From: Junio C Hamano <gitster@pobox•com>
To: Patrick Steinhardt <ps@pks•im>
Cc: git@vger•kernel.org, Edward Thomson <ethomson@edwardthomson•com>
Subject: Re: [PATCH v2 04/22] reftable/basics: handle allocation failures in `reftable_calloc()`
Date: Tue, 24 Sep 2024 09:59:24 -0700 [thread overview]
Message-ID: <xmqqikulugwj.fsf@gitster.g> (raw)
In-Reply-To: <f6ad92ffd01c442dacd3ac6aa448891028636636.1727158127.git.ps@pks.im> (Patrick Steinhardt's message of "Tue, 24 Sep 2024 08:32:00 +0200")
Patrick Steinhardt <ps@pks•im> writes:
> void *reftable_calloc(size_t nelem, size_t elsize)
> {
> - size_t sz = st_mult(nelem, elsize);
> - void *p = reftable_malloc(sz);
> - memset(p, 0, sz);
> + void *p;
> +
> + if (nelem && elsize > SIZE_MAX / nelem)
> + return NULL;
Now it is open coded, it strikes me that the check is a bit overly
conservative.
If we are trying to allocate slightly than half of SIZE_MAX by
asking elsize==1 and nelem==(SIZE_MAX / 2 + 10), we'd say that
(elsize * nelem) would not fit size_t and fail the allocation.
For the purpose of this caller, it is not a practical issue, as it
is likely that you'd not be able to obtain slightly more than half
your address space out of a single allocation anyway.
But it illustrates why open coding is not necessarily an excellent
idea in the longer term, doesn't it? When unsigned_mult_overflows()
is updated to avoid such a false positive, how would we remember
that we need to update this copy we?
> + p = reftable_malloc(nelem * elsize);
> + if (!p)
> + return NULL;
> +
> + memset(p, 0, nelem * elsize);
> return p;
> }
next prev parent reply other threads:[~2024-09-24 16:59 UTC|newest]
Thread overview: 151+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-16 12:28 [PATCH 00/22] reftable: handle allocation errors Patrick Steinhardt
2024-09-16 12:28 ` [PATCH 01/22] reftable/error: introduce out-of-memory error code Patrick Steinhardt
2024-09-16 12:28 ` [PATCH 02/22] reftable/basics: merge "publicbasics" into "basics" Patrick Steinhardt
2024-09-16 12:28 ` [PATCH 03/22] reftable: introduce `reftable_strdup()` Patrick Steinhardt
2024-09-16 12:28 ` [PATCH 04/22] reftable/basics: handle allocation failures in `reftable_calloc()` Patrick Steinhardt
2024-09-21 19:37 ` Junio C Hamano
2024-09-24 5:48 ` Patrick Steinhardt
2024-09-24 6:02 ` Patrick Steinhardt
2024-09-24 16:39 ` Junio C Hamano
2024-09-16 12:28 ` [PATCH 05/22] reftable/basics: handle allocation failures in `parse_names()` Patrick Steinhardt
2024-09-16 12:28 ` [PATCH 06/22] reftable/record: handle allocation failures on copy Patrick Steinhardt
2024-09-16 12:28 ` [PATCH 07/22] reftable/record: handle allocation failures when decoding records Patrick Steinhardt
2024-09-16 12:28 ` [PATCH 08/22] reftable/writer: handle allocation failures in `writer_index_hash()` Patrick Steinhardt
2024-09-16 12:28 ` [PATCH 09/22] reftable/writer: handle allocation failures in `reftable_new_writer()` Patrick Steinhardt
2024-09-16 12:28 ` [PATCH 10/22] reftable/merged: handle allocation failures in `merged_table_init_iter()` Patrick Steinhardt
2024-09-16 12:28 ` [PATCH 11/22] reftable/reader: handle allocation failures for unindexed reader Patrick Steinhardt
