diff --git a/Cabal/src/Distribution/Utils/LogProgress.hs b/Cabal/src/Distribution/Utils/LogProgress.hs
index b8484eecc14..ff90d47983c 100644
--- a/Cabal/src/Distribution/Utils/LogProgress.hs
+++ b/Cabal/src/Distribution/Utils/LogProgress.hs
@@ -16,6 +16,7 @@ import Prelude ()
 import Distribution.Simple.Utils
 import Distribution.Utils.Progress
 import Distribution.Verbosity
+import GHC.Stack (HasCallStack, callStack, prettyCallStack)
 import System.IO (hPutStrLn)
 import Text.PrettyPrint
 
@@ -76,10 +77,14 @@ infoProgress s = LogProgress $ \env ->
     stepProgress s
 
 -- | Fail the computation with an error message.
-dieProgress :: Doc -> LogProgress a
+dieProgress :: HasCallStack => Doc -> LogProgress a
 dieProgress s = LogProgress $ \env ->
   failProgress $
-    hang (text "Error:") 4 (formatMsg (le_context env) s)
+    hang (text "Error:") 4 $
+      vcat
+        [ formatMsg (le_context env) s
+        , vcat (map text (lines (prettyCallStack callStack)))
+        ]
 
 -- | Format a message with context. (Something simple for now.)
 formatMsg :: [CtxMsg] -> Doc -> Doc
diff --git a/cabal-install/src/Distribution/Client/ProjectPlanning.hs b/cabal-install/src/Distribution/Client/ProjectPlanning.hs
index f6d97a8f8fa..3a32814e8b3 100644
--- a/cabal-install/src/Distribution/Client/ProjectPlanning.hs
+++ b/cabal-install/src/Distribution/Client/ProjectPlanning.hs
@@ -232,6 +232,7 @@ import qualified Data.Map as Map
 import qualified Data.Set as Set
 import Distribution.Client.Errors
 import Distribution.Solver.Types.ProjectConfigPath
+import GHC.Stack (HasCallStack)
 import System.Directory (getCurrentDirectory)
 import System.FilePath
 import qualified Text.PrettyPrint as Disp
@@ -352,7 +353,8 @@ sanityCheckElaboratedPackage
 -- | Return the up-to-date project config and information about the local
 -- packages within the project.
 rebuildProjectConfig
-  :: Verbosity
+  :: HasCallStack
+  => Verbosity
   -> HttpTransport
   -> DistDirLayout
   -> ProjectConfig
@@ -633,7 +635,8 @@ See #9840 for more information about the problems surrounding the lossy
 -- dependencies of executables and setup scripts.
 --
 rebuildInstallPlan
-  :: Verbosity
+  :: HasCallStack
+  => Verbosity
   -> DistDirLayout
   -> CabalDirLayout
   -> ProjectConfig
@@ -874,7 +877,8 @@ rebuildInstallPlan
       -- version of the plan has the final nix-style hashed ids.
