Re: Still seeing Failed assertion: "p[i] == 0" on armv7 buildworld [gdb backtrace! End of area has 0x5a5a5a5a sequence]

On Nov 18, 2025, at 10:18, Mark Millard <[email protected]> wrote:

> I modified system clang to not register its 2 SIGABRT handlers.
> 
> The backtrace has the jemalloc call stack activity as well.
> 
> (gdb) bt
> #0  thr_kill () at thr_kill.S:4
> #1  0x2a08ef24 in __raise (s=6) at /usr/src/lib/libc/gen/raise.c:48
> #2  0x2a145f38 in abort () at /usr/src/lib/libc/stdlib/abort.c:61
> #3  0x2a196128 in ehooks_debug_zero_check (addr=addr@entry=0x2b629000, size=size@entry=12288) at /usr/src/contrib/jemalloc/include/jemalloc/internal/ehooks.h:170
> #4  0x2a191f60 in ehooks_alloc (tsdn=0x2a2e4060, ehooks=0x2a600080, new_addr=0x0, size=<optimized out>, alignment=4096, zero=0xffff6f17, commit=<optimized out>)
>    at /usr/src/contrib/jemalloc/include/jemalloc/internal/ehooks.h:208
> #5  __je_extent_alloc_wrapper (tsdn=tsdn@entry=0x2a2e4060, pac=0x2a601810, ehooks=<optimized out>, new_addr=<optimized out>, size=12288, alignment=4096, zero=true, commit=0xffff6f77, 
>    growing_retained=<optimized out>) at jemalloc_extent.c:1003
> #6  0x2a1916e0 in __je_ecache_alloc_grow (tsdn=<optimized out>, tsdn@entry=0x2a2e4060, pac=pac@entry=0x2a601810, ehooks=ehooks@entry=0x2a600080, ecache=<optimized out>, ecache@entry=0x2a603dd0, 
>    expand_edata=0x0, size=12288, alignment=4096, zero=<optimized out>, guarded=<optimized out>) at jemalloc_extent.c:126
> #7  0x2a1c9680 in pac_alloc_real (tsdn=0x2a2e4060, pac=0x2a601810, ehooks=0x2a600080, size=12288, alignment=4096, zero=<optimized out>, guarded=false) at jemalloc_pac.c:124
> #8  pac_alloc_impl (tsdn=tsdn@entry=0x2a2e4060, self=0x2a601810, size=size@entry=12288, alignment=4096, zero=<optimized out>, guarded=false, frequent_reuse=<optimized out>, 
>    deferred_work_generated=<optimized out>) at jemalloc_pac.c:178
> #9  0x2a1c7ae8 in pai_alloc (tsdn=0x2a2e4060, self=0x0, size=12288, alignment=2147483615, zero=<optimized out>, guarded=false, frequent_reuse=true, deferred_work_generated=<optimized out>)
>    at /usr/src/contrib/jemalloc/include/jemalloc/internal/pai.h:43
> #10 __je_pa_alloc (tsdn=tsdn@entry=0x2a2e4060, shard=shard@entry=0x2a601800, size=12288, alignment=<optimized out>, slab=true, szind=25, zero=<optimized out>, guarded=false, 
>    deferred_work_generated=0xffff703f) at jemalloc_pa.c:139
> #11 0x2a16b9f8 in arena_slab_alloc (tsdn=tsdn@entry=0x2a2e4060, arena=0x2a600540, binind=25, binshard=0, bin_info=0x2a21ff0c <__je_bin_infos+1200>) at jemalloc_arena.c:839
> #12 0x2a16ac98 in __je_arena_cache_bin_fill_small (tsdn=0x2a2e4060, arena=0x2a600540, cache_bin=cache_bin@entry=0x2a2e4528, cache_bin_info=0x2a6004f2, binind=25, nfill=5) at jemalloc_arena.c:1034
> #13 0x2a1b5694 in __je_tcache_alloc_small_hard (tsdn=0x0, tsdn@entry=0x2a2e4060, arena=0x0, arena@entry=0x2a600540, tcache=tcache@entry=0x2a2e42c8, cache_bin=cache_bin@entry=0x2a2e4528, binind=25, 
