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.
================================================================================
UBSAN: Undefined behaviour in arch/x86/kernel/uprobes.c:276:56
index 4 is out of range for type 'insn_byte_t [4]'
CPU: 0 PID: 13442 Comm: syz-executor.4 Not tainted 4.19.152-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x22c/0x33e lib/dump_stack.c:118
 ubsan_epilogue+0xe/0x3a lib/ubsan.c:161
 __ubsan_handle_out_of_bounds.cold+0x63/0x6f lib/ubsan.c:383
 is_prefix_bad arch/x86/kernel/uprobes.c:276 [inline]
 uprobe_init_insn arch/x86/kernel/uprobes.c:299 [inline]
 arch_uprobe_analyze_insn+0x9d8/0xaa0 arch/x86/kernel/uprobes.c:868
 prepare_uprobe kernel/events/uprobes.c:611 [inline]
 install_breakpoint kernel/events/uprobes.c:654 [inline]
 uprobe_mmap+0x8c2/0xa70 kernel/events/uprobes.c:1096
 mmap_region+0x552/0x1510 mm/mmap.c:1803
 do_mmap+0x8e8/0x1080 mm/mmap.c:1530
 do_mmap_pgoff include/linux/mm.h:2326 [inline]
 vm_mmap_pgoff+0x197/0x200 mm/util.c:357
 ksys_mmap_pgoff+0x2d1/0x660 mm/mmap.c:1580
 do_syscall_64+0xf9/0x670 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45de59
Code: 0d 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 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fecc1f80c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 0000000000021400 RCX: 000000000045de59
RDX: 0000000000000000 RSI: 0000000000003000 RDI: 0000000020007000
RBP: 000000000118bf78 R08: 0000000000000003 R09: 0000000000000000
R10: 0000000000000412 R11: 0000000000000246 R12: 000000000118bf2c
R13: 00007fff6e7ed42f R14: 00007fecc1f819c0 R15: 000000000118bf2c
================================================================================
EXT4-fs (loop1): bad geometry: block count 512 exceeds size of device (128 blocks)
EXT4-fs (loop1): bad geometry: block count 512 exceeds size of device (128 blocks)
EXT4-fs (loop3): VFS: Can't find ext4 filesystem
nf_conntrack: default automatic helper assignment has been turned off for security reasons and CT-based  firewall rule not found. Use the iptables CT target to attach helpers instead.
EXT4-fs (loop3): VFS: Can't find ext4 filesystem
EXT4-fs (loop1): mounted filesystem without journal. Opts: ,errors=continue
EXT4-fs (loop1): mounted filesystem without journal. Opts: ,errors=continue
EXT4-fs (loop1): mounted filesystem without journal. Opts: ,errors=continue
EXT4-fs (loop1): mounted filesystem without journal. Opts: ,errors=continue
EXT4-fs error (device loop1): ext4_fill_super:4448: inode #2: comm syz-executor.1: iget: root inode unallocated
EXT4-fs (loop1): get root inode failed
EXT4-fs (loop1): mount failed
netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'.
netlink: 'syz-executor.3': attribute type 5 has an invalid length.
EXT4-fs error (device loop1): ext4_fill_super:4448: inode #2: comm syz-executor.1: iget: root inode unallocated
ptrace attach of "/root/syz-executor.5"[13712] was attempted by "/root/syz-executor.5"[13714]
EXT4-fs (loop1): get root inode failed
EXT4-fs (loop1): mount failed
EXT4-fs (loop5): VFS: Can't find ext4 filesystem
EXT4-fs error (device loop1): ext4_fill_super:4448: inode #2: comm syz-executor.1: iget: root inode unallocated
EXT4-fs (loop1): get root inode failed
EXT4-fs (loop1): mount failed
netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'.
EXT4-fs error (device loop1): ext4_fill_super:4448: inode #2: comm syz-executor.1: iget: root inode unallocated
netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'.
EXT4-fs (loop1): get root inode failed
EXT4-fs (loop1): mount failed
ptrace attach of "/root/syz-executor.2"[13781] was attempted by "/root/syz-executor.2"[13784]
EXT4-fs error (device loop1): ext4_fill_super:4448: inode #2: comm syz-executor.1: iget: root inode unallocated
netlink: 60 bytes leftover after parsing attributes in process `syz-executor.2'.
EXT4-fs (loop1): get root inode failed
EXT4-fs (loop1): mount failed
netlink: 60 bytes leftover after parsing attributes in process `syz-executor.2'.
EXT4-fs (loop2): VFS: Can't find ext4 filesystem
EXT4-fs error (device loop1): ext4_fill_super:4448: inode #2: comm syz-executor.1: iget: root inode unallocated
EXT4-fs (loop1): get root inode failed
EXT4-fs (loop1): mount failed
netlink: 60 bytes leftover after parsing attributes in process `syz-executor.5'.
EXT4-fs error (device loop1): ext4_fill_super:4448: inode #2: comm syz-executor.1: iget: root inode unallocated
EXT4-fs (loop1): get root inode failed
EXT4-fs (loop1): mount failed
netlink: 60 bytes leftover after parsing attributes in process `syz-executor.5'.
EXT4-fs (loop5): VFS: Can't find ext4 filesystem
EXT4-fs error (device loop1): ext4_fill_super:4448: inode #2: comm syz-executor.1: iget: root inode unallocated
EXT4-fs (loop1): get root inode failed
EXT4-fs (loop1): mount failed
EXT4-fs error (device loop1): ext4_fill_super:4448: inode #2: comm syz-executor.1: iget: root inode unallocated
EXT4-fs (loop1): get root inode failed
EXT4-fs (loop1): mount failed
EXT4-fs (loop0): VFS: Can't find ext4 filesystem
EXT4-fs error (device loop1): ext4_fill_super:4448: inode #2: comm syz-executor.1: iget: root inode unallocated
EXT4-fs (loop1): get root inode failed
EXT4-fs (loop1): mount failed
EXT4-fs (loop2): VFS: Can't find ext4 filesystem
EXT4-fs (loop2): VFS: Can't find ext4 filesystem
EXT4-fs error (device loop1): ext4_fill_super:4448: inode #2: comm syz-executor.1: iget: root inode unallocated
EXT4-fs (loop1): get root inode failed
EXT4-fs (loop1): mount failed
EXT4-fs error (device loop1): ext4_fill_super:4448: inode #2: comm syz-executor.1: iget: root inode unallocated
EXT4-fs (loop1): get root inode failed
EXT4-fs (loop1): mount failed
EXT4-fs error (device loop1): ext4_fill_super:4448: inode #2: comm syz-executor.1: iget: root inode unallocated
EXT4-fs (loop1): get root inode failed
EXT4-fs (loop1): mount failed
Unknown ioctl 1074835115
EXT4-fs error (device loop1): ext4_fill_super:4448: inode #2: comm syz-executor.1: iget: root inode unallocated
EXT4-fs (loop1): get root inode failed
EXT4-fs (loop1): mount failed
netlink: 72 bytes leftover after parsing attributes in process `syz-executor.2'.
netlink: 72 bytes leftover after parsing attributes in process `syz-executor.2'.
EXT4-fs error (device loop1): ext4_fill_super:4448: inode #2: comm syz-executor.1: iget: root inode unallocated
EXT4-fs (loop1): get root inode failed
EXT4-fs (loop1): mount failed
Unknown ioctl 4728
EXT4-fs error (device loop1): ext4_fill_super:4448: inode #2: comm syz-executor.1: iget: root inode unallocated
EXT4-fs (loop1): get root inode failed
EXT4-fs (loop1): mount failed