Test Failure: System.Text.Encodings.Web.Tests

[kg]

Summary:
System.Text.Encodings.Web.Tests crashes with SIGSEGV (exit 139) on linux-arm (Debian 13 arm32v7 docker container, fullpgo configuration) during xunit test discovery/startup. The native crash report contains only unresolved frames (no symbols on arm32).

Failed in (1):

• runtime-coreclr libraries-pgo 20260517.1

Console Log: Console Log
Source: runtime-coreclr libraries-pgo / net11.0-linux-Release-arm-fullpgo-(Debian.13.Arm32.Open)AzureLinux.3.Arm64.Open@mcr.microsoft.com/dotnet-buildtools/prereqs:debian-13-helix-arm32v7@sha256:9ee81df17d6a4bf96b7b2f785a1352a3a762aec2a01b2bb8ffd691520aad7dee / System.Text.Encodings.Web.Tests

Failed tests:

- net11.0-linux-Release-arm-fullpgo-(Debian.13.Arm32.Open)AzureLinux.3.Arm64.Open@mcr.microsoft.com/dotnet-buildtools/prereqs:debian-13-helix-arm32v7@sha256:9ee81df17d6a4bf96b7b2f785a1352a3a762aec2a01b2bb8ffd691520aad7dee
  - System.Text.Encodings.Web.Tests

Error Message:

  Discovered:  System.Text.Encodings.Web.Tests (found 201 test cases)
  Starting:    System.Text.Encodings.Web.Tests (parallel test collections = on [2 threads], stop on fail = off)
[createdump] Gathering state for process 20 dotnet
[createdump] Crashing thread 0021 signal 11 (000b)
[createdump] Writing crash report to file /datadisks/disk1/dumps/coredump.20.dmp.crashreport.json
[createdump] Crash report successfully written
[createdump] Writing minidump with heap to file /datadisks/disk1/dumps/coredump.20.dmp
[createdump] Written 137125888 bytes (33478 pages) to core file
[createdump] Target process is alive
[createdump] Dump successfully written in 230ms
waitpid() returned successfully (wstatus 00000000) WEXITSTATUS 0 WTERMSIG 0
./RunTests.sh: line 175:    20 Segmentation fault      (core dumped) "$RUNTIME_PATH/dotnet" exec --runtimeconfig System.Text.Encodings.Web.Tests.runtimeconfig.json --depsfile System.Text.Encodings.Web.Tests.deps.json xunit.console.dll System.Text.Encodings.Web.Tests.dll -xml testResults.xml -nologo -nocolor -notrait category=IgnoreForCI -notrait category=OuterLoop -notrait category=failing $RSP_FILE
/root/helix/work/workitem/e
----- end Sun May 17 04:48:25 PM UTC 2026 ----- exit code 139 ----------------------------------------------------------
exit code 139 means SIGSEGV Illegal memory access. Deref invalid pointer, overrunning buffer, stack overflow etc. Core dumped.

Stack Trace:

N/A

Analysis:
No matching open or closed GitHub issue found via search passes for: "Encodings.Web fullpgo arm", "System.Text.Encodings.Web.Tests SIGSEGV fullpgo arm", "Encodings.Web libraries-pgo crash". Distinct from older closed wasm/mono Encodings.Web issues (#100850, #50965). Appears to be a NEW failure — likely an arm32-specific PGO codegen bug.

Generated by ci-pipeline-monitor/scripts/update_github.py

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[tarekgh]

This looks more codegen issue?

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