       --
       phaseElaboratePlan
-        :: ProjectConfig
+        :: HasCallStack
+        => ProjectConfig
         -> (Compiler, Platform, ProgramDb)
         -> Maybe PkgConfigDb
         -> SolverInstallPlan
@@ -1629,7 +1633,8 @@ planPackages
 -- In theory should be able to make an elaborated install plan with a policy
 -- matching that of the classic @cabal install --user@ or @--global@
 elaborateInstallPlan
-  :: Verbosity
+  :: HasCallStack
+  => Verbosity
   -> Platform
   -> Compiler
   -> ProgramDb
@@ -1688,8 +1693,7 @@ elaborateInstallPlan
                   )
           f _ = Nothing
 
-      elaboratedInstallPlan
-        :: LogProgress (InstallPlan.GenericInstallPlan IPI.InstalledPackageInfo ElaboratedConfiguredPackage)
+      elaboratedInstallPlan :: HasCallStack => LogProgress ElaboratedInstallPlan
       elaboratedInstallPlan =
         flip InstallPlan.fromSolverInstallPlanWithProgress solverPlan $ \mapDep planpkg ->
           case planpkg of
diff --git a/cabal-testsuite/PackageTests/Backpack/Fail1/setup.cabal.out b/cabal-testsuite/PackageTests/Backpack/Fail1/setup.cabal.out
index 7c4901d3bea..0c1c239a88c 100644
--- a/cabal-testsuite/PackageTests/Backpack/Fail1/setup.cabal.out
+++ b/cabal-testsuite/PackageTests/Backpack/Fail1/setup.cabal.out
@@ -5,3 +5,5 @@ Error:
         MissingReq
     In mixins: Fail1:sig requires (MissingReq as A)
     In the stanza library
+    CallStack (from HasCallStack):
+      dieProgress, called at src/Distribution/Backpack/LinkedComponent.hs:_:_ in Cabal-3.17.0.0-inplace:Distribution.Backpack.LinkedComponent
diff --git a/cabal-testsuite/PackageTests/Backpack/Fail1/setup.out b/cabal-testsuite/PackageTests/Backpack/Fail1/setup.out
index 7c4901d3bea..e0208376508 100644
--- a/cabal-testsuite/PackageTests/Backpack/Fail1/setup.out
+++ b/cabal-testsuite/PackageTests/Backpack/Fail1/setup.out
@@ -5,3 +5,5 @@ Error:
         MissingReq
     In mixins: Fail1:sig requires (MissingReq as A)
     In the stanza library
+    CallStack (from HasCallStack):
+  dieProgress, called at src/Distribution/Backpack/LinkedComponent.hs:_:_ in Cabal-3.17.0.0-inplace:Distribution.Backpack.LinkedComponent
diff --git a/cabal-testsuite/PackageTests/Backpack/Fail2/setup.cabal.out b/cabal-testsuite/PackageTests/Backpack/Fail2/setup.cabal.out
index e865213bc56..96fc63ec0d4 100644
--- a/cabal-testsuite/PackageTests/Backpack/Fail2/setup.cabal.out
+++ b/cabal-testsuite/PackageTests/Backpack/Fail2/setup.cabal.out
@@ -3,3 +3,5 @@ Configuring Fail2-0.1.0.0...
 Error:
     Mix-in refers to non-existent library 'non-existent'
     (did you forget to add the package to build-depends?)
+    CallStack (from HasCallStack):
+      dieProgress, called at src/Distribution/Backpack/ConfiguredComponent.hs:_:_ in Cabal-3.17.0.0-inplace:Distribution.Backpack.ConfiguredComponent
diff --git a/cabal-testsuite/PackageTests/Backpack/Fail2/setup.out b/cabal-testsuite/PackageTests/Backpack/Fail2/setup.out
index e865213bc56..b2d0eb2dd97 100644
--- a/cabal-testsuite/PackageTests/Backpack/Fail2/setup.out
+++ b/cabal-testsuite/PackageTests/Backpack/Fail2/setup.out
@@ -3,3 +3,5 @@ Configuring Fail2-0.1.0.0...
 Error:
     Mix-in refers to non-existent library 'non-existent'
     (did you forget to add the package to build-depends?)
