getsentry
Vernier + profiling enabled causing silent crashes
Issue Description
With Vernier installed and configured as the profiler, there is a random segmentation fault encoutered inside Sentry, causing a 500 error user-facing, but no exception ever reported to Sentry. This can cause silent failures where there are no visible signs that the website is flakey other than failed requests.
I had this manifest on gemdocs.org.
From Gemfile.lock
concurrent-ruby (1.3.5)
sentry-rails (5.22.4)
railties (>= 5.0)
sentry-ruby (~> 5.22.4)
sentry-ruby (5.22.4)
bigdecimal
concurrent-ruby (~> 1.0, >= 1.0.2)
vernier (1.5.0)
Stacktrace
[9403b-a7c0-4727-b91c-e3518d748965] Started GET "/gems/datadog_api_client/2.23.0/DatadogAPIClient/V2/RUMApplicationCreateRequest.html" for 37.19.207.34 at 2025-02-23 04:27:54 +0000
/app/vendor/bundle/ruby/3.4.0/gems/vernier-1.5.0/lib/vernier/collector.rb:77: [BUG] Segmentation fault at 0x0000000000000000
ruby 3.4.1 (2024-12-25 revision 48d4efcb85) +YJIT +PRISM [x86_64-linux]
-- Control frame information -----------------------------------------------
c:0036 p:---- s:0243 e:000242 CFUNC :finish
c:0035 p:0003 s:0239 e:000238 METHOD /app/vendor/bundle/ruby/3.4.0/gems/vernier-1.5.0/lib/vernier/collector.rb:77
c:0034 p:0016 s:0231 e:000230 METHOD /app/vendor/bundle/ruby/3.4.0/gems/vernier-1.5.0/lib/vernier.rb:56
c:0033 p:0018 s:0226 e:000225 METHOD /app/vendor/bundle/ruby/3.4.0/gems/sentry-ruby-5.22.4/lib/sentry/vernier/profiler.rb:76
c:0032 p:0043 s:0221 e:000220 METHOD /app/vendor/bundle/ruby/3.4.0/gems/sentry-ruby-5.22.4/lib/sentry/transaction.rb:260
c:0031 p:0017 s:0211 e:000210 METHOD /app/vendor/bundle/ruby/3.4.0/gems/sentry-ruby-5.22.4/lib/sentry/rack/capture_exceptions.rb:83
c:0030 p:0102 s:0205 e:000204 BLOCK /app/vendor/bundle/ruby/3.4.0/gems/sentry-ruby-5.22.4/lib/sentry/rack/capture_exceptions.rb:43
c:0029 p:0020 s:0198 e:000197 METHOD /app/vendor/bundle/ruby/3.4.0/gems/sentry-ruby-5.22.4/lib/sentry/hub.rb:269
c:0028 p:0017 s:0193 e:000192 METHOD /app/vendor/bundle/ruby/3.4.0/gems/sentry-ruby-5.22.4/lib/sentry-ruby.rb:420
c:0027 p:0006 s:0188 e:000187 BLOCK /app/vendor/bundle/ruby/3.4.0/gems/sentry-ruby-5.22.4/lib/sentry/rack/capture_exceptions.rb:21
c:0026 p:0009 s:0184 e:000183 METHOD /app/vendor/bundle/ruby/3.4.0/gems/sentry-ruby-5.22.4/lib/sentry/hub.rb:59
c:0025 p:0017 s:0179 e:000178 METHOD /app/vendor/bundle/ruby/3.4.0/gems/sentry-ruby-5.22.4/lib/sentry-ruby.rb:400
c:0024 p:0024 s:0174 e:000173 METHOD /app/vendor/bundle/ruby/3.4.0/gems/sentry-ruby-5.22.4/lib/sentry/rack/capture_exceptions.rb:20
c:0023 p:0007 s:0169 e:000168 METHOD /app/vendor/bundle/ruby/3.4.0/gems/actionpack-8.0.1/lib/action_dispatch/middleware/show_exceptions.rb:32
c:0022 p:0047 s:0160 E:001a38 METHOD /app/vendor/bundle/ruby/3.4.0/gems/railties-8.0.1/lib/rails/rack/logger.rb:41
c:0021 p:0048 s:0147 e:000146 METHOD /app/vendor/bundle/ruby/3.4.0/gems/railties-8.0.1/lib/rails/rack/logger.rb:29
c:0020 p:0028 s:0141 e:000140 METHOD /app/vendor/bundle/ruby/3.4.0/gems/railties-8.0.1/lib/rails/rack/silence_request.rb:28
c:0019 p:0034 s:0136 e:000135 METHOD /app/vendor/bundle/ruby/3.4.0/gems/actionpack-8.0.1/lib/action_dispatch/middleware/remote_ip.rb:96
c:0018 p:0030 s:0130 e:000129 METHOD /app/vendor/bundle/ruby/3.4.0/gems/actionpack-8.0.1/lib/action_dispatch/middleware/request_id.rb:34
c:0017 p:0057 s:0124 e:000123 METHOD /app/vendor/bundle/ruby/3.4.0/gems/rack-3.1.9/lib/rack/method_override.rb:28
