Warning from free_reserved_area() in next-20260325+

Bert Karwatzki
2026-03-27T14:02:16Z

Starting with linux next-20260325 I see the following warning early in the
boot process of a machine running debian stable (trixie) (except for the kernel):

[ 0.027118] [ T0] ------------[ cut here ]------------
[ 0.027118] [ T0] Cannot free reserved memory because of deferred initialization of the memory map
[ 0.027119] [ T0] WARNING: mm/memblock.c:904 at __free_reserved_area+0xa9/0xc0, CPU#0: swapper/0/0
[ 0.027122] [ T0] Modules linked in:
[ 0.027123] [ T0] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 7.0.0-rc5-next-20260326-master #385 PREEMPT_RT
[ 0.027125] [ T0] Hardware name: ASUS System Product Name/ROG STRIX B850-F GAMING WIFI, BIOS 1627 02/05/2026
[ 0.027125] [ T0] RIP: 0010:__free_reserved_area+0xa9/0xc0
[ 0.027126] [ T0] Code: 48 89 df 48 89 ee e8 06 fe ff ff 48 89 c3 48 39 e8 72 a0 5b 4c 89 e8 5d 41 5c 41 5d 41 5e c3 cc cc cc cc 48 8d 3d 97 c2 c6 00 <67> 48 0f b9 3a 45 31 ed eb df 66 66 2e 0f 1f 84 00 00 00 00 00 66
[ 0.027127] [ T0] RSP: 0000:ffffffff9b203e98 EFLAGS: 00010202
[ 0.027128] [ T0] RAX: 0000000e91c00001 RBX: ffffffff9b100c0f RCX: 0000000080000001
[ 0.027128] [ T0] RDX: 00000000000000cc RSI: 0000000e2d42d000 RDI: ffffffff9b32ef60
[ 0.027128] [ T0] RBP: ffff9eeafdd6fbc0 R08: 0000000000000000 R09: 0000000000000001
[ 0.027129] [ T0] R10: 0000000000001000 R11: 8000000000000163 R12: 000000000000006f
[ 0.027129] [ T0] R13: 0000000000000000 R14: 0000000000000045 R15: 000000005c8a1000
[ 0.027129] [ T0] FS: 0000000000000000(0000) GS:ffff9eeb21c05000(0000) knlGS:0000000000000000
[ 0.027130] [ T0] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 0.027130] [ T0] CR2: ffff9ee8ad801000 CR3: 0000000e2ce1e000 CR4: 0000000000f50ef0
[ 0.027131] [ T0] PKRU: 55555554
[ 0.027131] [ T0] Call Trace:
[ 0.027132] [ T0] <TASK>
[ 0.027132] [ T0] free_reserved_area+0x89/0xd0
[ 0.027133] [ T0] alternative_instructions+0xee/0x110
[ 0.027136] [ T0] arch_cpu_finalize_init+0x10f/0x160
[ 0.027138] [ T0] start_kernel+0x686/0x710
[ 0.027140] [ T0] x86_64_start_reservations+0x24/0x30
[ 0.027141] [ T0] x86_64_start_kernel+0xd4/0xe0
[ 0.027142] [ T0] common_startup_64+0x13e/0x141
[ 0.027143] [ T0] </TASK>
[ 0.027144] [ T0] ---[ end trace 0000000000000000 ]---

The Hardware used is this:

$ cat /proc/cpuinfo
processor : 0
vendor_id : AuthenticAMD
cpu family : 26
model : 68
model name : AMD Ryzen 9 9950X 16-Core Processor
stepping : 0
microcode : 0xb404035
cpu MHz : 3607.683
cache size : 1024 KB
physical id : 0
siblings : 32
core id : 0
cpu cores : 16
apicid : 0
initial apicid : 0
fpu : yes
fpu_exception : yes
cpuid level : 16
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm constant_tsc rep_good amd_lbr_v2 nopl xtopology nonstop_tsc cpuid extd_apicid aperfmperf rapl pni pclmulqdq monitor ssse3 fma cx16 sse4_1 sse4_2 movbe popcnt aes xsave avx f16c rdrand lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt tce topoext perfctr_core perfctr_nb bpext perfctr_llc mwaitx cpuid_fault cpb cat_l3 cdp_l3 hw_pstate ssbd mba perfmon_v2 ibrs ibpb stibp ibrs_enhanced vmmcall fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid cqm rdt_a avx512f avx512dq rdseed adx smap avx512ifma clflushopt clwb avx512cd sha_ni avx512bw avx512vl xsaveopt xsavec xgetbv1 xsaves cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm_local user_shstk avx_vnni avx512_bf16 clzero irperf xsaveerptr rdpru wbnoinvd cppc arat npt lbrv svm_lock nrip_save tsc_scale vmcb_clean flushbyasid decodeassists pausefilter pfthreshold avic v_vmsave_vmload vgif x2avic v_spec_ctrl vnmi avx512vbmi umip pku ospke avx512_vbmi2 gfni vaes vpclmulqdq avx512_vnni avx512_bitalg avx512_vpopcntdq rdpid bus_lock_detect movdiri movdir64b overflow_recov succor smca fsrm avx512_vp2intersect flush_l1d amd_lbr_pmc_freeze
bugs : sysret_ss_attrs spectre_v1 spectre_v2 spec_store_bypass srso spectre_v2_user vmscape
bogomips : 8599.98
TLB size : 192 4K pages
clflush size : 64
cache_alignment : 64
address sizes : 48 bits physical, 48 bits virtual
power management: ts ttp tm hwpstate cpb eff_freq_ro [13] [14]

