Re: Still seeing Failed assertion: "p[i] == 0" on armv7 buildworld [Notes from another example core dump: #1]

[I misattributes a zero=flase to #15.]

On Nov 18, 2025, at 17:05, Mark Millard <[email protected]> wrote:

> [I came up with an addition type of note to have for these tests.]
> 
> On Nov 18, 2025, at 16:29, Mark Millard <[email protected]> wrote:
> 
>> I'm only sending notes from testing of how similar other failures appear
>> to the 2 lists. Folks can ask that I do otherwise for them if they want.
>> 
>> This one is for size 4096 (1 page). It looks like #0..#15 are similar to
>> the original report but #16 is not. #15 is for: arena_malloc
>> 
>> (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=0x2a80d000, size=size@entry=4096) 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=0xffff7b87, 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=4096, alignment=4096, zero=true, commit=0xffff7be7, 
>>   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=4096, 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=4096, 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=4096, 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=4096, 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=4096, alignment=<optimized out>, slab=true, szind=1, zero=<optimized out>, guarded=false, 
>>   deferred_work_generated=0xffff7caf) at jemalloc_pa.c:139
>> #11 0x2a16b9f8 in arena_slab_alloc (tsdn=tsdn@entry=0x2a2e4060, arena=0x2a600540, binind=1, binshard=0, bin_info=0x2a21fa8c <__je_bin_infos+48>) at jemalloc_arena.c:839
>> #12 0x2a16ac98 in __je_arena_cache_bin_fill_small (tsdn=0x2a2e4060, arena=0x2a600540, cache_bin=cache_bin@entry=0x2a2e42e8, cache_bin_info=0x2a6004c2, binind=1, nfill=100) 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=0x2a2e42e8, binind=1, 
>>   tcache_success=0xffff7d5f) at jemalloc_tcache.c:238
>> #14 0x2a15e538 in tcache_alloc_small (tsd=0x2a2e4060, arena=0x2a600540, tcache=0x2a2e42c8, size=16, binind=1, zero=false, slow_path=<optimized out>)
>>   at /usr/src/contrib/jemalloc/include/jemalloc/internal/tcache_inlines.h:68
>> #15 arena_malloc (tsdn=<optimized out>, arena=<optimized out>, size=<optimized out>, ind=<optimized out>, zero=<optimized out>, tcache=<optimized out>, slow_path=<optimized out>)
>>   at /usr/src/contrib/jemalloc/include/jemalloc/internal/arena_inlines_b.h:151
>> #16 iallocztm (tsdn=tsdn@entry=0x2a2e4060, size=<optimized out>, size@entry=16, ind=ind@entry=1, zero=false, tcache=0x2a2e42c8, is_internal=false, arena=0x0, slow_path=<optimized out>)
>>   at /usr/src/contrib/jemalloc/include/jemalloc/internal/jemalloc_internal_inlines_c.h:55
>> #17 0x2a164df4 in imalloc_no_sample (sopts=0xffff7dfc, dopts=0xffff7ddc, tsd=0x2a2e4060, size=16, usize=16, ind=<optimized out>) at jemalloc_jemalloc.c:2402
>> #18 imalloc_body (sopts=0xffff7dfc, dopts=0xffff7ddc, tsd=0x2a2e4060) at jemalloc_jemalloc.c:2577
>> #19 0x2a156188 in imalloc (sopts=sopts@entry=0xffff7dfc, dopts=<optimized out>, dopts@entry=0xffff7ddc) at jemalloc_jemalloc.c:2693
>> #20 0x2a156000 in __je_malloc_default (size=16) at jemalloc_jemalloc.c:2726
