[GHC] #13501: TH segmentation fault on Linux when calling function from another package
#13501: TH segmentation fault on Linux when calling function from another package -------------------------------------+------------------------------------- Reporter: jmaki | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Keywords: | Operating System: Linux Architecture: x86_64 | Type of failure: Compile-time (amd64) | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The bug was hit when using Buck (buckbuild.com) to build. I had two packages, A containing a single module with a TH function of type `TH.Q [TH.Dec]` and module B importing A it and calling that function at top-level. I've attached a tarball that reproduces the problem. I've verified that the problem occurs with 7.10.3, 8.0.2 and a semi-recent GHC HEAD from @bitonic. The issue doesn't occur on macOS and does not occur when the modules are in a single package or if the package is compiled as a shared library. The problem also does not occur when using stack, so this is likely related to how buck creates packages. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13501 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13501: TH segmentation fault on Linux when calling function from another package -------------------------------------+------------------------------------- Reporter: jmaki | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by jmaki): * Attachment "repro.tar.gz" added. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13501 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13501: TH segmentation fault on Linux when calling function from another package -------------------------------------+------------------------------------- Reporter: jmaki | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Description changed by jmaki: Old description:
The bug was hit when using Buck (buckbuild.com) to build. I had two packages, A containing a single module with a TH function of type `TH.Q [TH.Dec]` and module B importing A it and calling that function at top-level. I've attached a tarball that reproduces the problem.
I've verified that the problem occurs with 7.10.3, 8.0.2 and a semi- recent GHC HEAD from @bitonic. The issue doesn't occur on macOS and does not occur when the modules are in a single package or if the package is compiled as a shared library. The problem also does not occur when using stack, so this is likely related to how buck creates packages.
New description: The bug was hit when using Buck (buckbuild.com) to build. I had two packages, A containing a single module with a TH function of type `TH.Q [TH.Dec]` and module B importing A it and calling that function at top-level. I've attached a tarball that reproduces the problem using just 'ghc', 'ghc-pkg' and 'ar'. I've verified that the problem occurs with 7.10.3, 8.0.2 and a semi-recent GHC HEAD from @bitonic. The issue doesn't occur on macOS and does not occur when the modules are in a single package or if the package is compiled as a shared library. The problem also does not occur when using stack, so this is likely related to how buck creates packages. -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13501#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13501: TH segmentation fault on Linux when calling function from another package -------------------------------------+------------------------------------- Reporter: jmaki | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by bgamari): Thanks for the repro! There is definitely something fishy here. GDB says, {{{ Thread 1 received signal SIGSEGV, Segmentation fault. 0x00007f631235ed30 in base_GHCziBase_return_info () from /opt/exp/ghc/roots/master/lib/ghc-8.3.20170329/bin/../base-4.10.0.0/libHSbase-4.10.0.0-ghc8.3.20170329.so (rr) bt #0 0x00007f631235ed30 in base_GHCziBase_return_info () from /opt/exp/ghc/roots/master/lib/ghc-8.3.20170329/bin/../base-4.10.0.0/libHSbase-4.10.0.0-ghc8.3.20170329.so #1 0x0000000000000000 in ?? () (rr) }}} passing `+RTS -Dl` we get the following forboding warnings, {{{ ... Rel entry 4 is raw( 0x54 0x160000000b (nil)) lookupSymbol: looking up stg_ap_p_info lookupSymbol: value of stg_ap_p_info is 0x7f63112740c8 `stg_ap_p_info' resolves to 0x7f63112740c8 Reloc: P = 0x401311ec S = 0x7f63112740c8 A = (nil) Rel entry 5 is raw( 0x5c 0x170000000b 0x1) lookupSymbol: looking up ghczmprim_GHCziTypes_ZMZN_closure lookupSymbol: symbol not found `ghczmprim_GHCziTypes_ZMZN_closure' resolves to 0x7f6311b41d50 Reloc: P = 0x401311f4 S = 0x7f6311b41d50 A = 0x1 Rel entry 6 is raw( 0x65 0x1800000002 0xfffffffffffffffc) lookupSymbol: looking up base_GHCziBase_return_info lookupSymbol: symbol not found `base_GHCziBase_return_info' resolves to 0x7f631235ed10 Reloc: P = 0x401311fd S = 0x7f631235ed10 A = 0xfffffffffffffffc relocations for section 3 using symtab 11 Rel entry 0 is raw( (nil) 0xe00000001 (nil)) lookupSymbol: looking up ghczmprim_GHCziTypes_TrNameS_con_info lookupSymbol: symbol not found `ghczmprim_GHCziTypes_TrNameS_con_info' resolves to 0x7f63118655c0 Reloc: P = 0x40131208 S = 0x7f63118655c0 A = (nil) ... }}} Looking at the `libHSbase` archive, we see, {{{ $ objdump -x /opt/exp/ghc/roots/master/lib/ghc-8.3.20170329/base-4.10.0.0/libHSbase-4.10.0.0.a | less ... SYMBOL TABLE: ... 0000000000000000 *UND* 0000000000000000 base_GHCziBase_return_info }}} Very interesting. