Troubleshooting Tip: The DHCPD process crashes with a signal 11 segmentation fault, preventing the assignment of a DHCP IP address

[amrit]

Description	This article explains the cause of the DHCPD daemon crash with signal 11, segmentation fault in v7.2, v7.4. and v7.6.
Scope	FortiGate.
Solution	This issue primarily affects lower-end FortiGate models, such as the 40F, 60F/61F; However, it is not limited to these models. If a DHCP server is configured on the FortiGate, the following crash indicates this issue. After the crash, the dhcpd process may stop functioning, and no active dhcpd daemon will be visible in the process list when the following commands are executed. diagnose sys process pidof dhcpd fnsysctl ps diagnose debug crashlog read 343: 2025-07-20 11:54:28 <09587> firmware FortiGate-60F v7.4.7,build2731b2731,250120 (GA.M) (Release) 344: 2025-07-20 11:54:28 <09587> application dhcpd 345: 2025-07-20 11:54:28 <09587> *** signal 11 (Segmentation fault) received *** 346: 2025-07-20 11:54:28 <09587> Register dump: 347: 2025-07-20 11:54:28 <09587> R0: 000000000995eea0 R1: 0000000000000000 R2: 0000000000000000 348: 2025-07-20 11:54:28 <09587> R3: 0000000000000000 R4: 0000000004d3d8a0 R5: 000000000000017f 349: 2025-07-20 11:54:28 <09587> R6: 0000007fd6728440 R7: 0000000000000000 XR: 0000000000000087 350: 2025-07-20 11:54:28 <09587> R9: 000000000080000e R10: 0000000000000000 R11: 0000000000000030 351: 2025-07-20 11:54:28 <09587> R12: 0000007fb3f24e58 R13: 0000000000000000 R14: 0000000000000002 352: 2025-07-20 11:54:28 <09587> R15: 0000000000000160 IP0: 0000000004d45bf8 IP1: 0000007fb3f551c0 353: 2025-07-20 11:54:28 <09587> PR: 0000000000000000 R19: 000000000995eea0 R20: 0000000000000000 354: 2025-07-20 11:54:28 <09587> R21: 00000000ffffffff R22: 000000000995e550 R23: 0000000000000020 355: 2025-07-20 11:54:28 <09587> R24: 0000000000000001 R25: 0000000000000001 R26: 0000000000000000 356: 2025-07-20 11:54:28 <09587> R27: 0000000000000000 R28: 0000000000000000 FP: 0000007fd6728630 357: 2025-07-20 11:54:28 <09587> fault_address: 0000000000000008 sp: 0000007fd6728630 358: 2025-07-20 11:54:28 <09587> pc: 000000000256b360 lr: 000000000256b318 359: 2025-07-20 11:54:28 <09587> pstate: 60000000 (nZCv daif -PAN -UAO) 360: 2025-07-20 11:54:28 <09587> Backtrace: 361: 2025-07-20 11:54:28 <09587> [0x0256b360] => /bin/dhcpd 362: 2025-07-20 11:54:28 <09587> [0x0256ba64] => /bin/dhcpd 363: 2025-07-20 11:54:28 <09587> [0x009855ec] => /bin/dhcpd 364: 2025-07-20 11:54:28 <09587> [0x009742f4] => /bin/dhcpd 365: 2025-07-20 11:54:28 <09587> [0x0044ddfc] => /bin/dhcpd 366: 2025-07-20 11:54:28 <09587> [0x00453794] => /bin/dhcpd 367: 2025-07-20 11:54:28 <09587> [0x00453f98] => /bin/dhcpd 368: 2025-07-20 11:54:28 <09587> [0x004569ec] => /bin/dhcpd 369: 2025-07-20 11:54:28 <09587> [0x004574cc] => /bin/dhcpd 370: 2025-07-20 11:54:28 <09587> [0x7fb3f41f24] => /usr/lib/aarch64-linux-gnu/libc.so.6 371: 2025-07-20 11:54:28 (__libc_start_main+0x000000e4) liboffset 00020f24 372: 2025-07-20 11:54:28 <09587> [0x004498a0] => /bin/dhcpd 373: 2025-07-20 11:54:28 <09587> [0x004498a0] => /bin/dhcpd 374: 2025-07-20 11:54:28 <09587> fortidev 6.0.2.0008 The command 'execute dhcp lease-list' will return an error: Cohmar-FortiGate-60F # execute dhcp lease-list Command fail. Return code -3 The root cause of the problem is conserve mode, which can lead to configuration loss on these devices. This issue has now been resolved in v7.4.9 and v7.6.4. Workaround: To restart the DHCP process, a reboot is required. If an HA A-P cluster is configured, failing over to the secondary node may resolve the issue. Additionally, memory optimization can be applied to prevent conserve mode and DHCP daemon crashes. Related articles: Technical Tip: How to optimize memory consumption for smaller FortiGates  Technical Tip: FortiGate is entering into Conserve Mode during FortiGuard Updates