Re: [PATCH v1 4/7] perf maps: Check map__start_cmp() in __maps__insert()

[sashiko-bot@kernel.org]

> In __maps__insert(), maps_by_address_sorted is kept true if the previous
> map's end is less than or equal to the new map's start. However, when a
> map has an end of 0 (for example, an unmapped [0, 0) map or a map whose
> end has not been set yet) and a [0, 0) map is inserted after it,
> map__end(prev) <= map__start(new) evaluates to 0 <= 0 (true) even when
> map__start_cmp(&prev, &new) > 0 (either because map__start(prev) > 0 or
> because prev's pointer address is greater than new's pointer address).
> This leaves maps_by_address_sorted set to true on an array that is not
> ordered according to map__start_cmp(), causing bsearch() in
> maps__by_address_index() to fail and return -1 during __maps__remove().
> 
> Also check map__start_cmp(&maps_by_address[nr_maps - 2], &new) <= 0 when
> updating maps_by_address_sorted in __maps__insert().
> 
> Fixes: 659ad3492b91 ("perf maps: Switch from rbtree to lazily sorted array for addresses")
> Signed-off-by: Ian Rogers <irogers@google.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261025220349.1244499-1-irogers@google.com?part=4