>    tcache_success=0xffff70ef) at jemalloc_tcache.c:238
> #14 0x2a16cef4 in tcache_alloc_small (tsd=<optimized out>, arena=0x2a600540, tcache=0x2a2e42c8, size=<optimized out>, binind=25, zero=false, slow_path=true)
>    at /usr/src/contrib/jemalloc/include/jemalloc/internal/tcache_inlines.h:68
> #15 arena_malloc (tsdn=<optimized out>, arena=<optimized out>, size=1536, ind=25, zero=false, tcache=0x2a2e42c8, slow_path=true)
>    at /usr/src/contrib/jemalloc/include/jemalloc/internal/arena_inlines_b.h:151
> #16 0x2a16cb88 in __je_arena_palloc (tsdn=0x0, tsdn@entry=0x2a2e4060, arena=<optimized out>, usize=<optimized out>, usize@entry=1536, alignment=alignment@entry=8, zero=false, tcache=0x2a2e42c8)
>    at jemalloc_arena.c:1224
> #17 0x2a16559c in ipallocztm (tsdn=0x2a2e4060, tsdn@entry=0x2a2e42c8, usize=1536, alignment=8, zero=false, tcache=0x2a2e42c8, is_internal=false, arena=0x0)
>    at /usr/src/contrib/jemalloc/include/jemalloc/internal/jemalloc_internal_inlines_c.h:80
> #18 ipalloct (tsdn=0x0, tsdn@entry=0x2a2e4060, usize=1536, alignment=8, zero=false, tcache=0x2a2e42c8, arena=0x0)
>    at /usr/src/contrib/jemalloc/include/jemalloc/internal/jemalloc_internal_inlines_c.h:91
> #19 0x2a1651f4 in imalloc_no_sample (sopts=0xffff71e4, dopts=0xffff71c4, tsd=0x2a2e4060, size=1536, usize=1536, ind=<optimized out>) at jemalloc_jemalloc.c:2398
> #20 imalloc_body (sopts=0xffff71e4, dopts=0xffff71c4, tsd=0x2a2e4060) at jemalloc_jemalloc.c:2577
> #21 0x2a156188 in imalloc (sopts=sopts@entry=0xffff71e4, dopts=<optimized out>, dopts@entry=0xffff71c4) at jemalloc_jemalloc.c:2693
> #22 0x2a15677c in __aligned_alloc (alignment=8, size=1536) at jemalloc_jemalloc.c:2821
> #23 0x29e61a00 in std::__1::__libcpp_aligned_alloc[abi:se190107](unsigned int, unsigned int) (__alignment=8, __size=<optimized out>)
>    at /usr/src/contrib/llvm-project/libcxx/include/__memory/aligned_alloc.h:43
> #24 operator_new_aligned_impl (size=<optimized out>, alignment=8) at /usr/src/contrib/llvm-project/libcxx/src/new.cpp:129
> #25 operator new (size=<optimized out>, alignment=<optimized out>) at /usr/src/contrib/llvm-project/libcxx/src/new.cpp:141
> #26 0x2631dde0 in allocateBuckets () at /usr/src/contrib/llvm-project/llvm/include/llvm/ADT/DenseMap.h:915
> #27 grow () at /usr/src/contrib/llvm-project/llvm/include/llvm/ADT/DenseMap.h:849
> #28 0x2631dd0c in grow () at /usr/src/contrib/llvm-project/llvm/include/llvm/ADT/DenseMap.h:580
> #29 0x2631dd0c in InsertIntoBucketImpl<llvm::BasicBlock const*> () from /usr/lib/libprivatellvm.so.19
> #30 0x2631daa4 in InsertIntoBucket<llvm::BasicBlock const* const&> () at /usr/src/contrib/llvm-project/llvm/include/llvm/ADT/DenseMap.h:590
> #31 FindAndConstruct () at /usr/src/contrib/llvm-project/llvm/include/llvm/ADT/DenseMap.h:369
> #32 0x2631d49c in operator[] () at /usr/src/contrib/llvm-project/llvm/include/llvm/ADT/DenseMap.h:373
> #33 analyzeBasicBlock () at /usr/src/contrib/llvm-project/llvm/lib/Analysis/CodeMetrics.cpp:234
