Modules: fixed double-free in shared dict update with eviction.#1041
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xeioex wants to merge 1 commit intonginx:masterfrom
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Modules: fixed double-free in shared dict update with eviction.#1041xeioex wants to merge 1 commit intonginx:masterfrom
xeioex wants to merge 1 commit intonginx:masterfrom
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When updating an existing key's string value in a shared dictionary with timeout and evict enabled, ngx_js_dict_alloc() could trigger ngx_js_dict_evict() if the zone was full. Since the node being updated was still in the expire tree, eviction could free it. The subsequent ngx_slab_free_locked() call in the update path then freed the already-freed string data, causing the "chunk is already free" alert followed by a segfault. The issue was more likely to occur when the zone fills to capacity and eviction is triggered during the update path. This closes nginx#1036 issue on Github.
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When updating an existing key's string value in a shared dictionary with timeout and evict enabled, ngx_js_dict_alloc() could trigger ngx_js_dict_evict() if the zone was full. Since the node being updated was still in the expire tree, eviction could free it. The subsequent ngx_slab_free_locked() call in the update path then freed the already-freed string data, causing the "chunk is already free" alert followed by a segfault.
The issue was more likely to occur when the zone fills to capacity and eviction is triggered during the update path.
This closes #1036 issue on Github.