c:0016 p:0013 s:0118 e:000117 METHOD /app/vendor/bundle/ruby/3.4.0/gems/rack-3.1.9/lib/rack/runtime.rb:24
c:0015 p:0019 s:0108 e:000107 METHOD /app/vendor/bundle/ruby/3.4.0/gems/activesupport-8.0.1/lib/active_support/cache/strategy/local_cache_middleware.rb:29
c:0014 p:0016 s:0101 e:000100 METHOD /app/vendor/bundle/ruby/3.4.0/gems/actionpack-8.0.1/lib/action_dispatch/middleware/executor.rb:16
c:0013 p:0018 s:0092 e:000091 METHOD /app/vendor/bundle/ruby/3.4.0/gems/actionpack-8.0.1/lib/action_dispatch/middleware/static.rb:27
c:0012 p:0007 s:0087 e:000086 METHOD /app/vendor/bundle/ruby/3.4.0/gems/rack-3.1.9/lib/rack/sendfile.rb:114
c:0011 p:0021 s:0074 e:000073 METHOD /app/vendor/bundle/ruby/3.4.0/gems/actionpack-8.0.1/lib/action_dispatch/middleware/ssl.rb:92
c:0010 p:0043 s:0068 e:000067 METHOD /app/vendor/bundle/ruby/3.4.0/gems/actionpack-8.0.1/lib/action_dispatch/middleware/assume_ssl.rb:24
c:0009 p:0016 s:0063 e:000062 METHOD /app/vendor/bundle/ruby/3.4.0/gems/railties-8.0.1/lib/rails/engine.rb:535
c:0008 p:0017 s:0057 e:000056 METHOD /app/vendor/bundle/ruby/3.4.0/gems/puma-6.6.0/lib/puma/configuration.rb:279
c:0007 p:0007 s:0052 e:000051 BLOCK /app/vendor/bundle/ruby/3.4.0/gems/puma-6.6.0/lib/puma/request.rb:99
c:0006 p:0015 s:0049 e:000048 METHOD /app/vendor/bundle/ruby/3.4.0/gems/puma-6.6.0/lib/puma/thread_pool.rb:390
c:0005 p:0353 s:0044 e:000043 METHOD /app/vendor/bundle/ruby/3.4.0/gems/puma-6.6.0/lib/puma/request.rb:98
c:0004 p:0093 s:0029 e:000028 METHOD /app/vendor/bundle/ruby/3.4.0/gems/puma-6.6.0/lib/puma/server.rb:472
c:0003 p:0005 s:0018 e:000017 BLOCK /app/vendor/bundle/ruby/3.4.0/gems/puma-6.6.0/lib/puma/server.rb:254
c:0002 p:0071 s:0014 e:000013 BLOCK /app/vendor/bundle/ruby/3.4.0/gems/puma-6.6.0/lib/puma/thread_pool.rb:167 [FINISH]
c:0001 p:---- s:0003 e:000002 DUMMY [FINISH]
-- Ruby level backtrace information ----------------------------------------
/app/vendor/bundle/ruby/3.4.0/gems/puma-6.6.0/lib/puma/thread_pool.rb:167:in 'block in spawn_thread'
/app/vendor/bundle/ruby/3.4.0/gems/puma-6.6.0/lib/puma/server.rb:254:in 'block in run'
/app/vendor/bundle/ruby/3.4.0/gems/puma-6.6.0/lib/puma/server.rb:472:in 'process_client'
/app/vendor/bundle/ruby/3.4.0/gems/puma-6.6.0/lib/puma/request.rb:98:in 'handle_request'
/app/vendor/bundle/ruby/3.4.0/gems/puma-6.6.0/lib/puma/thread_pool.rb:390:in 'with_force_shutdown'
/pre>
Reproduction Steps
Unknown.
Expected Behavior
Not to crash.
Actual Behavior
Crashes silently.
Ruby Version
3.4.1
SDK Version
5.22.4
Integration and Its Version
Rails (8.0.1)
Sentry Config
Sentry.init do |config|
config.dsn = ENV["SENTRY_DSN"]
# get breadcrumbs from logs
config.breadcrumbs_logger = [:active_support_logger, :http_logger]
# enable profiling
# this is relative to traces_sample_rate
config.profiles_sample_rate = 1.0
# Use Vernier for profiling
config.profiler_class = Sentry::Vernier::Profiler
config.traces_sampler = lambda do |sampling_context|
# if this is the continuation of a trace, just use that decision (rate controlled by the caller)
unless sampling_context[:parent_sampled].nil?
next sampling_context[:parent_sampled]
end
0.5
end
end
Thanks for reporting this Adam 🙇🏻 I'll be looking into this today, but since this is coming from Vernier I'm afraid I won't be able to fix it quickly. One thing I need to check is why segfaults are not being reported for you by Sentry.
we are simply a library that runs within ruby, segfaults crash ruby entirely so there is no way we could catch those. That would require an agent living parallel to the ruby process.
