Re: [PATCH v2] lib: fix data race in rhashtable_rehash_one

[Herbert Xu]

Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote:
> rhashtable_rehash_one() uses complex logic to update entry->next field,
> after INIT_RHT_NULLS_HEAD and NULLS_MARKER expansion:
> 
> entry->next = 1 | ((base + off) << 1)
> 
> This can be compiled along the lines of:
> 
> entry->next = base + off
> entry->next <<= 1
> entry->next |= 1
> 
> Which will break concurrent readers.
> 
> NULLS value recomputation is not needed here, so just remove
> the complex logic.
> 
> The data race was found with KernelThreadSanitizer (KTSAN).
> 
> Signed-off-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>

Acked-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/