> #34 0x28e2c3ec in run () at /usr/src/contrib/llvm-project/llvm/lib/Transforms/IPO/FunctionSpecialization.cpp:643
> #35 0x28f4fd70 in runIPSCCP () at /usr/src/contrib/llvm-project/llvm/lib/Transforms/IPO/SCCP.cpp:165
> #36 run () at /usr/src/contrib/llvm-project/llvm/lib/Transforms/IPO/SCCP.cpp:403
> #37 0x27b85d14 in llvm::detail::PassModel<llvm::Module, llvm::IPSCCPPass, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) ()
>    at /usr/src/contrib/llvm-project/llvm/include/llvm/IR/PassManagerInternal.h:90
> #38 0x276ee244 in run () at /usr/src/contrib/llvm-project/llvm/include/llvm/IR/PassManagerImpl.h:81
> #39 0x22174ffc in RunOptimizationPipeline () at /usr/src/contrib/llvm-project/clang/lib/CodeGen/BackendUtil.cpp:1114
> #40 0x2216cfb8 in EmitAssembly () at /usr/src/contrib/llvm-project/clang/lib/CodeGen/BackendUtil.cpp:1179
> #41 EmitBackendOutput () at /usr/src/contrib/llvm-project/clang/lib/CodeGen/BackendUtil.cpp:1341
> #42 0x225cbca0 in HandleTranslationUnit () at /usr/src/contrib/llvm-project/clang/lib/CodeGen/CodeGenAction.cpp:354
> #43 0x22cff8e4 in ParseAST () at /usr/src/contrib/llvm-project/clang/lib/Parse/ParseAST.cpp:184
> #44 0x22b5a7b8 in Execute () at /usr/src/contrib/llvm-project/clang/lib/Frontend/FrontendAction.cpp:1078
> --Type <RET> for more, q to quit, c to continue without paging--
> #45 0x22adb800 in ExecuteAction () at /usr/src/contrib/llvm-project/clang/lib/Frontend/CompilerInstance.cpp:1061
> #46 0x22bf6a90 in ExecuteCompilerInvocation () at /usr/src/contrib/llvm-project/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:280
> #47 0x0002afc8 in cc1_main () at /usr/src/contrib/llvm-project/clang/tools/driver/cc1_main.cpp:284
> #48 0x00038548 in ExecuteCC1Tool () at /usr/src/contrib/llvm-project/clang/tools/driver/driver.cpp:215
> #49 0x227877ec in operator() () at /usr/src/contrib/llvm-project/llvm/include/llvm/ADT/STLFunctionalExtras.h:68
> #50 operator() () at /usr/src/contrib/llvm-project/clang/lib/Driver/Job.cpp:440
> #51 callback_fn<(lambda at /usr/src/contrib/llvm-project/clang/lib/Driver/Job.cpp:440:22)>(void) () at /usr/src/contrib/llvm-project/llvm/include/llvm/ADT/STLFunctionalExtras.h:45
> #52 0x27d88624 in operator() () at /usr/src/contrib/llvm-project/llvm/include/llvm/ADT/STLFunctionalExtras.h:68
> #53 RunSafely () at /usr/src/contrib/llvm-project/llvm/lib/Support/CrashRecoveryContext.cpp:426
> #54 0x22786e90 in Execute () at /usr/src/contrib/llvm-project/clang/lib/Driver/Job.cpp:440
> #55 0x22748074 in ExecuteCommand () at /usr/src/contrib/llvm-project/clang/lib/Driver/Compilation.cpp:199
> #56 0x227483d0 in ExecuteJobs () at /usr/src/contrib/llvm-project/clang/lib/Driver/Compilation.cpp:253
> #57 0x22765bb8 in ExecuteCompilation () at /usr/src/contrib/llvm-project/clang/lib/Driver/Driver.cpp:1943
> #58 0x00037ba4 in clang_main () at /usr/src/contrib/llvm-project/clang/tools/driver/driver.cpp:391
> #59 0x000363a8 in main () at /usr/src/usr.bin/clang/clang/clang-driver.cpp:17

