Public bug reported:
Kernel version: 7.0.0-29/30-generic
Function: filemap_get_read_batch in ext4_file_read_iter
Fault address: 0x8000000000000034
Triggered by: tar, apt-get, Plex Transcoder reading large ext4 files
Workaround: IOWeight=10 via systemd cgroup limits prevents triggering
Just FYI
The Linux kernel itself is crashing — not Plex, not Ubuntu, not RAM, not CPU.
Plex is the victim, not the cause.
Here's the chain of events:
Plex (or apt, or tar) reads a large video file or package from the hard drive
The kernel's ext4 filesystem code handles that read request
Deep inside the kernel, in a function called filemap_get_read_batch, there is a
bug in the memory management code
The bug causes the kernel to try to access a memory address that doesn't exist
(0x8000000000000034 — a corrupted pointer)
The CPU detects this illegal memory access and triggers a General Protection
Fault
The entire kernel panics and dies instantly
Because the kernel is dead, everything dies with it — Plex, SSH, the network,
everything
What It's NOT
❌ Not too much RAM — your 30GB is barely touched, Plex only uses 5GB
❌ Not CPU overload — CPU is at near zero during crashes
❌ Not a Plex bug — Plex is just reading files normally
❌ Not a hardware problem — your drives and RAM are healthy
❌ Not a configuration problem we caused
The Real Culprit
It's a bug introduced in Ubuntu kernel 7.0.0 that affects how ext4
filesystems manage memory pages when reading large files quickly. Any
process that reads large files fast can trigger it — we've seen it
triggered by tar, apt-get, and Plex Transcoder so far.
Think of it like a pothole in a road. The road (kernel) has a defect.
Any car (process) that drives over it at speed (full I/O) crashes. We
can't fix the pothole ourselves — only Ubuntu can do that with a kernel
update. What we're doing is slowing all the cars down so they don't hit
the pothole hard enough to crash.
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/2165145
Title:
filemap_get_read_batch in ext4_file_read_iter
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