+    CallStack (from HasCallStack):
+  dieProgress, called at src/Distribution/Backpack/ConfiguredComponent.hs:_:_ in Cabal-3.17.0.0-inplace:Distribution.Backpack.ConfiguredComponent
diff --git a/cabal-testsuite/PackageTests/Backpack/Fail3/setup.cabal.out b/cabal-testsuite/PackageTests/Backpack/Fail3/setup.cabal.out
index cdf8656f78f..0f222d9dbd9 100644
--- a/cabal-testsuite/PackageTests/Backpack/Fail3/setup.cabal.out
+++ b/cabal-testsuite/PackageTests/Backpack/Fail3/setup.cabal.out
@@ -4,3 +4,5 @@ Error:
     Non-library component has unfilled requirements:
         UnfilledSig brought into scope by build-depends: Fail1
     In the stanza executable foo
+    CallStack (from HasCallStack):
+      dieProgress, called at src/Distribution/Backpack/LinkedComponent.hs:_:_ in Cabal-3.17.0.0-inplace:Distribution.Backpack.LinkedComponent
diff --git a/cabal-testsuite/PackageTests/Backpack/Fail3/setup.out b/cabal-testsuite/PackageTests/Backpack/Fail3/setup.out
index cdf8656f78f..61f9d54b319 100644
--- a/cabal-testsuite/PackageTests/Backpack/Fail3/setup.out
+++ b/cabal-testsuite/PackageTests/Backpack/Fail3/setup.out
@@ -4,3 +4,5 @@ Error:
     Non-library component has unfilled requirements:
         UnfilledSig brought into scope by build-depends: Fail1
     In the stanza executable foo
+    CallStack (from HasCallStack):
+  dieProgress, called at src/Distribution/Backpack/LinkedComponent.hs:_:_ in Cabal-3.17.0.0-inplace:Distribution.Backpack.LinkedComponent
diff --git a/cabal-testsuite/PackageTests/Backpack/Includes2/setup-internal-fail.cabal.out b/cabal-testsuite/PackageTests/Backpack/Includes2/setup-internal-fail.cabal.out
index e16f8623d52..fe2575ed881 100644
--- a/cabal-testsuite/PackageTests/Backpack/Includes2/setup-internal-fail.cabal.out
+++ b/cabal-testsuite/PackageTests/Backpack/Includes2/setup-internal-fail.cabal.out
@@ -13,3 +13,5 @@ Error:
                            brought into scope by mixins: fail:postgresql (Database.PostgreSQL as Database)
       While filling requirements of build-depends: fail:mylib
     In the stanza library
+    CallStack (from HasCallStack):
+      dieProgress, called at src/Distribution/Backpack/LinkedComponent.hs:_:_ in Cabal-3.17.0.0-inplace:Distribution.Backpack.LinkedComponent
diff --git a/cabal-testsuite/PackageTests/Backpack/Includes2/setup-internal-fail.out b/cabal-testsuite/PackageTests/Backpack/Includes2/setup-internal-fail.out
index e16f8623d52..c543464a616 100644
--- a/cabal-testsuite/PackageTests/Backpack/Includes2/setup-internal-fail.out
+++ b/cabal-testsuite/PackageTests/Backpack/Includes2/setup-internal-fail.out
@@ -13,3 +13,5 @@ Error:
                            brought into scope by mixins: fail:postgresql (Database.PostgreSQL as Database)
       While filling requirements of build-depends: fail:mylib
     In the stanza library
+    CallStack (from HasCallStack):
+  dieProgress, called at src/Distribution/Backpack/LinkedComponent.hs:_:_ in Cabal-3.17.0.0-inplace:Distribution.Backpack.LinkedComponent
diff --git a/cabal-testsuite/PackageTests/Backpack/Reexport2/cabal.out b/cabal-testsuite/PackageTests/Backpack/Reexport2/cabal.out
index 31c9428dcaf..feda7699ab6 100644
--- a/cabal-testsuite/PackageTests/Backpack/Reexport2/cabal.out
+++ b/cabal-testsuite/PackageTests/Backpack/Reexport2/cabal.out
@@ -8,3 +8,5 @@ Error:
         nor any of its 'build-depends' dependencies.
     In the stanza 'library'
     In the inplace package 'Reexport2-1.0'
+    CallStack (from HasCallStack):
+      dieProgress, called at src/Distribution/Backpack/LinkedComponent.hs:_:_ in Cabal-3.17.0.0-inplace:Distribution.Backpack.LinkedComponent
diff --git a/cabal-testsuite/PackageTests/Backpack/T4447/setup.cabal.out b/cabal-testsuite/PackageTests/Backpack/T4447/setup.cabal.out
index ff9ad4456e6..3590040a9f0 100644
--- a/cabal-testsuite/PackageTests/Backpack/T4447/setup.cabal.out
+++ b/cabal-testsuite/PackageTests/Backpack/T4447/setup.cabal.out
@@ -7,3 +7,5 @@ Error:
     Try moving this module to a separate library, e.g.,
     create a new stanza: library 'sublib'.
