------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 0 PID: 3990 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 lib/refcount.c:25 Modules linked in: CPU: 0 PID: 3990 Comm: syz-executor.2 Not tainted 5.15.0-rc6-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 97 b4 9b fd 84 db 0f 85 36 ff ff ff e8 da ac 9b fd 48 c7 c7 c0 65 e3 89 c6 05 1f 57 7f 09 01 e8 2d 45 19 05 <0f> 0b e9 17 ff ff ff e8 bb ac 9b fd 0f b6 1d 04 57 7f 09 31 ff 89 RSP: 0018:ffffc90003247f10 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000040000 RSI: ffffffff815dcf48 RDI: fffff52000648fd4 RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff815d6cbe R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f0e8c05f700(0000) GS:ffff88802cc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1b59c80de8 CR3: 00000000794a3000 CR4: 0000000000150ee0 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] __do_sys_memfd_secret mm/secretmem.c:221 [inline] __se_sys_memfd_secret mm/secretmem.c:194 [inline] __x64_sys_memfd_secret+0x182/0x1e0 mm/secretmem.c:194 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f0e8eae9a39 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f0e8c05f188 EFLAGS: 00000246 ORIG_RAX: 00000000000001bf RAX: ffffffffffffffda RBX: 00007f0e8ebecf60 RCX: 00007f0e8eae9a39 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f0e8eb43e8f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd4b5a638f R14: 00007f0e8c05f300 R15: 0000000000022000