Add process_info binary_full that provides more details #10265

michalmuskala · 2025-10-07T10:18:24Z

In particular, this includes the full original binary and all the references. Gathering this information requires full heap traversal, so is fairly expensive - that's why we keep both the existing binary and this new API.

Example:

1> A = <<0:(1024*8)>>.
2> <<B:550/bitstring,D:550/bits,E:550/bits,C/bitstring>> = A.
3> erlang:process_info(self(),[binary_full]).
[{binary_full,[{126812357133856,1024,1,
           <<0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,...>>,
           [{1100,1650},{550,1100},{1650,8192},{0,550},{0,8192}]}]}]

Original draft implementation by @garazdawi in garazdawi@d5a2c6f.

github-actions · 2025-10-07T10:19:13Z

CT Test Results

3 files 135 suites 49m 9s ⏱️
1 651 tests 1 594 ✅ 57 💤 0 ❌
2 287 runs 2 211 ✅ 76 💤 0 ❌

Results for commit 44c22ec.

♻️ This comment has been updated with latest results.

To speed up review, make sure that you have read Contributing to Erlang/OTP and that all checks pass.

See the TESTING and DEVELOPMENT HowTo guides for details about how to run test locally.

Artifacts

// Erlang/OTP Github Action Bot

In particular, this includes the full original binary and all the references. Gathering this information requires full heap traversal, so is fairly expensive - that's why we keep both the existing `binary` and this new API. Example: ``` 1> A = <<0:(1024*8)>>. 2> <<B:550/bitstring,D:550/bits,E:550/bits,C/bitstring>> = A. 3> erlang:process_info(self(),[binary_full]). [{binary_full,[{126812357133856,1024,1, <<0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,...>>, [{1100,1650},{550,1100},{1650,8192},{0,550},{0,8192}]}]}] ``` Co-authored-by: Lukas Backström <lukas@erlang.org>

jhogberg

Thanks for the PR! I've left some comments below.

erts/emulator/beam/erl_gc.c

michalmuskala · 2025-10-15T16:24:12Z

Thank you for the review. I pushed an update addressing your comments.
I also moved the read of the reference count to happen before we bump it, so we don't need to later decrease it.

jhogberg · 2025-10-27T10:00:47Z

We got a few core dumps relating to this, as well as some valgrind/asan issues.

Thread 1 (Thread 0x7f4a45fd8700 (LWP 16829)):
#0  gather_binaries (range_infos=range_infos@entry=0x7f4a45fd2b70, count=count@entry=2, start=, stop=) at beam/erl_gc.c:3860
#1  0x000055830fcb2301 in erts_gather_binaries (hfact=hfact@entry=0x7f4a45fd3a50, rp=rp@entry=0x558311d694c0) at beam/erl_gc.c:3923
#2  0x000055830fb968a2 in process_info_aux (c_p=c_p@entry=0x558311d694c0, hfact=hfact@entry=0x7f4a45fd3a50, rp=rp@entry=0x558311d694c0, rp_locks=rp_locks@entry=1, item_ix=41, extra=extra@entry=0, msgq_len_p=0x7f4a45fd37f0, flags=25, reserve_sizep=0x7f4a45fd39b0, reds=0x7f4a45fd3a48) at beam/erl_bif_info.c:2164
#3  0x000055830fb98f0a in erts_process_info (c_p=c_p@entry=0x558311d694c0, hfact=hfact@entry=0x7f4a45fd3a50, rp=rp@entry=0x558311d694c0, rp_locks=rp_locks@entry=1, item_ix=item_ix@entry=0x7f4a45fd3ac0, item_extra=item_extra@entry=0x0, item_len=1, flags=25, reserve_size=, reds=0x7f4a45fd3a48) at beam/erl_bif_info.c:1111
#4  0x000055830fb9ac4a in process_info_bif (c_p=, pid=, opt=, always_wrap=, pi2=) at beam/erl_bif_info.c:1419
#5  0x000055830faa2f40 in beam_jit_call_bif (c_p=0x558311d694c0, reg=0x7f4a45fd3d80, I=, vbf=, arity=2) at beam/jit/beam_jit_common.cpp:597
#6  0x00007f4a4a9884fa in global::call_bif_shared ()
#7  0x00007f4a4aa12a74 in erts_internal:await_result/1 ()
#8  0x00007f4a4fb187e8 in ?? ()
#9  0x00007f4a4fb187e8 in ?? ()
#10 0x0000000000000000 in ?? ()

 Testcase: process_SUITE:process_info_2_list/1 (14 errors ):