     In the stanza executable foo-exe
+    CallStack (from HasCallStack):
+      dieProgress, called at src/Distribution/Backpack/LinkedComponent.hs:_:_ in Cabal-3.17.0.0-inplace:Distribution.Backpack.LinkedComponent
diff --git a/cabal-testsuite/PackageTests/Backpack/T4447/setup.out b/cabal-testsuite/PackageTests/Backpack/T4447/setup.out
index ff9ad4456e6..c12fc288a8a 100644
--- a/cabal-testsuite/PackageTests/Backpack/T4447/setup.out
+++ b/cabal-testsuite/PackageTests/Backpack/T4447/setup.out
@@ -7,3 +7,5 @@ Error:
     Try moving this module to a separate library, e.g.,
     create a new stanza: library 'sublib'.
     In the stanza executable foo-exe
+    CallStack (from HasCallStack):
+  dieProgress, called at src/Distribution/Backpack/LinkedComponent.hs:_:_ in Cabal-3.17.0.0-inplace:Distribution.Backpack.LinkedComponent
diff --git a/cabal-testsuite/PackageTests/Backpack/T8582/setup.cabal.out b/cabal-testsuite/PackageTests/Backpack/T8582/setup.cabal.out
index 577cf201e39..2501933c6af 100644
--- a/cabal-testsuite/PackageTests/Backpack/T8582/setup.cabal.out
+++ b/cabal-testsuite/PackageTests/Backpack/T8582/setup.cabal.out
@@ -4,4 +4,6 @@ Error:
     Cannot instantiate requirement 'ImplA'
     Ensure "build-depends:" doesn't include any library with signatures: 'A'
     as this creates a cyclic dependency, which GHC does not support.
-    In the stanza executable exe
\ No newline at end of file
+    In the stanza executable exe
+    CallStack (from HasCallStack):
+      dieProgress, called at src/Distribution/Backpack/LinkedComponent.hs:_:_ in Cabal-3.17.0.0-inplace:Distribution.Backpack.LinkedComponent
diff --git a/cabal-testsuite/PackageTests/Backpack/T8582/setup.out b/cabal-testsuite/PackageTests/Backpack/T8582/setup.out
index 577cf201e39..982671d3f36 100644
--- a/cabal-testsuite/PackageTests/Backpack/T8582/setup.out
+++ b/cabal-testsuite/PackageTests/Backpack/T8582/setup.out
@@ -4,4 +4,6 @@ Error:
     Cannot instantiate requirement 'ImplA'
     Ensure "build-depends:" doesn't include any library with signatures: 'A'
     as this creates a cyclic dependency, which GHC does not support.
-    In the stanza executable exe
\ No newline at end of file
+    In the stanza executable exe
+    CallStack (from HasCallStack):
+  dieProgress, called at src/Distribution/Backpack/LinkedComponent.hs:_:_ in Cabal-3.17.0.0-inplace:Distribution.Backpack.LinkedComponent
diff --git a/cabal-testsuite/PackageTests/BuildDeps/DepCycle/cabal.out b/cabal-testsuite/PackageTests/BuildDeps/DepCycle/cabal.out
index 966c934480b..44625541255 100644
--- a/cabal-testsuite/PackageTests/BuildDeps/DepCycle/cabal.out
+++ b/cabal-testsuite/PackageTests/BuildDeps/DepCycle/cabal.out
@@ -5,3 +5,8 @@ Error:
         library bar
         library foo
     In the inplace package 'DepCycle-1.0'
+    CallStack (from HasCallStack):
+      dieProgress, called at src/Distribution/Client/ProjectPlanning.hs:_:_ in cabal-install-3.17.0.0-inplace:Distribution.Client.ProjectPlanning
+      elaborateInstallPlan, called at src/Distribution/Client/ProjectPlanning.hs:_:_ in cabal-install-3.17.0.0-inplace:Distribution.Client.ProjectPlanning
+      phaseElaboratePlan, called at src/Distribution/Client/ProjectPlanning.hs:_:_ in cabal-install-3.17.0.0-inplace:Distribution.Client.ProjectPlanning
+      rebuildInstallPlan, called at src/Distribution/Client/ProjectOrchestration.hs:_:_ in cabal-install-3.17.0.0-inplace:Distribution.Client.ProjectOrchestration
diff --git a/cabal-testsuite/PackageTests/BuildDeps/DepCycle/setup.cabal.out b/cabal-testsuite/PackageTests/BuildDeps/DepCycle/setup.cabal.out
index 16840243da9..114a7e6fe77 100644
--- a/cabal-testsuite/PackageTests/BuildDeps/DepCycle/setup.cabal.out
+++ b/cabal-testsuite/PackageTests/BuildDeps/DepCycle/setup.cabal.out
@@ -3,3 +3,5 @@ Configuring DepCycle-1.0...
