L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html for details.
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 7878 Comm: syz-executor.2 Not tainted 4.19.143-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__sock_release+0xbb/0x2a0 net/socket.c:579
Code: ff df 48 c1 ea 03 80 3c 02 00 0f 85 c9 01 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 63 28 49 8d 7c 24 10 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 b2 01 00 00 48 89 df 41 ff 54 24 10 48 8d 7b 20
RSP: 0018:ffff888045a77df8 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff88807fecb5c0 RCX: 0000000000001879
RDX: 0000000000000002 RSI: 000000007fddc9ed RDI: 0000000000000010
RBP: ffff88807fecb6c8 R08: ffffffff8b3f6c48 R09: 0000000000000000
R10: ffff888045a68f08 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88807fecb5e8 R14: 0000000000000000 R15: ffff8880a943ee20
FS:  00007fe0f21af700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff51ff0b700 CR3: 00000000a8317000 CR4: 00000000001426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 sock_close+0x15/0x20 net/socket.c:1140
 __fput+0x2ce/0x890 fs/file_table.c:278
 task_work_run+0x148/0x1c0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:193 [inline]
 exit_to_usermode_loop+0x251/0x2a0 arch/x86/entry/common.c:167
 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
 do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45d5b9
Code: 5d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fe0f21aec78 EFLAGS: 00000246 ORIG_RAX: 00000000000000e9
RAX: 0000000000000000 RBX: 0000000000002ac0 RCX: 000000000045d5b9
RDX: 0000000000000006 RSI: 0000000000000001 RDI: 0000000000000007
RBP: 000000000118cf88 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000200001c0 R11: 0000000000000246 R12: 000000000118cf4c
R13: 00007ffdcdab1caf R14: 00007fe0f21af9c0 R15: 000000000118cf4c
Modules linked in:
---[ end trace aafda6ecd7d33e27 ]---
RIP: 0010:__sock_release+0xbb/0x2a0 net/socket.c:579
Code: ff df 48 c1 ea 03 80 3c 02 00 0f 85 c9 01 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 63 28 49 8d 7c 24 10 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 b2 01 00 00 48 89 df 41 ff 54 24 10 48 8d 7b 20
RSP: 0018:ffff888045a77df8 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff88807fecb5c0 RCX: 0000000000001879
RDX: 0000000000000002 RSI: 000000007fddc9ed RDI: 0000000000000010
RBP: ffff88807fecb6c8 R08: ffffffff8b3f6c48 R09: 0000000000000000
R10: ffff888045a68f08 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88807fecb5e8 R14: 0000000000000000 R15: ffff8880a943ee20
FS:  00007fe0f21af700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fecad4a7db8 CR3: 00000000a8317000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400