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Diffstat (limited to 'results/classifier/deepseek-r1:32b/reasoning/runtime/1740219')
| -rw-r--r-- | results/classifier/deepseek-r1:32b/reasoning/runtime/1740219 | 34 |
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diff --git a/results/classifier/deepseek-r1:32b/reasoning/runtime/1740219 b/results/classifier/deepseek-r1:32b/reasoning/runtime/1740219 new file mode 100644 index 000000000..3a3f447f8 --- /dev/null +++ b/results/classifier/deepseek-r1:32b/reasoning/runtime/1740219 @@ -0,0 +1,34 @@ +<think> +Okay, so I'm looking at this bug report about QEMU's user emulation having a long startup time when using a static build. The problem is that after updating from version 2.8 to 2.11, running `qemu-arm` takes several seconds instead of milliseconds. The issue seems to be happening in the `init_guest_space()` function within `elfload.c`. + +From what I gather, the main points are: + +1. **Problem Description**: With QEMU 2.11 static build, starting an emulation (like running `/my/arm-chroot/bin/true`) takes about 3 seconds instead of 0.006s as before. This doesn't happen with dynamically linked builds or older static builds. + +2. **Cause Analysis**: + - The function `init_guest_space()` is trying to map two parts of the address space: `[base, base+guest_size]` and `[base + 0xffff0000, ...]`. + - In QEMU 2.11, the default `guest_size` was increased from 0xf7000000 to 0xffff0000. + - Static builds disable PIE (Position Independent Executable) and thus ASLR (Address Space Layout Randomization), which affects where memory is mapped. + +3. **Behavior**: + - With the larger `guest_size`, the initial `mmap(NULL, ...)` call tends to return a base that's too close to an already mapped area. + - Without ASLR in static builds, the text segment starts at 0x60000000. This leaves no space before it for the required mappings, causing QEMU to try many different bases (over 12000 times) until it finds a suitable one. + +4. **Potential Fixes**: + - The idea of first mapping a larger chunk and then munmapping parts to create the needed spaces was mentioned but might not support sparse address space. + - Another thought is checking `/proc/self/maps` for available ranges before attempting `mmap`. + +5. **Categories to Choose From**: instruction, syscall, runtime. + +Now, considering these points, I need to classify this bug into one of the three categories: instruction, syscall, or runtime. + +- **Instruction**: This would involve issues with specific CPU instructions causing problems. The report doesn't mention any incorrect instructions being executed, so probably not. + +- **Syscall**: Problems related to system calls. While `mmap` is a syscall involved here, the issue isn't that the syscalls are failing or behaving incorrectly per se, but more about how QEMU's algorithm interacts with the memory mapping behavior. + +- **Runtime**: Errors that occur during runtime operations, which seems fitting because the problem arises in how QEMU manages its address space at startup. The long delay is due to repeated `mmap` attempts as it searches for a suitable base address, which is a runtime operation issue. + +So, the bug isn't about incorrect instructions or syscalls failing but rather the runtime behavior of QEMU's memory management algorithm. +</think> + +runtime \ No newline at end of file |