Hello.
I'm looking for some advice debugging what I think is a race condition around bt_le_per_adv_sync_delete.
After calling bt_le_per_adv_sync_delete, we're sometimes seeing an Illegal load of EXC_RETURN into PC fault.
[00:05:18.404,205] <err> os: ***** USAGE FAULT ***** [00:05:18.404,205] <err> os: Illegal load of EXC_RETURN into PC [00:05:18.404,235] <err> os: r0/a1: 0x00000000 r1/a2: 0x0006ca19 r2/a3: 0x00000091 [00:05:18.404,235] <err> os: r3/a4: 0x00000003 r12/ip: 0x00000002 r14/lr: 0x2000764c [00:05:18.404,266] <err> os: xpsr: 0x0003ee00 [00:05:18.404,266] <err> os: s[ 0]: 0x2000fbc8 s[ 1]: 0x2000fbc8 s[ 2]: 0x20018068 s[ 3]: 0x000a39e9 [00:05:18.404,296] <err> os: s[ 4]: 0x000a39d7 s[ 5]: 0x0008be7b s[ 6]: 0xffffffff s[ 7]: 0xffffffff [00:05:18.404,296] <err> os: s[ 8]: 0x00000000 s[ 9]: 0x00000000 s[10]: 0x0008bde9 s[11]: 0x00000000 [00:05:18.404,327] <err> os: s[12]: 0x00000000 s[13]: 0x00000000 s[14]: 0x00000000 s[15]: 0x0009b273 [00:05:18.404,327] <err> os: fpscr: 0x00000000 [00:05:18.404,357] <err> os: r4/v1: 0x00000000 r5/v2: 0x00000000 r6/v3: 0xffffffff [00:05:18.404,357] <err> os: r7/v4: 0xffffffff r8/v5: 0x00000000 r9/v6: 0x00000000 [00:05:18.404,388] <err> os: r10/v7: 0x00000000 r11/v8: 0x00000000 psp: 0x20022518 [00:05:18.404,388] <err> os: EXC_RETURN: 0xfffffffd [00:05:18.404,388] <err> os: Faulting instruction address (r15/pc): 0x20019e24 [00:08:00.736,022] <err> os: >>> ZEPHYR FATAL ERROR 34: Unknown error on CPU 0 [00:08:00.736,053] <err> os: Current thread: 0x2000fbc8 (MPSL Work) [00:08:01.752,288] <err> fatal_error: Resetting system
It's difficult to trigger, but when I have achieved it, traces are showing that it's happening somewhere around `pending_cancels` on the MPSL workqueue. Unfortunately I don't seem to have debug symbols to be able to look further into the fault.