2024-09-16 12:28 ` [PATCH 12/22] reftable/reader: handle allocation failures in `reader_init_iter()` Patrick Steinhardt
2024-09-16 12:28 ` [PATCH 13/22] reftable/stack: handle allocation failures on reload Patrick Steinhardt
2024-09-16 12:28 ` [PATCH 14/22] reftable/stack: handle allocation failures in `reftable_new_stack()` Patrick Steinhardt
2024-09-16 12:29 ` [PATCH 15/22] reftable/stack: handle allocation failures in `stack_compact_range()` Patrick Steinhardt
2024-09-16 12:29 ` [PATCH 16/22] reftable/stack: handle allocation failures in auto compaction Patrick Steinhardt
2024-09-16 12:29 ` [PATCH 17/22] reftable/iter: handle allocation failures when creating indexed table iter Patrick Steinhardt
2024-09-22 6:26 ` Junio C Hamano
2024-09-24 5:49 ` Patrick Steinhardt
2024-09-16 12:29 ` [PATCH 18/22] reftable/blocksource: handle allocation failures Patrick Steinhardt
2024-09-16 12:29 ` [PATCH 19/22] reftable/block: " Patrick Steinhardt
2024-09-16 12:29 ` [PATCH 20/22] reftable/pq: handle allocation failures when adding entries Patrick Steinhardt
2024-09-16 12:29 ` [PATCH 21/22] reftable/tree: handle allocation failures Patrick Steinhardt
2024-09-16 12:29 ` [PATCH 22/22] reftable: handle trivial " Patrick Steinhardt
2024-09-24 6:31 ` [PATCH v2 00/22] reftable: handle allocation errors Patrick Steinhardt
2024-09-24 6:31 ` [PATCH v2 01/22] reftable/error: introduce out-of-memory error code Patrick Steinhardt
2024-09-24 6:31 ` [PATCH v2 02/22] reftable/basics: merge "publicbasics" into "basics" Patrick Steinhardt
2024-09-24 6:31 ` [PATCH v2 03/22] reftable: introduce `reftable_strdup()` Patrick Steinhardt
2024-09-24 6:32 ` [PATCH v2 04/22] reftable/basics: handle allocation failures in `reftable_calloc()` Patrick Steinhardt
2024-09-24 16:59 ` Junio C Hamano [this message]
2024-09-26 12:11 ` Patrick Steinhardt
2024-09-26 16:13 ` Junio C Hamano
2024-09-27 5:28 ` Patrick Steinhardt
2024-09-27 12:21 ` Han-Wen Nienhuys
2024-09-27 15:21 ` Junio C Hamano
2024-09-24 6:32 ` [PATCH v2 05/22] reftable/basics: handle allocation failures in `parse_names()` Patrick Steinhardt
2024-09-24 22:19 ` René Scharfe
2024-09-26 12:09 ` Patrick Steinhardt
2024-09-24 6:32 ` [PATCH v2 06/22] reftable/record: handle allocation failures on copy Patrick Steinhardt
2024-09-24 6:32 ` [PATCH v2 07/22] reftable/record: handle allocation failures when decoding records Patrick Steinhardt
2024-09-24 6:32 ` [PATCH v2 08/22] reftable/writer: handle allocation failures in `writer_index_hash()` Patrick Steinhardt
2024-09-24 6:32 ` [PATCH v2 09/22] reftable/writer: handle allocation failures in `reftable_new_writer()` Patrick Steinhardt
2024-09-24 6:32 ` [PATCH v2 10/22] reftable/merged: handle allocation failures in `merged_table_init_iter()` Patrick Steinhardt
2024-09-24 6:32 ` [PATCH v2 11/22] reftable/reader: handle allocation failures for unindexed reader Patrick Steinhardt
2024-09-24 6:32 ` [PATCH v2 12/22] reftable/reader: handle allocation failures in `reader_init_iter()` Patrick Steinhardt
2024-09-24 6:32 ` [PATCH v2 13/22] reftable/stack: handle allocation failures on reload Patrick Steinhardt
2024-09-24 6:32 ` [PATCH v2 14/22] reftable/stack: handle allocation failures in `reftable_new_stack()` Patrick Steinhardt
