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authorHaojie Li <lihaojie@kylinos.cn>2026-08-25 18:08:45 +0800
committerChun-Kuang Hu <chunkuang.hu@kernel.org>2026-09-28 23:20:55 +0000
commitbce7698e2e6565bb765bd0522337f29f5f312624 (patch)
tree0b735b7b4a27369cb4d75d9431b3ee59ce7e5bcc /tools/lib/perf/TODO
downloadlinux-stable-bce7698e2e6565bb765bd0522337f29f5f312624.tar.gz
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drm/mediatek: Add missing IS_ERR check for ovl_adaptor platform devicegrafted
platform_device_register_data() can fail and return an ERR_PTR, but the return value is used without checking, leading to an invalid pointer being stored in ddp_comp[].dev and passed to component_match_add() and mtk_ddp_comp_init(), which could result in a kernel crash. Add an IS_ERR() check to jump to the error handling path on failure. Fixes: 0d9eee9118b7 ("drm/mediatek: Add drm ovl_adaptor sub driver for MT8195") Cc: stable@vger.kernel.org Signed-off-by: Haojie Li <lihaojie@kylinos.cn> Reviewed-by: CK Hu <ck.hu@mediatek.com> Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20260825100845.438893-1-lihaojie@kylinos.cn/ Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
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+Future ABI changes
+==================
+
+This file collects items that require a libperf ABI bump. Each entry
+should describe the current limitation, the desired end state, and the
+scope of the change so that a future ABI revision can batch them
+together.
+
+1. Widen struct perf_cpu.cpu from int16_t to int
+ - Current limit: 32767 CPUs. No architecture exceeds this today
+ (x86_64 max is 8192, arm64 is 4096), but NR_CPUS limits keep
+ growing. perf clamps to INT16_MAX in set_max_cpu_num() as a
+ safety net.
+ - Code simplification: the int16_t forces defensive truncation
+ checks at every boundary where a wider CPU index (int from
+ sample->cpu, al->cpu, etc.) is narrowed into struct perf_cpu.
+ Without these checks, values > 32767 silently wrap to negative
+ numbers (two's complement), bypassing bounds validation.
+ Widening to int eliminates this entire class of silent
+ truncation bugs and removes the need for the INT16_MAX clamp
+ in set_max_cpu_num().
+ - Scope: struct perf_cpu is embedded everywhere — perf_cpu_map__cpu(),
+ perf_cpu_map__min(), perf_cpu_map__max(), perf_cpu_map__has(), the
+ for_each_cpu macros, and all internal callers. The perf_cpu_map
+ internal array (RC_CHK_ACCESS(map)->map[]) stores struct perf_cpu
+ directly. Widening changes the struct layout and every function
+ that returns or accepts struct perf_cpu by value.
+ - Migration: bump LIBPERF version in libperf.map, audit all
+ sizeof(struct perf_cpu) assumptions, update perf.data
+ serialization if needed.