     Error[0x1a69bde]:UninitCondition: erl_gc.c:3854
         Conditional jump or move depends on uninitialised value(s)
         Suspected: gather_binaries:3854 (-> 0x4F8784) [erl_gc.c]
         Stackdump:
             gather_binaries:3854 (-> 0x4F8784) [erl_gc.c]
             erts_gather_binaries:3923 (-> 0x4FF9B1) [erl_gc.c]
             process_info_aux:2164 (-> 0x424347) [erl_bif_info.c]
             erts_process_info:1111 (-> 0x424B1F) [erl_bif_info.c]
             process_info_bif:1419 (-> 0x425F98) [erl_bif_info.c]
             process_info_2:1559 (-> 0x426A1F) [erl_bif_info.c]
             beam_jit_call_bif(process*, unsigned long*, void const*, unsigned long (*)(process*, unsigned long*, void const*), unsigned long):597 (-> 0x33A09F) [beam_jit_common.cpp]
             $global::call_bif_shared+46:??? (-> 0x46D0552E) [JIT code]
             $global::i_breakpoint_trampoline_shared+2B:??? (-> 0x46D06083) [JIT code]
             $erts_internal:await_result/1+63:??? (-> 0x46D9A84B) [JIT code]
             :??? (-> 0x4BE2BD3F) []
             $erts_internal:await_result/1+133:??? (-> 0x46D9A91B) [JIT code]

 Error[0x1a69dce]:UninitValue: erl_gc.c:3852

     Use of uninitialised value of size 8
     Suspected: gather_binaries:3852 (-> 0x4F877B) [erl_gc.c]
     Stackdump:
         gather_binaries:3852 (-> 0x4F877B) [erl_gc.c]
         erts_gather_binaries:3923 (-> 0x4FF9B1) [erl_gc.c]
         process_info_aux:2164 (-> 0x424347) [erl_bif_info.c]
         erts_process_info:1111 (-> 0x424B1F) [erl_bif_info.c]
         process_info_bif:1419 (-> 0x425F98) [erl_bif_info.c]
         process_info_2:1559 (-> 0x426A1F) [erl_bif_info.c]
         beam_jit_call_bif(process*, unsigned long*, void const*, unsigned long (*)(process*, unsigned long*, void const*), unsigned long):597 (-> 0x33A09F) [beam_jit_common.cpp]
         $global::call_bif_shared+46:??? (-> 0x46D0552E) [JIT code]
         $global::i_breakpoint_trampoline_shared+2B:??? (-> 0x46D06083) [JIT code]
         $erts_internal:await_result/1+63:??? (-> 0x46D9A84B) [JIT code]
         :??? (-> 0x4BE2BD3F) []
         $erts_internal:await_result/1+133:??? (-> 0x46D9A91B) [JIT code]

 Error[0x1a6a47f]:UninitCondition: erl_gc.c:3857

     Conditional jump or move depends on uninitialised value(s)
     Suspected: gather_binaries:3857 (-> 0x4F8793) [erl_gc.c]
     Stackdump:
         gather_binaries:3857 (-> 0x4F8793) [erl_gc.c]
         erts_gather_binaries:3923 (-> 0x4FF9B1) [erl_gc.c]
         process_info_aux:2164 (-> 0x424347) [erl_bif_info.c]
         erts_process_info:1141 (-> 0x424BFE) [erl_bif_info.c]
         process_info_bif:1419 (-> 0x425F98) [erl_bif_info.c]
         process_info_2:1559 (-> 0x426A1F) [erl_bif_info.c]
         beam_jit_call_bif(process*, unsigned long*, void const*, unsigned long (*)(process*, unsigned long*, void const*), unsigned long):597 (-> 0x33A09F) [beam_jit_common.cpp]
         $global::call_bif_shared+46:??? (-> 0x46D0552E) [JIT code]
         $global::i_breakpoint_trampoline_shared+2B:??? (-> 0x46D06083) [JIT code]
         $erts_internal:await_result/1+63:??? (-> 0x46D9A84B) [JIT code]
         :??? (-> 0x4BE2BD3F) []
         $erts_internal:await_result/1+133:??? (-> 0x46D9A91B) [JIT code]


 Error[0x1a6a480]:UninitCondition: erl_gc.c:3870

     Conditional jump or move depends on uninitialised value(s)
     Suspected: gather_binaries:3870 (-> 0x4F87A3) [erl_gc.c]
     Stackdump:
         gather_binaries:3870 (-> 0x4F87A3) [erl_gc.c]
         erts_gather_binaries:3923 (-> 0x4FF9B1) [erl_gc.c]
         process_info_aux:2164 (-> 0x424347) [erl_bif_info.c]
         erts_process_info:1141 (-> 0x424BFE) [erl_bif_info.c]
         process_info_bif:1419 (-> 0x425F98) [erl_bif_info.c]
         process_info_2:1559 (-> 0x426A1F) [erl_bif_info.c]
         beam_jit_call_bif(process*, unsigned long*, void const*, unsigned long (*)(process*, unsigned long*, void const*), unsigned long):597 (-> 0x33A09F) [beam_jit_common.cpp]
         $global::call_bif_shared+46:??? (-> 0x46D0552E) [JIT code]
         $global::i_breakpoint_trampoline_shared+2B:??? (-> 0x46D06083) [JIT code]
         $erts_internal:await_result/1+63:??? (-> 0x46D9A84B) [JIT code]
         :??? (-> 0x4BE2BD3F) []
         $erts_internal:await_result/1+133:??? (-> 0x46D9A91B) [JIT code]

