Possible problem with timers

[HrMitrev]

Describe the bug
I'm not sure if the problem is in Zephyr or if it's because of stack overflow. Also I'm not familiar with the rtc clock nor with the zephyr kernel timeout in tickless mode. The problem always occurs when I'm reseting my gsm modem and more specifically when I'm stopping PPP.

Could someone suggest if there's a chance this to be Zephyr's issue?

Logs and console output
[ 396.882812] modem_gsm: GSM network interface down
[ 397.057403] os: ***** MPU FAULT *****
[ 397.057708] os: Data Access Violation
[ 397.057983] os: MMFAR Address: 0x0
[ 397.058288] os: r0/a1: 0x20021928 r1/a2: 0x00c66dbd r2/a3: 0x00000000
[ 397.058776] os: r3/a4: 0x00000000 r12/ip: 0x00000000 r14/lr: 0x00021715
[ 397.059204] os: xpsr: 0x21000221
[ 397.059509] os: Faulting instruction address (r15/pc): 0x00021538
[ 397.059906] os: >>> ZEPHYR FATAL ERROR 0: CPU exception on CPU 0
[ 397.060302] os: Fault during interrupt handling

[ 397.060638] os: Current thread: 0x20006ee8 (unknown)
[ 397.065948] os: Halting system

(gdb) c
Continuing.

