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use st_update to prevent table extension

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to prevent the following scenario:

1. `delete_unique_str()` can be called while GC (sweeping)
2. it calls `st_insert()` to decrement the counter
3. `st_insert()` can try to extend the table even if the key exists
4. `xmalloc` while GC and cause BUG
This commit is contained in:
Koichi Sasada 2024-12-20 17:42:53 +09:00
parent 60c814607d
commit c695536cc8
Notes: git 2024-12-23 02:10:41 +00:00 
Merged: https://github.com/ruby/ruby/pull/12407
1 changed files with 9 additions and 1 deletions
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10
ext/objspace/object_tracing.c
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@ -53,6 +53,14 @@ make_unique_str(st_table *tbl, const char *str, long len)
}
}
static int
delete_unique_str_dec(st_data_t *key, st_data_t *value, st_data_t arg, int existing)
{
assert(existing);
*value = arg;
return ST_CONTINUE;
}
static void
delete_unique_str(st_table *tbl, const char *str)
{
@ -66,7 +74,7 @@ delete_unique_str(st_table *tbl, const char *str)
ruby_xfree((char *)n);
}
else {
st_insert(tbl, (st_data_t)str, n-1);
st_update(tbl, (st_data_t)str, delete_unique_str_dec, (st_data_t)(n-1));
}
}
}