 Error[0x1a6a482]:UninitCondition: erl_gc.c:3851

     Conditional jump or move depends on uninitialised value(s)
     Suspected: gather_binaries:3851 (-> 0x4F8775) [erl_gc.c]
     Stackdump:
         gather_binaries:3851 (-> 0x4F8775) [erl_gc.c]
         erts_gather_binaries:3923 (-> 0x4FF9B1) [erl_gc.c]
         process_info_aux:2164 (-> 0x424347) [erl_bif_info.c]
         erts_process_info:1141 (-> 0x424BFE) [erl_bif_info.c]
         process_info_bif:1419 (-> 0x425F98) [erl_bif_info.c]
         process_info_2:1559 (-> 0x426A1F) [erl_bif_info.c]
         beam_jit_call_bif(process*, unsigned long*, void const*, unsigned long (*)(process*, unsigned long*, void const*), unsigned long):597 (-> 0x33A09F) [beam_jit_common.cpp]
         $global::call_bif_shared+46:??? (-> 0x46D0552E) [JIT code]
         $global::i_breakpoint_trampoline_shared+2B:??? (-> 0x46D06083) [JIT code]
         $erts_internal:await_result/1+63:??? (-> 0x46D9A84B) [JIT code]
         :??? (-> 0x4BE2BD3F) []
         $erts_internal:await_result/1+133:??? (-> 0x46D9A91B) [JIT code]

jhogberg · 2025-10-27T10:14:43Z

Core was generated by `/ldisk/daily_build/29_master-opu_o.2025-10-25_21/otp/lib/erlang/erts-16.2/bin/be'.
Program terminated with signal SIGBUS, Bus error.
Object-specific hardware error.
#0  gather_binaries (range_infos=0x871926c80, count=4, start=, stop=0x914f71bd058) at beam/erl_gc.c:3860
3860	                if (thing_subtag(underlying->thing_word) != HEAP_BITS_SUBTAG) {
[Current thread is 1 (LWP 1091786)]

Core was generated by `/ldisk/daily_build/29_master-opu_o_inet_backend.2025-10-24_21/otp/lib/erlang/er'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  gather_binaries (range_infos=range_infos@entry=0x7fcfe5d09b20, count=count@entry=2, start=, stop=0x7fcfa25db2f8) at beam/erl_gc.c:3860
3860	                if (thing_subtag(underlying->thing_word) != HEAP_BITS_SUBTAG) {
[Current thread is 1 (Thread 0x7fcfe5d0f6c0 (LWP 954920))]

michalmuskala · 2025-10-27T14:44:35Z

Thanks, I'll take a look

michalmuskala force-pushed the binary-full branch 5 times, most recently from eb25eca to 1ca8340 Compare October 7, 2025 12:07

michalmuskala force-pushed the binary-full branch from 1ca8340 to 39c06bb Compare October 7, 2025 12:09

IngelaAndin added the team:VM Assigned to OTP team VM label Oct 13, 2025

jhogberg self-assigned this Oct 13, 2025

jhogberg reviewed Oct 15, 2025

View reviewed changes

fixup: apply code review

263de82

michalmuskala force-pushed the binary-full branch from bfb2d9e to 263de82 Compare October 15, 2025 16:23

fixup: more const

44c22ec

jhogberg added testing currently being tested, tag is used by OTP internal CI and removed testing currently being tested, tag is used by OTP internal CI labels Oct 23, 2025

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Uh oh!

Add process_info binary_full that provides more details #10265

Add process_info binary_full that provides more details #10265

michalmuskala commented Oct 7, 2025

Uh oh!

github-actions bot commented Oct 7, 2025 •

edited

Loading

Uh oh!

jhogberg left a comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

michalmuskala commented Oct 15, 2025

Uh oh!

jhogberg commented Oct 27, 2025

Uh oh!

jhogberg commented Oct 27, 2025 •

edited

Loading

Uh oh!

michalmuskala commented Oct 27, 2025

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

Uh oh!

Add process_info binary_full that provides more details #10265

Are you sure you want to change the base?

Add process_info binary_full that provides more details #10265

Conversation

michalmuskala commented Oct 7, 2025

Uh oh!

github-actions bot commented Oct 7, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

CT Test Results

Artifacts

Uh oh!

jhogberg left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

michalmuskala commented Oct 15, 2025

Uh oh!

jhogberg commented Oct 27, 2025

Uh oh!

jhogberg commented Oct 27, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

michalmuskala commented Oct 27, 2025

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

github-actions bot commented Oct 7, 2025 •

edited

Loading

jhogberg commented Oct 27, 2025 •

edited

Loading