2024-09-24 6:32 ` [PATCH v2 15/22] reftable/stack: handle allocation failures in `stack_compact_range()` Patrick Steinhardt
2024-09-24 6:32 ` [PATCH v2 16/22] reftable/stack: handle allocation failures in auto compaction Patrick Steinhardt
2024-09-24 6:32 ` [PATCH v2 17/22] reftable/iter: handle allocation failures when creating indexed table iter Patrick Steinhardt
2024-09-24 6:32 ` [PATCH v2 18/22] reftable/blocksource: handle allocation failures Patrick Steinhardt
2024-09-24 6:32 ` [PATCH v2 19/22] reftable/block: " Patrick Steinhardt
2024-09-24 6:32 ` [PATCH v2 20/22] reftable/pq: handle allocation failures when adding entries Patrick Steinhardt
2024-09-24 6:33 ` [PATCH v2 21/22] reftable/tree: handle allocation failures Patrick Steinhardt
2024-09-24 6:33 ` [PATCH v2 22/22] reftable: handle trivial " Patrick Steinhardt
2024-09-30 8:08 ` [PATCH v3 00/22] refatble: handle allocation errors Patrick Steinhardt
2024-09-30 8:08 ` [PATCH v3 01/22] reftable/error: introduce out-of-memory error code Patrick Steinhardt
2024-09-30 8:08 ` [PATCH v3 02/22] reftable/basics: merge "publicbasics" into "basics" Patrick Steinhardt
2024-09-30 8:08 ` [PATCH v3 03/22] reftable: introduce `reftable_strdup()` Patrick Steinhardt
2024-09-30 8:08 ` [PATCH v3 04/22] reftable/basics: handle allocation failures in `reftable_calloc()` Patrick Steinhardt
2024-09-30 8:08 ` [PATCH v3 05/22] reftable/basics: handle allocation failures in `parse_names()` Patrick Steinhardt
2024-09-30 17:40 ` René Scharfe
2024-09-30 8:08 ` [PATCH v3 06/22] reftable/record: handle allocation failures on copy Patrick Steinhardt
2024-09-30 8:08 ` [PATCH v3 07/22] reftable/record: handle allocation failures when decoding records Patrick Steinhardt
2024-09-30 8:08 ` [PATCH v3 08/22] reftable/writer: handle allocation failures in `writer_index_hash()` Patrick Steinhardt
2024-09-30 8:08 ` [PATCH v3 09/22] reftable/writer: handle allocation failures in `reftable_new_writer()` Patrick Steinhardt
2024-09-30 17:40 ` René Scharfe
2024-09-30 18:22 ` Patrick Steinhardt
2024-09-30 19:11 ` Junio C Hamano
2024-09-30 8:08 ` [PATCH v3 10/22] reftable/merged: handle allocation failures in `merged_table_init_iter()` Patrick Steinhardt
2024-09-30 8:08 ` [PATCH v3 11/22] reftable/reader: handle allocation failures for unindexed reader Patrick Steinhardt
2024-09-30 8:08 ` [PATCH v3 12/22] reftable/reader: handle allocation failures in `reader_init_iter()` Patrick Steinhardt
2024-09-30 8:08 ` [PATCH v3 13/22] reftable/stack: handle allocation failures on reload Patrick Steinhardt
2024-09-30 8:08 ` [PATCH v3 14/22] reftable/stack: handle allocation failures in `reftable_new_stack()` Patrick Steinhardt
2024-09-30 8:08 ` [PATCH v3 15/22] reftable/stack: handle allocation failures in `stack_compact_range()` Patrick Steinhardt
2024-09-30 8:08 ` [PATCH v3 16/22] reftable/stack: handle allocation failures in auto compaction Patrick Steinhardt
2024-09-30 8:09 ` [PATCH v3 17/22] reftable/iter: handle allocation failures when creating indexed table iter Patrick Steinhardt
2024-09-30 8:09 ` [PATCH v3 18/22] reftable/blocksource: handle allocation failures Patrick Steinhardt
2024-09-30 8:09 ` [PATCH v3 19/22] reftable/block: " Patrick Steinhardt
2024-09-30 8:09 ` [PATCH v3 20/22] reftable/pq: handle allocation failures when adding entries Patrick Steinhardt