>> #21 0x29e61990 in operator_new_impl (size=16) at /usr/src/contrib/llvm-project/libcxx/src/new.cpp:34
>> #22 operator new (size=<optimized out>) at /usr/src/contrib/llvm-project/libcxx/src/new.cpp:47
>> #23 0x27e101d0 in __libcpp_operator_new<unsigned int> () at /usr/obj/usr/src/arm.armv7/tmp/usr/include/c++/v1/new:265
>> #24 __libcpp_allocate () at /usr/obj/usr/src/arm.armv7/tmp/usr/include/c++/v1/new:289
>> #25 allocate () at /usr/obj/usr/src/arm.armv7/tmp/usr/include/c++/v1/__memory/allocator.h:118
>> #26 __allocate_at_least<std::__1::allocator<char> > () at /usr/obj/usr/src/arm.armv7/tmp/usr/include/c++/v1/__memory/allocate_at_least.h:41
>> #27 __init () at /usr/obj/usr/src/arm.armv7/tmp/usr/include/c++/v1/string:2336
>> #28 basic_string () at /usr/obj/usr/src/arm.armv7/tmp/usr/include/c++/v1/string:1078
>> #29 str () at /usr/src/contrib/llvm-project/llvm/include/llvm/ADT/StringRef.h:217
>> #30 str () at /usr/src/contrib/llvm-project/llvm/lib/Support/Twine.cpp:29
>> #31 0x294076d0 in SetNamePrefix () at /usr/src/contrib/llvm-project/llvm/lib/Transforms/Scalar/SROA.cpp:502
>> #32 visit () at /usr/src/contrib/llvm-project/llvm/lib/Transforms/Scalar/SROA.cpp:2734
>> #33 0x293f4938 in rewritePartition () at /usr/src/contrib/llvm-project/llvm/lib/Transforms/Scalar/SROA.cpp:4893
>> #34 splitAlloca () at /usr/src/contrib/llvm-project/llvm/lib/Transforms/Scalar/SROA.cpp:5284
>> #35 0x293f04ec in runOnAlloca () at /usr/src/contrib/llvm-project/llvm/lib/Transforms/Scalar/SROA.cpp:5485
>> #36 0x293ebfc0 in runSROA () at /usr/src/contrib/llvm-project/llvm/lib/Transforms/Scalar/SROA.cpp:5596
>> #37 0x293eba80 in run () at /usr/src/contrib/llvm-project/llvm/lib/Transforms/Scalar/SROA.cpp:5637
>> #38 0x27b9b32c in llvm::detail::PassModel<llvm::Function, llvm::SROAPass, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) ()
>>   at /usr/src/contrib/llvm-project/llvm/include/llvm/IR/PassManagerInternal.h:90
>> #39 0x276eef80 in run () at /usr/src/contrib/llvm-project/llvm/include/llvm/IR/PassManagerImpl.h:81
>> #40 0x2217fd38 in llvm::detail::PassModel<llvm::Function, llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) () at /usr/src/contrib/llvm-project/llvm/include/llvm/IR/PassManagerInternal.h:90
>> #41 0x276f30e4 in run () at /usr/src/contrib/llvm-project/llvm/lib/IR/PassManager.cpp:124
>> #42 0x22178b88 in llvm::detail::PassModel<llvm::Module, llvm::ModuleToFunctionPassAdaptor, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) ()
>>   at /usr/src/contrib/llvm-project/llvm/include/llvm/IR/PassManagerInternal.h:90
>> #43 0x276ee244 in run () at /usr/src/contrib/llvm-project/llvm/include/llvm/IR/PassManagerImpl.h:81
>> #44 0x22174ffc in RunOptimizationPipeline () at /usr/src/contrib/llvm-project/clang/lib/CodeGen/BackendUtil.cpp:1114
>> #45 0x2216cfb8 in EmitAssembly () at /usr/src/contrib/llvm-project/clang/lib/CodeGen/BackendUtil.cpp:1179
>> --Type <RET> for more, q to quit, c to continue without paging--
>> #46 EmitBackendOutput () at /usr/src/contrib/llvm-project/clang/lib/CodeGen/BackendUtil.cpp:1341
>> #47 0x225cbca0 in HandleTranslationUnit () at /usr/src/contrib/llvm-project/clang/lib/CodeGen/CodeGenAction.cpp:354