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13501#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13501: TH segmentation fault on Linux when calling function from another package -------------------------------------+------------------------------------- Reporter: jmaki | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by bgamari): In contrast, the monolithic object file contains the symbol, {{{ $ objdump -x /opt/exp/ghc/roots/master/lib/ghc-8.3.20170329/base-4.10.0.0/HSbase-4.10.0.0.o | less ... SYMBOL TABLE: ... 00000000001b1150 g O .text 0000000000000045 base_GHCziBase_return_info }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13501#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13501: TH segmentation fault on Linux when calling function from another package -------------------------------------+------------------------------------- Reporter: jmaki | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by bgamari): Hmmm, looking back at `GHC/Base.o`, {{{ $ objdump -x /opt/exp/ghc/ghc-master/libraries/base/dist- install/build/GHC/Base.o | less ... SYMBOL TABLE: ... 0000000000000050 l .text.base_GHCziBase_zgzg_info 0000000000000000 c5Mf_info 0000000000000000 l d .data.base_GHCziBase_return_closure 0000000000000000 .data.base_GHCziBase_return_closure 0000000000000000 l d .text.base_GHCziBase_return_info 0000000000000000 .text.base_GHCziBase_return_info 0000000000000050 l .text.base_GHCziBase_return_info 0000000000000000 c5Mx_info 0000000000000000 l d .data.base_GHCziBase_fail_closure 0000000000000000 .data.base_GHCziBase_fail_closure 0000000000000000 l d .text.base_GHCziBase_fail_info 0000000000000000 .text.base_GHCziBase_fail_info ... 0000000000000018 g O .text.base_GHCziBase_zgzg_info 0000000000000045 base_GHCziBase_zgzg_info 0000000000000000 g O .data.base_GHCziBase_return_closure 0000000000000000 base_GHCziBase_return_closure 0000000000000018 g O .text.base_GHCziBase_return_info 0000000000000045 base_GHCziBase_return_info 0000000000000000 g O .data.base_GHCziBase_fail_closure 0000000000000000 base_GHCziBase_fail_closure }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13501#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13501: TH segmentation fault on Linux when calling function from another package -------------------------------------+------------------------------------- Reporter: jmaki | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by bgamari): One interesting observation is that there are two modules named `Base.o` that get placed in the archive file, {{{ $ ar t dist-install/build/libHSbase-4.10.0.0.a | grep Base Base.o Base.o }}} One of these is `GHC.Base` and the other is `Control.Exception.Base`. Given that `ar --print-armap` reports `base_GHCziBase_return_info` as defined I wonder whether the RTS linker fails to find the symbol due to this repeated object name. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13501#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13501: TH segmentation fault on Linux when calling function from another package -------------------------------------+------------------------------------- Reporter: jmaki | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by bgamari): Regarding comment:5: I suspect not given that this is a dynamic GHC; in fact, I believe GHC shouldn't actually load **any** objects for `base` since it is one of the packages in `Linker.partOfGHCi`. I have confirmed that the symbol is present in the `libHSbase` shared object. Nevertheless, it might be good to circle back and look into the archive oddness seen in comment:2 after nailing this bug. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13501#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13501: TH segmentation fault on Linux when calling function from another package -------------------------------------+------------------------------------- Reporter: jmaki | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by bgamari): So the symbols in question are indeed being resolved by the dynamic linker (using the "main program" handle). -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13501#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13501: TH segmentation fault on Linux when calling function from another package -------------------------------------+------------------------------------- Reporter: jmaki | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by jmaki): Switching to link-style 'static_pic' in buck fixes the issue. Difference to "repro": {{{ -ghc -no-link -package-name foo -i Foo.hs -Wall -Werror +ghc -fPIC -dynamic -hisuf dyn_hi -no-link -package-name foo -i Foo.hs -Wall -Werror -ghc -no-link -package-name bar -package-db ../foo/pkg -package foo \ +ghc -fPIC -dynamic -no-link -package-name bar -package-db ../foo/pkg -package foo-1.0.0 \ Bar.hs }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13501#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13501: TH segmentation fault on Linux when calling function from another package -------------------------------------+------------------------------------- Reporter: jmaki | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Resolution: | Keywords: | DynamicLinking Operating System: Linux | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * keywords: => DynamicLinking Comment: Well, that essentially confirms that the issue is related to dynamic linking. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13501#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
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