2024-09-30 8:09 ` [PATCH v3 21/22] reftable/tree: handle allocation failures Patrick Steinhardt
2024-09-30 8:09 ` [PATCH v3 22/22] reftable: handle trivial " Patrick Steinhardt
2024-09-30 18:18 ` [PATCH v3 00/22] refatble: handle allocation errors Junio C Hamano
2024-10-01 9:41 ` [PATCH v4 00/25] reftable: " Patrick Steinhardt
2024-10-01 9:41 ` [PATCH v4 01/25] reftable/error: introduce out-of-memory error code Patrick Steinhardt
2024-10-01 9:41 ` [PATCH v4 02/25] reftable/basics: merge "publicbasics" into "basics" Patrick Steinhardt
2024-10-01 9:41 ` [PATCH v4 03/25] reftable: introduce `reftable_strdup()` Patrick Steinhardt
2024-10-01 9:41 ` [PATCH v4 04/25] reftable/basics: handle allocation failures in `reftable_calloc()` Patrick Steinhardt
2024-10-01 9:41 ` [PATCH v4 05/25] reftable/basics: handle allocation failures in `parse_names()` Patrick Steinhardt
2024-10-01 9:42 ` [PATCH v4 06/25] reftable/record: handle allocation failures on copy Patrick Steinhardt
2024-10-01 9:42 ` [PATCH v4 07/25] reftable/record: handle allocation failures when decoding records Patrick Steinhardt
2024-10-01 9:42 ` [PATCH v4 08/25] reftable/writer: handle allocation failures in `writer_index_hash()` Patrick Steinhardt
2024-10-01 9:42 ` [PATCH v4 09/25] reftable/writer: handle allocation failures in `reftable_new_writer()` Patrick Steinhardt
2024-10-01 9:42 ` [PATCH v4 10/25] reftable/merged: handle allocation failures in `merged_table_init_iter()` Patrick Steinhardt
2024-10-01 9:42 ` [PATCH v4 11/25] reftable/reader: handle allocation failures for unindexed reader Patrick Steinhardt
2024-10-01 9:42 ` [PATCH v4 12/25] reftable/reader: handle allocation failures in `reader_init_iter()` Patrick Steinhardt
2024-10-01 9:42 ` [PATCH v4 13/25] reftable/stack: handle allocation failures on reload Patrick Steinhardt
2024-10-01 9:42 ` [PATCH v4 14/25] reftable/stack: handle allocation failures in `reftable_new_stack()` Patrick Steinhardt
2024-10-01 9:42 ` [PATCH v4 15/25] reftable/stack: handle allocation failures in `stack_compact_range()` Patrick Steinhardt
2024-10-01 9:42 ` [PATCH v4 16/25] reftable/stack: handle allocation failures in auto compaction Patrick Steinhardt
2024-10-01 9:42 ` [PATCH v4 17/25] reftable/iter: handle allocation failures when creating indexed table iter Patrick Steinhardt
2024-10-01 9:42 ` [PATCH v4 18/25] reftable/blocksource: handle allocation failures Patrick Steinhardt
2024-10-01 9:42 ` [PATCH v4 19/25] reftable/block: " Patrick Steinhardt
2024-10-01 9:42 ` [PATCH v4 20/25] reftable/pq: handle allocation failures when adding entries Patrick Steinhardt
2024-10-01 9:42 ` [PATCH v4 21/25] reftable/tree: handle allocation failures Patrick Steinhardt
2024-10-01 9:42 ` [PATCH v4 22/25] reftable: handle trivial " Patrick Steinhardt
2024-10-01 9:42 ` [PATCH v4 23/25] reftable: fix calls to free(3P) Patrick Steinhardt
2024-10-01 9:43 ` [PATCH v4 24/25] reftable: introduce `REFTABLE_FREE_AND_NULL()` Patrick Steinhardt
2024-10-01 9:43 ` [PATCH v4 25/25] reftable/basics: ban standard allocator functions Patrick Steinhardt
2024-10-01 22:50 ` Junio C Hamano
2024-10-02 4:30 ` Patrick Steinhardt
2024-10-01 17:52 ` [PATCH v4 00/25] reftable: handle allocation errors Junio C Hamano