 Error:
     Components in the package DepCycle-1.0 depend on each other in a cyclic way:
     'library 'bar'' depends on 'library 'foo'' depends on 'library 'bar''
+    CallStack (from HasCallStack):
+      dieProgress, called at src/Distribution/Backpack/Configure.hs:_:_ in Cabal-3.17.0.0-inplace:Distribution.Backpack.Configure
diff --git a/cabal-testsuite/PackageTests/BuildDeps/DepCycle/setup.out b/cabal-testsuite/PackageTests/BuildDeps/DepCycle/setup.out
index 16840243da9..114a7e6fe77 100644
--- a/cabal-testsuite/PackageTests/BuildDeps/DepCycle/setup.out
+++ b/cabal-testsuite/PackageTests/BuildDeps/DepCycle/setup.out
@@ -3,3 +3,5 @@ Configuring DepCycle-1.0...
 Error:
     Components in the package DepCycle-1.0 depend on each other in a cyclic way:
     'library 'bar'' depends on 'library 'foo'' depends on 'library 'bar''
+    CallStack (from HasCallStack):
+      dieProgress, called at src/Distribution/Backpack/Configure.hs:_:_ in Cabal-3.17.0.0-inplace:Distribution.Backpack.Configure
diff --git a/cabal-testsuite/PackageTests/InternalLibraries/cabal-per-package.out b/cabal-testsuite/PackageTests/InternalLibraries/cabal-per-package.out
index 72a24d04059..0fa07259c25 100644
--- a/cabal-testsuite/PackageTests/InternalLibraries/cabal-per-package.out
+++ b/cabal-testsuite/PackageTests/InternalLibraries/cabal-per-package.out
@@ -4,3 +4,8 @@ Error:
     Internal libraries only supported with per-component builds.
     Per-component builds were disabled because you passed --disable-per-component
     In the inplace package 'p-0.1.0.0'
+    CallStack (from HasCallStack):
+      dieProgress, called at src/Distribution/Client/ProjectPlanning.hs:_:_ in cabal-install-3.17.0.0-inplace:Distribution.Client.ProjectPlanning
+      elaborateInstallPlan, called at src/Distribution/Client/ProjectPlanning.hs:_:_ in cabal-install-3.17.0.0-inplace:Distribution.Client.ProjectPlanning
+      phaseElaboratePlan, called at src/Distribution/Client/ProjectPlanning.hs:_:_ in cabal-install-3.17.0.0-inplace:Distribution.Client.ProjectPlanning
+      rebuildInstallPlan, called at src/Distribution/Client/ProjectOrchestration.hs:_:_ in cabal-install-3.17.0.0-inplace:Distribution.Client.ProjectOrchestration
diff --git a/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-ambiguous.cabal.out b/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-ambiguous.cabal.out
index a2ed311a502..a09d0b78b26 100644
--- a/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-ambiguous.cabal.out
+++ b/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-ambiguous.cabal.out
@@ -21,3 +21,5 @@ Error:
         re-export with a package name.
         The syntax is 'packagename:ModuleName [as NewName]'.
