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libelf_elfsize() takes textalign and dataalign from the section headers, which only the ET_REL path walks. An ET_DYN object is sized from its program headers instead, so both fields stay at zero, and the allocation a few lines later asks for that alignment: loadinfo->textalloc = lib_memalign(loadinfo->textalign, ...); Zero is not a valid alignment, and every path that receives it divides by it. mm_memalign() accepts zero as a power of two, because 0 & -0 is 0, then takes the "alignment <= MM_ALIGN" branch and evaluates "((uintptr_t)ptr) % alignment" in a DEBUGASSERT. With CONFIG_MM_HEAP_MEMPOOL and a pool that fits the request the object never reaches that branch and gets ALIGN_UP(blk, 0) instead, which is ((blk - 1) / 0) * 0. On Cortex-M this is usually invisible: UDIV returns zero for a division by zero unless CCR.DIV_0_TRP is set, which NuttX does not set, so the assertion compares zero against zero and passes. It is a SIGFPE on the simulator, and the mempool path returns a null pointer wherever the division yields zero, which the loader reports as -ENOMEM. Ask for a natural word when the program headers gave nothing. p_align is the linker's page granularity, not a section requirement, so honouring it would cost a page per module for no gain, and the sections of a shared object need no more than a word. Built for mps3-an547:picostest, which is CONFIG_ELF with CONFIG_PIC. Runtime evidence on hardware follows. Assisted-by: Claude Opus 5 (1M context) <noreply@anthropic.com> Signed-off-by: Marco Casaroli <marco.casaroli@gmail.com> |
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