Bug #5125

segfault in pdch_ul_controller.c:pdch_ulc_get_node()

Added by keith 23 days ago. Updated 22 days ago.

Target version:
Start date:
Due date:
% Done:


Spec Reference:


Program received signal SIGSEGV, Segmentation fault.
pdch_ulc_get_node (ulc=<optimized out>, fn=fn@entry=95849) at /usr/src/debug/osmo-pcu/0.9.0+gitAUTOINC+16e1678bfc-r0.18/git/src/pdch_ul_controller.c:75

[Binary from nightly today Tue 20th April.]

osmo-pcu is most of the time crashing within a few seconds of start up

Attached is a capture of startup and debugging session. due to getting <opimized out> in gdb I went back up the trace to look for relevant data.

I think this might be relevant?:

(gdb) p *bts->trx[0].pdch[5]->ulc
$12 = {pdch = 0x2b2b2b2b, last_fn = 724249387, tree_root = {rb_node = 0x2b2b2b2b}, pool_ctx = 0x2b2b2b2b}
screen.txt screen.txt 152 KB keith, 04/20/2021 09:25 PM


#1 Updated by keith 23 days ago

  • Status changed from New to Feedback
  • Assignee set to keith
  • Priority changed from High to Low

Actually.. forget it, I realise this might have to do with not running latest osmo-bts.

#2 Updated by fixeria 23 days ago

$12 = {pdch = 0x2b2b2b2b, last_fn = 724249387, tree_root = {rb_node = 0x2b2b2b2b}, pool_ctx = 0x2b2b2b2b}

I first paid my attention to 0x2b2b2b2b. Is it just a funny coincidence? Or do deal with a buffer overflow, and somehow osmo-pcu writes MAC block padding to the pointers? keith you can try to compile osmo-pcu with --enable-sanitize, so we can see if my assumption is correct.

#3 Updated by pespin 23 days ago

Please make sure you first have master of all components.

That's running osmo-pcu-sysmo? that is, with direct phy, correct?

#4 Updated by pespin 23 days ago

I just tested on my sysmobts running 20175-nightly I just updated, and everything is looking fine here, I have one MS pinging over EGPRS without problems/crashes.

Please also provide the TS layout config of your BTS/PCU.

#5 Updated by keith 22 days ago

  • Status changed from Feedback to Rejected

As I said, I realised I was not running it against master osmo-bts and I saw commits there that are probably related.

Yes it was osmo-bts-sysmo with direct phy but not the latest osmo-bts.

I'm closing this as invalid, thanks for the attention, but sorry for wasting your time.

That said,I do often see errors with a variety of 1,000 MS that I don't see with one phone on my desk pinging.
If I see this again with full master, I'll open another ticket.

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