------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 1 PID: 15105 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 lib/refcount.c:25 Modules linked in: CPU: 1 PID: 15105 Comm: syz-executor.2 Not tainted 5.16.0-rc3-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 RIP: 0010:refcount_warn_saturate+0x169/0x1e0 lib/refcount.c:25 Code: 09 31 ff 89 de e8 57 e7 9c fd 84 db 0f 85 36 ff ff ff e8 6a e3 9c fd 48 c7 c7 60 d4 04 8a c6 05 9a ef a1 09 01 e8 31 c9 25 05 <0f> 0b e9 17 ff ff ff e8 4b e3 9c fd 0f b6 1d 7f ef a1 09 31 ff 89 RSP: 0018:ffffc90024877b80 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000040000 RSI: ffffffff815f0d88 RDI: fffff5200490ef62 RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000001 R10: ffffffff815eab2e R11: 0000000000000000 R12: ffff88807647a780 R13: ffff88807647a78c R14: 1ffff9200490ef75 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88802cb00000(0063) knlGS:00000000f44e1b40 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 00000000ffa64ec4 CR3: 0000000049297000 CR4: 0000000000152ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __refcount_add include/linux/refcount.h:199 [inline] __refcount_inc include/linux/refcount.h:250 [inline] refcount_inc include/linux/refcount.h:267 [inline] v9fs_fid_find+0x471/0x4e0 fs/9p/fid.c:111 v9fs_fid_lookup_with_uid+0xa2/0xae0 fs/9p/fid.c:160 v9fs_vfs_getattr_dotl+0xd3/0x2c0 fs/9p/vfs_inode_dotl.c:479 vfs_getattr_nosec+0x2b4/0x370 fs/stat.c:123 vfs_getattr fs/stat.c:160 [inline] vfs_statx+0x18d/0x390 fs/stat.c:225 vfs_fstatat fs/stat.c:243 [inline] vfs_stat include/linux/fs.h:3353 [inline] __do_compat_sys_newstat+0x91/0x110 fs/stat.c:682 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c RIP: 0023:0xf6ee7549 Code: 03 74 c0 01 10 05 03 74 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 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:00000000f44e15fc EFLAGS: 00000296 ORIG_RAX: 000000000000006a RAX: ffffffffffffffda RBX: 0000000020000f00 RCX: 0000000020000f40 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess): 0: 03 74 c0 01 add 0x1(%rax,%rax,8),%esi 4: 10 05 03 74 b8 01 adc %al,0x1b87403(%rip) # 0x1b8740d a: 10 06 adc %al,(%rsi) c: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 10: 10 07 adc %al,(%rdi) 12: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi 16: 10 08 adc %cl,(%rax) 18: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1c: 00 00 add %al,(%rax) 1e: 00 00 add %al,(%rax) 20: 00 51 52 add %dl,0x52(%rcx) 23: 55 push %rbp 24: 89 e5 mov %esp,%ebp 26: 0f 34 sysenter 28: cd 80 int $0x80 * 2a: 5d pop %rbp <-- trapping instruction 2b: 5a pop %rdx 2c: 59 pop %rcx 2d: c3 retq 2e: 90 nop 2f: 90 nop 30: 90 nop 31: 90 nop 32: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 39: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi