https://blogs.gentoo.org/ago/2020/07/04/gentoo-tinderbox/ Issue: dev-libs/libcdada-0.6.0 fails tests. Discovered on: amd64 (internal ref: ci) Info about the issue: https://wiki.gentoo.org/wiki/Project:Tinderbox/Common_Issues_Helper#CF0015
Created attachment 898342 [details] build.log build log and emerge --info
Created attachment 898343 [details] 1-test-suite.log 1-test-suite.log
Error(s) that match a know pattern in addition to what has been reported in the summary: ../build-aux/test-driver: line 112: 1406 Segmentation fault "$@" >> "$log_file" 2>&1 ../build-aux/test-driver: line 112: 1413 Segmentation fault "$@" >> "$log_file" 2>&1 FAIL: map_gen_test FAIL: map_test
I can reproduce it with GCC 14, however, all tests pass for me with GCC 15.
Some older GCC 15 versions make tests fail as well. I manually bisected through my binary gcc packages: Gentoo 15.0.0_pre20240505 p1 fails Gentoo 15.0.0_pre20240512 p1 fails Gentoo 15.0.0_pre20240519 p1 pass Gentoo 15.0.0_pre20240526 p1 pass Gentoo 15.0.0_pre20240616 p4 pass Gentoo 15.0.0_pre20240721 p6 pass
The tests pass since GCC commit 99b1daae18c0 ("tree-optimization/114589 - remove profile based sink heuristics"). https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=99b1daae18c095d6c94d32efb77442838e11cbfb
(In reply to Petr Vaněk from comment #6) > The tests pass since GCC commit 99b1daae18c0 ("tree-optimization/114589 - > remove profile based sink heuristics"). > > https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff; > h=99b1daae18c095d6c94d32efb77442838e11cbfb OK, so probably a chance thing (becomes latent now). Can you get a verbose backtrace next for the crash, then also check with asan+ubsan and valgrind?
I bisected gcc to the point where it produces segfaulting code, which is since commit 10478270fe0c ("ipa-sra: Treat REFERENCE_TYPES as always dereferencable"). libcdada basically passes (void*)0x123 to the std::map::find method, which segfaults the binary when it is dereferenced. Just out of curiosity, I reduced the code to a minimal reproducer: ```c++ struct _Rb_tree_iterator { _Rb_tree_iterator(int) {} } typedef *_Link_type; _Link_type _M_lower_bound___x; int _M_lower_bound___y; _Rb_tree_iterator _M_lower_bound(int __k) { while (_M_lower_bound___x) if (__k) _M_lower_bound___x = 0; return _M_lower_bound___y; } struct { _Rb_tree_iterator find(int __k) { _Rb_tree_iterator __j = _M_lower_bound(__k); return __j; } } _M_t; _Rb_tree_iterator find(int __x) { return _M_t.find(__x); } int main() { _Rb_tree_iterator main_it = find(*(int *)291); return 3; } ``` The test can be reproduced with following commands: g++-14 -O2 -o map_test map_test.cpp && ./map_test # segfaults g++-15 -O2 -o map_test map_test.cpp && ./map_test # exits with 3 The -O2 is important, both outputs segfault with -O0 or -O1. The difference in the result is because GCC 14 first moves content of 0x123 address to the eax register and then jumps based on earlier comparison 0000000000001040 <main>: 1040: f3 0f 1e fa endbr64 1044: 48 83 3d d4 2f 00 00 cmpq $0x0,0x2fd4(%rip) # 4020 <_M_lower_bound___x> 104b: 00 104c: 8b 04 25 23 01 00 00 mov 0x123,%eax 1053: 74 16 je 106b <main+0x2b> 1055: 85 c0 test %eax,%eax 1057: 75 07 jne 1060 <main+0x20> 1059: eb fe jmp 1059 <main+0x19> 105b: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 1060: 48 c7 05 b5 2f 00 00 movq $0x0,0x2fb5(%rip) # 4020 <_M_lower_bound___x> ... however, GCC 15 produced .text which directly jumps after a comparison and thus it skips the move because the map is empty. 0000000000001040 <main>: 1040: f3 0f 1e fa endbr64 1044: 48 83 3d d4 2f 00 00 cmpq $0x0,0x2fd4(%rip) # 4020 <_M_lower_bound___x> 104b: 00 104c: 74 1d je 106b <main+0x2b> 104e: 8b 04 25 23 01 00 00 mov 0x123,%eax 1055: 85 c0 test %eax,%eax 1057: 75 07 jne 1060 <main+0x20> 1059: eb fe jmp 1059 <main+0x19> 105b: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 1060: 48 c7 05 b5 2f 00 00 movq $0x0,0x2fb5(%rip) # 4020 <_M_lower_bound___x> ...
The bug has been closed via the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=53c5241d0067680af1393881962afaa5a83bfe32 commit 53c5241d0067680af1393881962afaa5a83bfe32 Author: Petr Vaněk <arkamar@gentoo.org> AuthorDate: 2024-07-30 06:03:29 +0000 Commit: Petr Vaněk <arkamar@gentoo.org> CommitDate: 2024-07-30 06:07:11 +0000 dev-libs/libcdada: add 0.6.1 Closes: https://bugs.gentoo.org/936651 Signed-off-by: Petr Vaněk <arkamar@gentoo.org> dev-libs/libcdada/Manifest | 1 + dev-libs/libcdada/libcdada-0.6.1.ebuild | 53 +++++++++++++++++++++++++++++++++ 2 files changed, 54 insertions(+)
