080000080 RDX: 0000000080000040 RSI: 0000000000008017 RDI: 0000000080000100 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- 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