     In the stanza library
+    CallStack (from HasCallStack):
+      dieProgress, called at src/Distribution/Backpack/LinkedComponent.hs:_:_ in Cabal-3.17.0.0-inplace:Distribution.Backpack.LinkedComponent
diff --git a/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-ambiguous.out b/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-ambiguous.out
index a2ed311a502..d8d4f3522be 100644
--- a/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-ambiguous.out
+++ b/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-ambiguous.out
@@ -21,3 +21,5 @@ Error:
         re-export with a package name.
         The syntax is 'packagename:ModuleName [as NewName]'.
     In the stanza library
+    CallStack (from HasCallStack):
+  dieProgress, called at src/Distribution/Backpack/LinkedComponent.hs:_:_ in Cabal-3.17.0.0-inplace:Distribution.Backpack.LinkedComponent
diff --git a/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-missing.cabal.out b/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-missing.cabal.out
index 9283ea2ea31..cf9670d7dd7 100644
--- a/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-missing.cabal.out
+++ b/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-missing.cabal.out
@@ -7,3 +7,5 @@ Error:
         It occurs in neither the 'exposed-modules' of this package,
         nor any of its 'build-depends' dependencies.
     In the stanza library
+    CallStack (from HasCallStack):
+      dieProgress, called at src/Distribution/Backpack/LinkedComponent.hs:_:_ in Cabal-3.17.0.0-inplace:Distribution.Backpack.LinkedComponent
diff --git a/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-missing.out b/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-missing.out
index 9283ea2ea31..081035a8796 100644
--- a/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-missing.out
+++ b/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-missing.out
@@ -7,3 +7,5 @@ Error:
         It occurs in neither the 'exposed-modules' of this package,
         nor any of its 'build-depends' dependencies.
     In the stanza library
+    CallStack (from HasCallStack):
+  dieProgress, called at src/Distribution/Backpack/LinkedComponent.hs:_:_ in Cabal-3.17.0.0-inplace:Distribution.Backpack.LinkedComponent
diff --git a/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-other.cabal.out b/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-other.cabal.out
index 4f5433c09d6..0bcddb2cfba 100644
--- a/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-other.cabal.out
+++ b/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-other.cabal.out
@@ -7,3 +7,5 @@ Error:
         It occurs in neither the 'exposed-modules' of this package,
         nor any of its 'build-depends' dependencies.
     In the stanza library
+    CallStack (from HasCallStack):
+      dieProgress, called at src/Distribution/Backpack/LinkedComponent.hs:_:_ in Cabal-3.17.0.0-inplace:Distribution.Backpack.LinkedComponent
diff --git a/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-other.out b/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-other.out
index 4f5433c09d6..36bab27bb83 100644
--- a/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-other.out
+++ b/cabal-testsuite/PackageTests/ReexportedModules/setup-fail-other.out
@@ -7,3 +7,5 @@ Error:
         It occurs in neither the 'exposed-modules' of this package,
         nor any of its 'build-depends' dependencies.
     In the stanza library
+    CallStack (from HasCallStack):
+  dieProgress, called at src/Distribution/Backpack/LinkedComponent.hs:_:_ in Cabal-3.17.0.0-inplace:Distribution.Backpack.LinkedComponent
diff --git a/cabal-testsuite/src/Test/Cabal/OutputNormalizer.hs b/cabal-testsuite/src/Test/Cabal/OutputNormalizer.hs
index c4b45c6f161..f7bdc796ce4 100644
--- a/cabal-testsuite/src/Test/Cabal/OutputNormalizer.hs
+++ b/cabal-testsuite/src/Test/Cabal/OutputNormalizer.hs
@@ -95,6 +95,7 @@ normalizeOutput nenv =
     -- hackage-security locks occur non-deterministically
     . resub "(Released|Acquired|Waiting) .*hackage-security-lock\n" ""
     . resub "installed: [0-9]+(\\.[0-9]+)*" "installed: <VERSION>"
+    . resub "\\.hs:[0-9]+:[0-9]+" ".hs:_:_"
   where
     sameDir = "(\\.((\\\\)+|\\/))*"
     packageIdRegex pid =