CVE-2023-54278 s390/vmem: split pages when debug pagealloc is enabled
A kernel panic occurs during boot on s390 systems if debug pagealloc is enabled, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Not stated
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-54278?
CVE-2023-54278 is a denial of service vulnerability in Linux, published on 30 Dec 2025.
Official description
In the Linux kernel, the following vulnerability has been resolved:
s390/vmem: split pages when debug pagealloc is enabled
Since commit bb1520d581a3 ("s390/mm: start kernel with DAT enabled") the kernel crashes early during boot when debug pagealloc is enabled:
mem auto-init: stack:off, heap alloc:off, heap free:off addressing exception: 0005 ilc:2 [#1] SMP DEBUG_PAGEALLOC Modules linked in: CPU: 0 PID: 0 Comm: swapper Not tainted 6.5.0-rc3-09759-gc5666c912155 #630 [..] Krnl Code: 00000000001325f6: ec5600248064 cgrj %r5,%r6,8,000000000013263e 00000000001325fc: eb880002000c srlg %r8,%r8,2 #0000000000132602: b2210051 ipte %r5,%r1,%r0,0 >0000000000132606: b90400d1 lgr %r13,%r1 000000000013260a: 41605008 la %r6,8(%r5) 000000000013260e: a7db1000 aghi %r13,4096 0000000000132612: b221006d ipte %r6,%r13,%r0,0 0000000000132616: e3d0d0000171 lay %r13,4096(%r13)
Call Trace: __kernel_map_pages+0x14e/0x320 __free_pages_ok+0x23a/0x5a8) free_low_memory_core_early+0x214/0x2c8 memblock_free_all+0x28/0x58 mem_init+0xb6/0x228 mm_core_init+0xb6/0x3b0 start_kernel+0x1d2/0x5a8 startup_continue+0x36/0x40 Kernel panic - not syncing: Fatal exception: panic_on_oops
This is caused by using large mappings on machines with EDAT1/EDAT2. Add the code to split the mappings into 4k pages if debug pagealloc is enabled by CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT or the debug_pagealloc kernel command line option.
Which versions are affected by CVE-2023-54278?
How do I fix CVE-2023-54278?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2023-54278 being exploited?
There is no known exploitation of CVE-2023-54278 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2023-54278, DEBIAN-CVE-2023-54278, GHSA-wr38-v9r2-5hhw, UBUNTU-CVE-2023-54278.