Random Zephyr hangs due to RNG / Entropy

RE: Random Zephyr hangs due to RNG / Entropy

JONATHAN LL — Wed, 14 Jan 2026 09:10:20 GMT

Thanks for confirming.

RE: Random Zephyr hangs due to RNG / Entropy

Veijo Boman — Wed, 14 Jan 2026 05:48:40 GMT

Apparently bug is still valid as my problem got fixed by workaround presented above.

RE: Random Zephyr hangs due to RNG / Entropy

JONATHAN LL — Thu, 08 Jan 2026 13:46:54 GMT

Hi, Can you create a new ticket for this and link to this ticket in the new case?

Regards,
Jonathan

RE: Random Zephyr hangs due to RNG / Entropy

Veijo Boman — Thu, 08 Jan 2026 12:30:38 GMT

I wonder if this bug is still valid? I'm running nRF52840 devkit with Zephry 2.9.1 application which sends BLE mesh messages as much as possible. Usually within an hour it crashes:

00> [01:06:12.418,426] <err> os: ***** MPU FAULT *****
00> [01:06:12.418,426] <err> os: Stacking error (context area might be not valid)
00> [01:06:12.418,426] <err> os: r0/a1: 0x00000000 r1/a2: 0x00000000 r2/a3: 0x00000000
00> [01:06:12.418,457] <err> os: r3/a4: 0x00000000 r12/ip: 0x2000eda8 r14/lr: 0x2000ed80
00> [01:06:12.418,457] <err> os: xpsr: 0x41000200
00> [01:06:12.418,487] <err> os: Faulting instruction address (r15/pc): 0x0004bb66
00> [01:06:12.418,518] <err> os: >>> ZEPHYR FATAL ERROR 2: Stack overflow on CPU 0
00> [01:06:12.418,548] <err> os: Current thread: 0x200043b8 (unknown)
00> [01:06:12.686,706] <err> os: Halting system

Checked address 0x0004bb66 from map-file:

.text.CC_PalWaitInterruptRND

0x0004bb60 0x2c /opt/ncs/v2.9.1/nrfxlib/crypto/nrf_cc310_platform/lib/cortex-m4/soft-float/no-interrupts/libnrf_cc310_platform_0.9.19.a(cc_pal_interrupt_ctrl.c.obj)

0x0004bb60 CC_PalWaitInterruptRND

.text.CC_PalWaitInterrupt

0x0004bb8c 0x18 /opt/ncs/v2.9.1/nrfxlib/crypto/nrf_cc310_platform/lib/cortex-m4/soft-float/no-interrupts/libnrf_cc310_platform_0.9.19.a(cc_pal_interrupt_ctrl.c.obj)

0x0004bb8c CC_PalWaitInterrupt

RE: Random Zephyr hangs due to RNG / Entropy

JONATHAN LL — Mon, 29 Mar 2021 15:23:42 GMT

Great thanks, will update on any new regarding the issue, i.e fix.
Regards,
Jonathan

RE: Random Zephyr hangs due to RNG / Entropy

krbvroc1 — Sat, 27 Mar 2021 19:32:12 GMT

I just added an attachment to the original post. I am not sure if it reproduce the board hang, BUT...

Running the sample illustrates that calling sys_rand32_get() when the default CC310 cryptocell is used for RNG takes FOREVER. Generating 200 numbers takes over 18 seconds! There is an overlay file included, which comments out the override to the RNG. If you enable the RNG it works fine and generation time is minimal.

RE: Random Zephyr hangs due to RNG / Entropy

JONATHAN LL — Fri, 26 Mar 2021 09:49:17 GMT

Thanks for the information, we are trying to reproduce this locally. Could you possibly share a minimal project that still reproduces the issue you are seeing?
Regards,
Jonathan

RE: Random Zephyr hangs due to RNG / Entropy

krbvroc1 — Thu, 25 Mar 2021 14:35:55 GMT

I am currently using 1.5 ... I also had the same problem on the latest 'master' (1.5.99).

A workaround I was given from a Zephyr developer was to override the DTS file, basically changing

'zephyr,entropy = &cryptocell;'

'zephyr,entropy = &rng;'

Disabling the CC310 definitely fixes the issue, so there is still a bug in CC310 RNG or a regression that Nordic needs to address.

RE: Random Zephyr hangs due to RNG / Entropy

JONATHAN LL — Thu, 25 Mar 2021 14:26:42 GMT

It could be related to the issue here : [nrf52840] device hangs when reinitializing cc310 · Issue #2898 · openthread/openthread · GitHub
What version of NCS are you on ?
Regards,
Jonathan

RE: Random Zephyr hangs due to RNG / Entropy

JONATHAN LL — Wed, 24 Mar 2021 15:01:01 GMT

Hi,

Looking in to this, will update you.

Can you share your prj.conf

Regards,
Jonathan