microsoft / microsoft/mimalloc

Confusing debug prints

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#360 11 commenti 1 reazione 0 assegnatari Vedi su GitHub

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Lingua principale
C
Stelle
13.4k
Fork
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Merge medio
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PR unite (30g)
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Descrizione

When allocating & deleting small memory blocks sequentially, some confusing debug prints appear randomly. The debug message says "pointer might not point to a valid heap region" and "this may be still valid very large allocation (over 64MiB)" but my allocations always smaller than 300 bytes.

Should I ignore this message or it is a bug or am I using the library incorrectly?

alloc 272 [0000040000030140]
alloc 16 [00000400000102E0]
alloc 16 [0000040000010300]
alloc 16 [0000040000010320]
alloc 40 [00000400000400C0]
alloc 16 [0000040000010340]
alloc 16 [0000040000010360]
alloc 16 [0000040000010380]
delete 16 [0000040000010380]
alloc 8 [0000040000001550]
alloc 4 [0000040000001560]
alloc 8 [0000040000001570]
alloc 4 [0000040000001580]
delete 64 [0000040000020050]
delete 16 [0000040000010020]
delete 64 [0000040000020000]
delete 16 [0000040000010000]
> mimalloc: warning: mi_usable_size: pointer might not point to a valid heap region: 0000040000080000
> (this may still be a valid very large allocation (over 64MiB))
> mimalloc: warning: (yes, the previous pointer 0000040000080000 was valid after all)
> mimalloc: warning: mi_usable_size: pointer might not point to a valid heap region: 0000040000080000
> (this may still be a valid very large allocation (over 64MiB))
> mimalloc: warning: (yes, the previous pointer 0000040000080000 was valid after all)
alloc 248 [0000040000080000]
> mimalloc: warning: mi_usable_size: pointer might not point to a valid heap region: 00000400000400F0
> (this may still be a valid very large allocation (over 64MiB))
> mimalloc: warning: (yes, the previous pointer 00000400000400F0 was valid after all)
> mimalloc: warning: mi_usable_size: pointer might not point to a valid heap region: 00000400000400F0
> (this may still be a valid very large allocation (over 64MiB))
> mimalloc: warning: (yes, the previous pointer 00000400000400F0 was valid after all)
alloc 32 [00000400000400F0]
> mimalloc: warning: mi_usable_size: pointer might not point to a valid heap region: 00000400000103A0
> (this may still be a valid very large allocation (over 64MiB))
> mimalloc: warning: (yes, the previous pointer 00000400000103A0 was valid after all)
> mimalloc: warning: mi_usable_size: pointer might not point to a valid heap region: 00000400000103A0
> (this may still be a valid very large allocation (over 64MiB))
> mimalloc: warning: (yes, the previous pointer 00000400000103A0 was valid after all)
alloc 16 [00000400000103A0]
> mimalloc: warning: mi_usable_size: pointer might not point to a valid heap region: 0000040000040120
> (this may still be a valid very large allocation (over 64MiB))
> mimalloc: warning: (yes, the previous pointer 0000040000040120 was valid after all)
> mimalloc: warning: mi_usable_size: pointer might not point to a valid heap region: 0000040000040120
> (this may still be a valid very large allocation (over 64MiB))
> mimalloc: warning: (yes, the previous pointer 0000040000040120 was valid after all)
alloc 32 [0000040000040120]
> mimalloc: warning: mi_usable_size: pointer might not point to a valid heap region: 00000400000103C0
> (this may still be a valid very large allocation (over 64MiB))
alloc 16 [00000400000103C0]
delete 16 [00000400000103C0]
alloc 16 [00000400000103E0]
alloc 64 [0000040000020190]
alloc 16 [0000040000010400]
delete 16 [0000040000010400]
delete 32 [0000040000040120]
delete 16 [00000400000103A0]
delete 32 [00000400000400F0]
delete 248 [0000040000080000]
alloc 248 [0000040000080100]

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Direzione di ricerca

Inizia riproducendo il pattern sequenziale di piccole allocazioni e tracciando il percorso dell’avviso di mi_usable_size. Determina perché puntatori piccoli validi attivano l’avviso di allocazione grande, quindi verifica che gli avvisi non compaiano più erroneamente oppure che il loro comportamento sia documentato. L’issue non indica file sorgente né test.

Scritto dal modello di indicizzazione a partire dal testo della issue.

Valutazione

Stack tecnologico
c
Ambito
operating-systems
Tipo di issue
Bug
Difficoltà
4/5
Tempo stimato
3-5 giorni
Stato di attività
Ferma
Chiarezza
Da chiarire
Idoneità per principianti
25/100

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