2024-10-01 18:30 ` René Scharfe
2024-10-01 19:25 ` Junio C Hamano
2024-10-02 4:29 ` Patrick Steinhardt
2024-10-02 18:04 ` Junio C Hamano
2024-10-02 10:55 ` [PATCH v5 " Patrick Steinhardt
2024-10-02 10:55 ` [PATCH v5 01/25] reftable/error: introduce out-of-memory error code Patrick Steinhardt
2024-10-02 10:55 ` [PATCH v5 02/25] reftable/basics: merge "publicbasics" into "basics" Patrick Steinhardt
2024-10-02 10:55 ` [PATCH v5 03/25] reftable: introduce `reftable_strdup()` Patrick Steinhardt
2024-10-02 10:55 ` [PATCH v5 04/25] reftable/basics: handle allocation failures in `reftable_calloc()` Patrick Steinhardt
2024-10-02 10:55 ` [PATCH v5 05/25] reftable/basics: handle allocation failures in `parse_names()` Patrick Steinhardt
2024-10-02 22:07 ` Eric Sunshine
2024-10-04 4:58 ` Patrick Steinhardt
2024-10-04 5:43 ` Eric Sunshine
2024-10-02 10:55 ` [PATCH v5 06/25] reftable/record: handle allocation failures on copy Patrick Steinhardt
2024-10-02 10:55 ` [PATCH v5 07/25] reftable/record: handle allocation failures when decoding records Patrick Steinhardt
2024-10-02 10:55 ` [PATCH v5 08/25] reftable/writer: handle allocation failures in `writer_index_hash()` Patrick Steinhardt
2024-10-02 10:55 ` [PATCH v5 09/25] reftable/writer: handle allocation failures in `reftable_new_writer()` Patrick Steinhardt
2024-10-02 10:55 ` [PATCH v5 10/25] reftable/merged: handle allocation failures in `merged_table_init_iter()` Patrick Steinhardt
2024-10-02 10:55 ` [PATCH v5 11/25] reftable/reader: handle allocation failures for unindexed reader Patrick Steinhardt
2024-10-02 10:55 ` [PATCH v5 12/25] reftable/reader: handle allocation failures in `reader_init_iter()` Patrick Steinhardt
2024-10-02 10:56 ` [PATCH v5 13/25] reftable/stack: handle allocation failures on reload Patrick Steinhardt
2024-10-02 10:56 ` [PATCH v5 14/25] reftable/stack: handle allocation failures in `reftable_new_stack()` Patrick Steinhardt
2024-10-02 10:56 ` [PATCH v5 15/25] reftable/stack: handle allocation failures in `stack_compact_range()` Patrick Steinhardt
2024-10-02 10:56 ` [PATCH v5 16/25] reftable/stack: handle allocation failures in auto compaction Patrick Steinhardt
2024-10-02 10:56 ` [PATCH v5 17/25] reftable/iter: handle allocation failures when creating indexed table iter Patrick Steinhardt
2024-10-02 10:56 ` [PATCH v5 18/25] reftable/blocksource: handle allocation failures Patrick Steinhardt
2024-10-02 10:56 ` [PATCH v5 19/25] reftable/block: " Patrick Steinhardt
2024-10-02 10:56 ` [PATCH v5 20/25] reftable/pq: handle allocation failures when adding entries Patrick Steinhardt
2024-10-02 10:56 ` [PATCH v5 21/25] reftable/tree: handle allocation failures Patrick Steinhardt
2024-10-02 10:56 ` [PATCH v5 22/25] reftable: handle trivial " Patrick Steinhardt
2024-10-02 10:56 ` [PATCH v5 23/25] reftable: fix calls to free(3P) Patrick Steinhardt
2024-10-02 10:56 ` [PATCH v5 24/25] reftable: introduce `REFTABLE_FREE_AND_NULL()` Patrick Steinhardt
2024-10-02 10:56 ` [PATCH v5 25/25] reftable/basics: ban standard allocator functions Patrick Steinhardt
2024-10-02 19:32 ` [PATCH v5 00/25] reftable: handle allocation errors Junio C Hamano
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