Crash on libquic.dylib (com.apple.network.connections) EXC_BREAKPOINT (SIGTRAP)

We've started seeing the same in our apps. For users that are impacted by it, it seems to happen a lot.

It’s possible that this is a known bug (r. 84641488). If so, it’s not fixed in any currently seeded iOS 15 release (right now that’s iOS 15.2b1, 19C5026i) but, as always, I recommend that you retest as new releases are seeded.

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Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

Yes, this is an issue we are seeing across a number of our applications and is currently the number one cause of crashes we are seeing.

Also seeing this crash occur frequently on devices running iOS 15.1 (doesn't seem to appear in 15.0). @eskimo you mentioned it might be a known bug that a radar exists for but I'm unable to find anything using the radar id you provided. I know these reports are intentionally kept private but is there somewhere we can track progress/possible workarounds on this known bug? Thanks in advance.

is there somewhere we can track progress/possible workarounds on this known bug?

Not really. You could file a new bug and ask that it be dup’d to the one I mentioned. That will give you minimal status info about the issue, that is, whether it’s still open or closed. However, I don’t think that’s worth the effort. I stand by my earlier advice, namely, that you should monitor upcoming iOS beta releases as they are seeded.

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—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

I stand by my earlier advice, namely, that you should monitor upcoming iOS beta releases as they are seeded.

And, of course, as soon as I posted this we started seeding iOS 15.2b2 (19C5036e). AFAICT this does not have the fix for this bug (r. 84641488).

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—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

Have the same crash on our apps and is currently the number one cause of crashes we are seeing, really hope it can be fixed ASAP.

This is also the #1 crash we're seeing on our app. Hoping there's a fix soon as well.

iOS 15.2b2 (19C5036e) … does not have the fix for this bug (r. 84641488).

Yesterday we started seeding iOS 15.2b3 (19C5044b). My understanding is that this includes the fix for this bug (yay!). Please let us know if you see any evidence to the contrary.

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—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

We have the same crash, more and more users have encountered this issue. This crash happens 100% on iOS 15, including iPadOS 15. Here is the crash log from Firebase. How to fix this please??

Crashed: com.apple.network.connections
SIGTRAP 0x00000001f2566938

Crashed: com.apple.network.connections
0  libquic.dylib                  0x69938 qlog_abort_internal
1  libquic.dylib                  0x69924 qlog_abort_internal
2  libquic.dylib                  0x639e4 quic_frame_write_PADDING
3  libquic.dylib                  0x9c6dc _quic_packet_builder_assemble
4  libquic.dylib                  0x2490 quic_packet_builder_assemble
5  libquic.dylib                  0x366bc quic_assemble_and_encrypt
6  libquic.dylib                  0x37a04 __quic_send_frames_for_key_state_block_invoke.106
7  libnetwork.dylib               0x603310 nw_protocol_data_access_buffer + 1160
8  libquic.dylib                  0x1c8c8 __quic_send_frames_for_key_state_block_invoke
9  libnetwork.dylib               0xb9d4 nw_protocol_service_requested_outbound_data + 360
10 libnetwork.dylib               0x5e99fc nw_protocol_request_outbound_data + 128
11 libquic.dylib                  0x22cb8 quic_send_frames_for_key_state
12 libquic.dylib                  0x18f48 _quic_send_frames_with_override
13 libquic.dylib                  0x56710 quic_frame_process_PATH_CHALLENGE
14 libquic.dylib                  0x63c50 quic_frame_process
15 libquic.dylib                  0x165f4 quic_process_inbound
16 libnetwork.dylib               0x603310 nw_protocol_data_access_buffer + 1160
17 libquic.dylib                  0x15400 __quic_handle_inbound_block_invoke
18 libquic.dylib                  0x1198 quic_handle_inbound
19 libnetwork.dylib               0x5e3918 __nw_protocol_implementation_get_input_internal_block_invoke + 136
20 libnetwork.dylib               0x5e2930 nw_protocol_implementation_get_input_internal + 252
21 libnetwork.dylib               0x5e19bc nw_protocol_implementation_read + 392
22 libnetwork.dylib               0x5e1040 nw_protocol_implementation_input_available + 96
23 libnetwork.dylib               0x52f608 nw_channel_add_input_frames + 9404
24 libnetwork.dylib               0x52d05c nw_channel_update_input_source + 324
25 libnetwork.dylib               0x52c274 __nw_channel_create_block_invoke.29 + 72
26 libdispatch.dylib              0x4660 _dispatch_client_callout + 20
27 libdispatch.dylib              0x7b34 _dispatch_continuation_pop + 504
28 libdispatch.dylib              0x1ac38 _dispatch_source_invoke + 1356
29 libdispatch.dylib              0xdc74 _dispatch_workloop_invoke + 1796
30 libdispatch.dylib              0x171a8 _dispatch_workloop_worker_thread + 656
31 libsystem_pthread.dylib        0x10f4 _pthread_wqthread + 288
32 libsystem_pthread.dylib        0xe94 start_wqthread + 8

We have the same crash

Have you seen it on iOS 15.2b3 (19C5044b) or later?

[Well, there is no “later” right now, but I’m writing this in the expectation that there will be at some point.]

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

Any fixes to this Crash?

Any fixes to this Crash?

Have you seen it on iOS 15.2b3 (19C5044b) or later?

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

Does it relate to URLSession with background configuration?

Does it relate to URLSession with background configuration?

No. The specific bug being discussed here (r. 84641488) is in the core QUIC implementation and will affect any QUIC client, including all flavours of URLSession when talking to an HTTP/3 server.

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"