$ lspci
00:00.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge Root Complex
00:00.2 IOMMU: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge IOMMU
00:01.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge Dummy Host Bridge
00:01.1 PCI bridge: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge GPP Bridge
00:01.2 PCI bridge: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge GPP Bridge
00:02.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge Dummy Host Bridge
00:02.1 PCI bridge: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge GPP Bridge
00:03.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge Dummy Host Bridge
00:04.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge Dummy Host Bridge
00:08.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge Dummy Host Bridge
00:08.1 PCI bridge: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge Internal GPP Bridge to Bus [C:A]
00:08.3 PCI bridge: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge Internal GPP Bridge to Bus [C:A]
00:14.0 SMBus: Advanced Micro Devices, Inc. [AMD] FCH SMBus Controller (rev 71)
00:14.3 ISA bridge: Advanced Micro Devices, Inc. [AMD] FCH LPC Bridge (rev 51)
00:18.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge Data Fabric; Function 0
00:18.1 Host bridge: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge Data Fabric; Function 1
00:18.2 Host bridge: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge Data Fabric; Function 2
00:18.3 Host bridge: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge Data Fabric; Function 3
00:18.4 Host bridge: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge Data Fabric; Function 4
00:18.5 Host bridge: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge Data Fabric; Function 5
00:18.6 Host bridge: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge Data Fabric; Function 6
00:18.7 Host bridge: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge Data Fabric; Function 7
01:00.0 PCI bridge: Advanced Micro Devices, Inc. [AMD/ATI] Navi 10 XL Upstream Port of PCI Express Switch (rev 25)
02:00.0 PCI bridge: Advanced Micro Devices, Inc. [AMD/ATI] Navi 10 XL Downstream Port of PCI Express Switch (rev 25)
03:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Navi 44 [RX 9060 XT] (rev c0)
03:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Navi 48 HDMI/DP Audio Controller
04:00.0 Non-Volatile memory controller: Samsung Electronics Co Ltd NVMe SSD 9100 PRO [PM9E1]
05:00.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] 600 Series Chipset PCIe Switch Upstream Port (rev 01)
06:00.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] 600 Series Chipset PCIe Switch Downstream Port (rev 01)
06:06.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] 600 Series Chipset PCIe Switch Downstream Port (rev 01)
06:07.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] 600 Series Chipset PCIe Switch Downstream Port (rev 01)
06:08.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] 600 Series Chipset PCIe Switch Downstream Port (rev 01)
06:0c.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] 600 Series Chipset PCIe Switch Downstream Port (rev 01)
06:0d.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] 600 Series Chipset PCIe Switch Downstream Port (rev 01)
08:00.0 Ethernet controller: Intel Corporation Ethernet Controller I226-V (rev 06)
09:00.0 Network controller: MEDIATEK Corp. Device 7925
0b:00.0 USB controller: Advanced Micro Devices, Inc. [AMD] 800 Series Chipset USB 3.x XHCI Controller (rev 01)
0c:00.0 SATA controller: Advanced Micro Devices, Inc. [AMD] 600 Series Chipset SATA Controller (rev 01)
0d:00.0 Non-Essential Instrumentation [1300]: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge PCIe Dummy Function (rev c1)
0d:00.2 Encryption controller: Advanced Micro Devices, Inc. [AMD] Family 19h PSP/CCP
0d:00.3 USB controller: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge USB 3.1 xHCI
0d:00.4 USB controller: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge USB 3.1 xHCI
0e:00.0 USB controller: Advanced Micro Devices, Inc. [AMD] Raphael/Granite Ridge USB 2.0 xHCI

Memory used is 64G:
$ LANG=C free
total used free shared buff/cache available
Mem: 65500068 3584080 56709424 70916 5912256 61915988
Swap: 78125052 0 78125052

Bert Karwatzki