>> #48 0x22cff8e4 in ParseAST () at /usr/src/contrib/llvm-project/clang/lib/Parse/ParseAST.cpp:184
>> #49 0x22b5a7b8 in Execute () at /usr/src/contrib/llvm-project/clang/lib/Frontend/FrontendAction.cpp:1078
>> #50 0x22adb800 in ExecuteAction () at /usr/src/contrib/llvm-project/clang/lib/Frontend/CompilerInstance.cpp:1061
>> #51 0x22bf6a90 in ExecuteCompilerInvocation () at /usr/src/contrib/llvm-project/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:280
>> #52 0x0002afc8 in cc1_main () at /usr/src/contrib/llvm-project/clang/tools/driver/cc1_main.cpp:284
>> #53 0x00038548 in ExecuteCC1Tool () at /usr/src/contrib/llvm-project/clang/tools/driver/driver.cpp:215
>> #54 0x227877ec in operator() () at /usr/src/contrib/llvm-project/llvm/include/llvm/ADT/STLFunctionalExtras.h:68
>> #55 operator() () at /usr/src/contrib/llvm-project/clang/lib/Driver/Job.cpp:440
>> #56 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
>> #57 0x27d88624 in operator() () at /usr/src/contrib/llvm-project/llvm/include/llvm/ADT/STLFunctionalExtras.h:68
>> #58 RunSafely () at /usr/src/contrib/llvm-project/llvm/lib/Support/CrashRecoveryContext.cpp:426
>> #59 0x22786e90 in Execute () at /usr/src/contrib/llvm-project/clang/lib/Driver/Job.cpp:440
>> #60 0x22748074 in ExecuteCommand () at /usr/src/contrib/llvm-project/clang/lib/Driver/Compilation.cpp:199
>> #61 0x227483d0 in ExecuteJobs () at /usr/src/contrib/llvm-project/clang/lib/Driver/Compilation.cpp:253
>> #62 0x22765bb8 in ExecuteCompilation () at /usr/src/contrib/llvm-project/clang/lib/Driver/Driver.cpp:1943
>> #63 0x00037ba4 in clang_main () at /usr/src/contrib/llvm-project/clang/tools/driver/driver.cpp:391
>> #64 0x000363a8 in main () at /usr/src/usr.bin/clang/clang/clang-driver.cpp:17
>> 
>> 0x2a80cfd0: 0x000013f2 0x00000079 0xffffffff 0xa5a5a5a5
>> 0x2a80cfe0: 0xffffffff 0xa5a5a5a5 0xffffffff 0xa5a5a5a5
>> 0x2a80cff0: 0x000014a6 0x00000079 0xffffffff 0xa5a5a5a5
>> (gdb) x /1024x (size_t*)addr
>> 0x2a80d000: 0x5a5a5a5a 0x5a5a5a5a 0x5a5a5a5a 0x5a5a5a5a
>> 0x2a80d010: 0x5a5a5a5a 0x5a5a5a5a 0x5a5a5a5a 0x5a5a5a5a
>> 0x2a80d020: 0x5a5a5a5a 0x5a5a5a5a 0x5a5a5a5a 0x5a5a5a5a
>> . . .
>> 0x2a80dfd0: 0x5a5a5a5a 0x5a5a5a5a 0x5a5a5a5a 0x5a5a5a5a
>> 0x2a80dfe0: 0x5a5a5a5a 0x5a5a5a5a 0x5a5a5a5a 0x5a5a5a5a
>> 0x2a80dff0: 0x5a5a5a5a 0x5a5a5a5a 0x5a5a5a5a 0x5a5a5a5a
>> (gdb) x /1024x ((size_t*)addr)+1024
>> 0x2a80e000: 0x00000051 0x00000002 0x29e862b8 0xa5a5a5a5
>> 0x2a80e010: 0x7273752f 0x6372732f 0x766e692d 0x69747365
>> 0x2a80e020: 0x69746167 0x6c2f6e6f 0x632f6269 0x676e616c
>> 0x2a80e030: 0x636e692f 0x6564756c 0x745f5f2f 0x5f657079
>> 
>> So: All of the page was 0x5a5a5a5a repeated. Before and after
>> had some other values and were accessible.
>> 
> 
> For #0..#15: The original example and the above
> agree about:
> 
> #5  __je_extent_alloc_wrapper zero=true
> #14 tcache_alloc_small        zero=false
> #15 __je_extent_alloc_wrapper zero=false

#15 was actually optimized out. It was #16 that
was zero=false. (But that is outside the common
range #0..#15.)

> (The others are optimized out.)
> 



===
Mark Millard
marklmi at yahoo.com