(gdb) list
165		assert(size > 0);
166		if (config_debug) {
167			/* Check the whole first page. */
168			size_t *p = (size_t *)addr;
169			for (size_t i = 0; i < PAGE / sizeof(size_t); i++) {
170				assert(p[i] == 0);
171			}

(gdb) x /1024x addr
0x2b629000:	0x00000000	0x00000000	0x00000000	0x00000000
0x2b629010:	0x00000000	0x00000000	0x00000000	0x00000000
0x2b629020:	0x00000000	0x00000000	0x00000000	0x00000000
. . .
0x2b629c10:	0x00000000	0x00000000	0x00000000	0x00000000
0x2b629c20:	0x00000000	0x00000000	0x00000000	0x00000000
0x2b629c30:	0x00000000	0x00000000	0x00000000	0x00000000
0x2b629c40:	0x5a5a5a5a	0x5a5a5a5a	0x5a5a5a5a	0x5a5a5a5a
0x2b629c50:	0x5a5a5a5a	0x5a5a5a5a	0x5a5a5a5a	0x5a5a5a5a
0x2b629c60:	0x5a5a5a5a	0x5a5a5a5a	0x5a5a5a5a	0x5a5a5a5a
. . .
0x2b629fd0:	0x5a5a5a5a	0x5a5a5a5a	0x5a5a5a5a	0x5a5a5a5a
0x2b629fe0:	0x5a5a5a5a	0x5a5a5a5a	0x5a5a5a5a	0x5a5a5a5a
0x2b629ff0:	0x5a5a5a5a	0x5a5a5a5a	0x5a5a5a5a	0x5a5a5a5a
(gdb) 

It has more 0x5a5a5a5a 's after that.

> For reference:
> 
> . . .
> Building /usr/obj/usr/src-investigation/arm.armv7/lib/clang/libclang/CodeGen/BackendUtil.pico
> . . .
> Building /usr/obj/usr/src-investigation/arm.armv7/lib/clang/libclang/CodeGen/CGDecl.pico
> <jemalloc>: /usr/src/contrib/jemalloc/include/jemalloc/internal/ehooks.h:170: Failed assertion: "p[i] == 0"
> . . .
> _ERROR_CMD='c++  -target armv7-gnueabihf-freebsd16.0 --sysroot=/usr/obj/usr/src-investigation/arm.armv7/tmp -B/usr/obj/usr/src-investigation/arm.armv7/tmp/usr/bin -fpic -DPIC  -UPIC -O2 -pipe -fno-common -I/usr/obj/usr/src-investigation/arm.armv7/lib/clang/libclang -I/usr/obj/usr/src-investigation/arm.armv7/lib/clang/libllvm -I/usr/src-investigation/contrib/llvm-project/clang/lib/Basic -I/usr/src-investigation/contrib/llvm-project/clang/lib/Driver -I/usr/src-investigation/contrib/llvm-project/clang/lib/CodeGen -I/usr/src-investigation/contrib/llvm-project/clang/include -DCLANG_ENABLE_ARCMT -DCLANG_ENABLE_STATIC_ANALYZER -I/usr/src-investigation/lib/clang/include -I/usr/src-investigation/contrib/llvm-project/llvm/include -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -DHAVE_VCS_VERSION_INC -DLLVM_DEFAULT_TARGET_TRIPLE=\"armv7-unknown-freebsd16.0-gnueabihf\" -DLLVM_HOST_TRIPLE=\"armv7-unknown-freebsd16.0\" -DDEFAULT_SYSROOT=\"\" -DLLVM_TARGET_ENABLE_AARCH64 -DLLVM_TARGET_ENABLE_ARM -DLLVM_TARGET_ENABLE_POWERPC -DLLVM_TARGET_ENABLE_RISCV -DLLVM_TARGET_ENABLE_X86 -DLLVM_NATIVE_ASMPARSER=LLVMInitializeARMAsmParser -DLLVM_NATIVE_ASMPRINTER=LLVMInitializeARMAsmPrinter -DLLVM_NATIVE_DISASSEMBLER=LLVMInitializeARMDisassembler -DLLVM_NATIVE_TARGET=LLVMInitializeARMTarget -DLLVM_NATIVE_TARGETINFO=LLVMInitializeARMTargetInfo -DLLVM_NATIVE_TARGETMC=LLVMInitializeARMTargetMC -ffunction-sections -fdata-sections -gline-tables-only -Wno-format-zero-length -fstack-protector-strong -Wdate-time -Wno-empty-body -Wno-string-plus-int -Wno-unused-const-variable -Wno-error=unused-but-set-parameter -Wno-error=cast-function-type-mismatch -Wno-tautological-compare -Wno-unused-value -Wno-parentheses-equality -Wno-unused-function -Wno-enum-conversion -Wno-unused-local-typedef -Wno-address-of-packed-member -Wno-switch -Wno-switch-enum -Wno-knr-promoted-parameter -Wno-parentheses -Qunused-arguments   -fno-exceptions -fno-rtti -gline-tables-only -std=c++17    -stdlib=libc++     -c /usr/src-investigation/contrib/llvm-project/clang/lib/CodeGen/BackendUtil.cpp -o CodeGen/BackendUtil.pico;'



===
Mark Millard
marklmi at yahoo.com