Kernel: Executables sometimes disappear after a process crashes

[Lubrsi]

For example, I was debugging a UAF in the bytecode optimizer and this happened:

380.899 WebContent(47:47): length: unknown type: -303174163 (0x-12121213)
380.899 WebContent(47:47): ASSERTION FAILED: false
../../Userland/Libraries/LibJS/Bytecode/Op.h:968
380.899 [#0 WebContent(47:47)]: Terminating WebContent(47) due to signal 6
380.907 [#0 FinalizerTask(4:4)]: Backtrace:
0x00000000deadc0de  Kernel::Processor::switch_context(Kernel::Thread*&, Kernel::Thread*&) + 0x383
380.907 [#0 FinalizerTask(4:4)]: Generating coredump for pid: 47
381.036 CrashDaemon(9:9): New coredump file: /tmp/coredump/WebContent_47_1650928417
381.046 SystemServer(6:6): WebContent: binary "/bin/WebContent" does not exist, skipping service.
381.049 SystemServer(6:6): WebContent: binary "/bin/WebContent" does not exist, skipping service.
381.049 SystemServer(6:6): WebContent: binary "/bin/WebContent" does not exist, skipping service.
381.057 SystemServer(6:6): WebContent: binary "/bin/WebContent" does not exist, skipping service.
381.057 SystemServer(6:6): WebContent: binary "/bin/WebContent" does not exist, skipping service

When re-running with Meta/serenity.sh run x86_64, the disk image appears corrupted:

checking existing image
e2fsck 1.45.5 (07-Jan-2020)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Entry 'WebContent' in /bin (25153) has deleted/unused inode 25254.  Clear? yes

Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
Block bitmap differences:  -(34272--34303) -164613 -(197683--197806) -(231122--231185) -(394096--394111) -(427136--427263) -(501575--501590)
Fix? yes

Free blocks count wrong for group #1 (22122, counted=22154).
Fix? yes

Free blocks count wrong for group #5 (20265, counted=20266).
Fix? yes

Free blocks count wrong for group #6 (22071, counted=22195).
Fix? yes

Free blocks count wrong for group #7 (18062, counted=18126).
Fix? yes

Free blocks count wrong for group #12 (18625, counted=18641).
Fix? yes

Free blocks count wrong for group #13 (23073, counted=23201).
Fix? yes

Free blocks count wrong for group #15 (2868, counted=2884).
Fix? yes

Free blocks count wrong (315892, counted=316273).
Fix? yes


_disk_image: ***** FILESYSTEM WAS MODIFIED *****
_disk_image: 11498/67072 files (6.2% non-contiguous), 189804/506077 blocks
done