git/list[1] front-page[2] threads[3] people[4] search[5] about
 

Re: [PATCH 6/6] pack-bitmap.c: factor out `bitmap_index_seek_commit()`

From
Taylor Blau <me@ttaylorr.com>
Date
Mar 21, 2023, 18:16 UTC
Message-ID
<ZBn0iFE5qOJKVeel@nand.local>
In-Reply-To
<20230321181315.GH3119834@coredump.intra.peff.net>
On Tue, Mar 21, 2023 at 02:13:15PM -0400, Jeff King wrote:
> I'm not 100% sure on where these offsets come from. But it looks like
> they're coming from the bitmap lookup table. In which case a bogus value
> there should be an error(), and not a BUG(), I would think.

They do come from the lookup table, yes. I'm not sure that I agree that bogus values here should be an error() or a BUG(), or if I even have a strong preference between one and the other.

But I do think that trying to make it an error() makes it awkward for all of the other callers that want it to be a BUG(), since the detail of whether to call one or the other is private to bitmap_index_seek().

We *could* open-code it, introduce a variant of bitmap_index_seek(), make it take an additional parameter specifying whether to call one over the other, *or* check the bounds ourselves before even calling bitmap_index_seek().

But none of those seem like great options to me, TBH. I would be just as happy to leave this as a BUG(), to be honest.

Thanks, Taylor

Previous: Jeff KingNext: Jeff King
Message 27 of 29 in “pack-bitmap: miscellaneous mmap read hardening”
  1. 0/6 pack-bitmap: miscellaneous mmap read hardeningTaylor Blau, Mar 20, 2023
  2. 1/6 pack-bitmap.c: hide bitmap internals in `read_u8()`Taylor Blau, Mar 20, 2023
  3. Jeff KingMar 21, 2023
  4. Derrick StoleeMar 24, 2023
  5. 2/6 pack-bitmap.c: hide bitmap internals in `read_be32()`Taylor Blau, Mar 20, 2023
  6. 3/6 pack-bitmap.c: drop unnecessary 'inline'sTaylor Blau, Mar 20, 2023
  7. Jeff KingMar 21, 2023
  8. 4/6 pack-bitmap.c: factor out manual `map_pos` manipulationTaylor Blau, Mar 20, 2023
  9. Jeff KingMar 21, 2023
  10. Derrick StoleeMar 24, 2023
  11. Jeff KingMar 24, 2023
  12. Taylor BlauMar 24, 2023
  13. Jeff KingMar 25, 2023
  14. Taylor BlauMar 24, 2023
  15. Taylor BlauMar 24, 2023
  16. Taylor BlauMar 24, 2023
  17. 5/6 pack-bitmap.c: use `bitmap_index_seek()` where possibleTaylor Blau, Mar 20, 2023
  18. Jeff KingMar 21, 2023
  19. Derrick StoleeMar 24, 2023
  20. Jeff KingMar 24, 2023
  21. Junio C HamanoMar 24, 2023
  22. Jeff KingMar 24, 2023
  23. Junio C HamanoMar 24, 2023
  24. Taylor BlauMar 24, 2023
  25. 6/6 pack-bitmap.c: factor out `bitmap_index_seek_commit()`Taylor Blau, Mar 20, 2023
  26. Jeff KingMar 21, 2023
  27. Taylor BlauMar 21, 2023
  28. Jeff KingMar 21, 2023
  29. Derrick StoleeMar 24, 2023

Read the whole thread, see it on lore, or plain text.

$ cat FOOTERMessages come from the public archive at lore.kernel.org/git, fetched every hour. The front page is chosen and written each morning by an AI editor and can be wrong; the threads themselves are the record. About and API. For agents: an MCP server at https://gitlist.dev/mcp, and any thread, story or person page as Markdown by adding .md to its URL (or sending Accept: text/markdown). Details in /llms.txt.