^C
Program received signal SIGTRAP, Trace/breakpoint trap.
arch_system_halt (reason=reason@entry=0) at /home/hrm/git/zephyr_sdk/zephyr/kernel/fatal.c:32
32		}
(gdb) bt
#0  arch_system_halt (reason=reason@entry=0) at /home/hrm/git/zephyr_sdk/zephyr/kernel/fatal.c:32
#1  0x0002024a in k_sys_fatal_error_handler (reason=reason@entry=0, esf=esf@entry=0x2001e240 <z_interrupt_stacks+1856>) at /home/hrm/git/zephyr_sdk/zephyr/kernel/fatal.c:44
#2  0x000202ea in z_fatal_error (reason=reason@entry=0, esf=esf@entry=0x2001e240 <z_interrupt_stacks+1856>) at /home/hrm/git/zephyr_sdk/zephyr/kernel/fatal.c:127
#3  0x000047e0 in z_arm_fatal_error (reason=reason@entry=0, esf=esf@entry=0x2001e240 <z_interrupt_stacks+1856>) at /home/hrm/git/zephyr_sdk/zephyr/arch/arm/core/aarch32/fatal.c:63
#4  0x00004ed4 in z_arm_fault (msp=<optimized out>, psp=<optimized out>, exc_return=<optimized out>, callee_regs=<optimized out>) at /home/hrm/git/zephyr_sdk/zephyr/arch/arm/core/aarch32/cortex_m/fault.c:1060
#5  0x00004fec in z_arm_usage_fault () at /home/hrm/git/zephyr_sdk/zephyr/arch/arm/core/aarch32/cortex_m/fault_s.S:102
#6  <signal handler called>
#7  sys_dlist_remove (node=0x20021928 <_k_mem_slab_buf_tcp_conns_slab+1928>) at /home/hrm/git/zephyr_sdk/zephyr/include/sys/dlist.h:501
#8  remove_timeout (t=t@entry=0x20021928 <_k_mem_slab_buf_tcp_conns_slab+1928>) at /home/hrm/git/zephyr_sdk/zephyr/kernel/timeout.c:59
#9  0x00021714 in sys_clock_announce (ticks=<optimized out>) at /home/hrm/git/zephyr_sdk/zephyr/kernel/timeout.c:256
#10 0x0001553e in sys_clock_timeout_handler (chan=0, expire_time=<optimized out>, user_data=0x0 <z_log_msg2_runtime_create>) at /home/hrm/git/zephyr_sdk/zephyr/drivers/timer/nrf_rtc_timer.c:421
#11 0x000158ac in process_channel (chan=0) at /home/hrm/git/zephyr_sdk/zephyr/drivers/timer/nrf_rtc_timer.c:493
#12 rtc_nrf_isr (arg=<optimized out>) at /home/hrm/git/zephyr_sdk/zephyr/drivers/timer/nrf_rtc_timer.c:517
#13 0x00004a3a in _isr_wrapper () at /home/hrm/git/zephyr_sdk/zephyr/arch/arm/core/aarch32/isr_wrapper.S:234
#14 <signal handler called>
#15 0x3c969a6a in ?? ()
#16 0xf399816c in ?? ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
(gdb) bt full
#0  arch_system_halt (reason=reason@entry=0) at /home/hrm/git/zephyr_sdk/zephyr/kernel/fatal.c:32
No locals.
#1  0x0002024a in k_sys_fatal_error_handler (reason=reason@entry=0, esf=esf@entry=0x2001e240 <z_interrupt_stacks+1856>) at /home/hrm/git/zephyr_sdk/zephyr/kernel/fatal.c:44
No locals.
#2  0x000202ea in z_fatal_error (reason=reason@entry=0, esf=esf@entry=0x2001e240 <z_interrupt_stacks+1856>) at /home/hrm/git/zephyr_sdk/zephyr/kernel/fatal.c:127
        key = 0
        thread = 0x20006ee8 <z_idle_threads>
#3  0x000047e0 in z_arm_fatal_error (reason=reason@entry=0, esf=esf@entry=0x2001e240 <z_interrupt_stacks+1856>) at /home/hrm/git/zephyr_sdk/zephyr/arch/arm/core/aarch32/fatal.c:63
No locals.
#4  0x00004ed4 in z_arm_fault (msp=<optimized out>, psp=<optimized out>, exc_return=<optimized out>, callee_regs=<optimized out>) at /home/hrm/git/zephyr_sdk/zephyr/arch/arm/core/aarch32/cortex_m/fault.c:1060
        reason = 0
        fault = 0
        recoverable = false
        nested_exc = true
        esf = 0x2001e288 <z_interrupt_stacks+1928>
        esf_copy = {basic = {{a1 = 537008424, r0 = 537008424}, {a2 = 13004221, r1 = 13004221}, {a3 = 0, r2 = 0}, {a4 = 0, r3 = 0}, {ip = 0, r12 = 0}, {lr = 136981, r14 = 136981}, {pc = 136504, r15 = 136504}, xpsr = 553648673}}
#5  0x00004fec in z_arm_usage_fault () at /home/hrm/git/zephyr_sdk/zephyr/arch/arm/core/aarch32/cortex_m/fault_s.S:102
No locals.
#6  <signal handler called>
No symbol table info available.
#7  sys_dlist_remove (node=0x20021928 <_k_mem_slab_buf_tcp_conns_slab+1928>) at /home/hrm/git/zephyr_sdk/zephyr/include/sys/dlist.h:501
        prev = 0x0 <z_log_msg2_runtime_create>
        next = 0x0 <z_log_msg2_runtime_create>
#8  remove_timeout (t=t@entry=0x20021928 <_k_mem_slab_buf_tcp_conns_slab+1928>) at /home/hrm/git/zephyr_sdk/zephyr/kernel/timeout.c:59
No locals.
#9  0x00021714 in sys_clock_announce (ticks=<optimized out>) at /home/hrm/git/zephyr_sdk/zephyr/kernel/timeout.c:256
        t = 0x20021928 <_k_mem_slab_buf_tcp_conns_slab+1928>
        dt = <optimized out>
        key = {key = 0}
#10 0x0001553e in sys_clock_timeout_handler (chan=0, expire_time=<optimized out>, user_data=0x0 <z_log_msg2_runtime_create>) at /home/hrm/git/zephyr_sdk/zephyr/drivers/timer/nrf_rtc_timer.c:421
        cc_value = 13010777
        dticks = <optimized out>
        anchor_updated = true
#11 0x000158ac in process_channel (chan=0) at /home/hrm/git/zephyr_sdk/zephyr/drivers/timer/nrf_rtc_timer.c:493
        expire_time = 13010777
        user_context = 0x0 <z_log_msg2_runtime_create>
        mcu_critical_state = <optimized out>
        curr_time = <optimized out>
        handler = <optimized out>
#12 rtc_nrf_isr (arg=<optimized out>) at /home/hrm/git/zephyr_sdk/zephyr/drivers/timer/nrf_rtc_timer.c:517
        chan = 0
#13 0x00004a3a in _isr_wrapper () at /home/hrm/git/zephyr_sdk/zephyr/arch/arm/core/aarch32/isr_wrapper.S:234
No locals.
#14 <signal handler called>
No symbol table info available.
#15 0x3c969a6a in ?? ()
No symbol table info available.
#16 0xf399816c in ?? ()
No symbol table info available.
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
(gdb)

Environment (please complete the following information):

Latest zephyr as of now - commit de55106

[mbolivar-nordic]

Hi, this is not enough information to consider this a bug so I have converted it to a discussion.

Please provide more detailed steps to reproduce.