From e873c74132f0c5f1452816cd9bb26208f0bba1e1 Mon Sep 17 00:00:00 2001 From: Shivank Garg Date: Sat, 22 Aug 2026 19:22:05 +0000 Subject: dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() When dma_device_put() drops the last reference on chan->device->ref, dma_device_release() runs and may free the dma_device along with its channels. dma_chan_put() then still reads chan->device->owner via dma_chan_to_owner() for the trailing module_put(). KASAN catches it: slab-use-after-free in dma_chan_put+0x3e6/0x4c0 Read of size 8 by task insmod/6319 Freed by task 6319: kfree+0x225/0x470 dma_chan_put+0x395/0x4c0 dmaengine_put+0xf8/0x160 Cache the module owner in dma_chan_put() before the put so the trailing module_put() does not need chan->device. Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct") Suggested-by: Sashiko Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul --- tools/lib/perf/TODO | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100644 tools/lib/perf/TODO (limited to 'tools/lib/perf/TODO') diff --git a/tools/lib/perf/TODO b/tools/lib/perf/TODO new file mode 100644 index 000000000..e17972869 --- /dev/null +++ b/tools/lib/perf/TODO @@ -0,0 +1,30 @@ +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. -- cgit v1.3.1