| Summary: | Cast float->int leads to segmentation fault in compile-time | ||
|---|---|---|---|
| Product: | Beignet | Reporter: | pavelko95 |
| Component: | Beignet | Assignee: | ruiling <ruiling.song> |
| Status: | RESOLVED MOVED | QA Contact: | |
| Severity: | normal | ||
| Priority: | medium | ||
| Version: | unspecified | ||
| Hardware: | x86-64 (AMD64) | ||
| OS: | Linux (All) | ||
| Whiteboard: | |||
| i915 platform: | i915 features: | ||
Assert when visit uninitialized pointer. Do you have other idea? (In reply to rongyang from comment #1) > Assert when visit uninitialized pointer. Do you have other idea? There is something strange: float a = 10.; float *stack[10] = {&a}; // sigfault float a = 10.; float *stack[10] = {&a, &a, &a, &a}; // sigfault float a = 10.; float *stack[10] = {&a, &a, &a, &a, &a}; // ok float *stack[2]; // sigfault float *stack[1]; // ok float a; float *stack[2] = {&a}; // ok I take a quick look. it is related to storing pointers to private array. Gen hardware does not support accessing random address. it only support memory read/write through a surface index. so when declaring a private array of pointers, we need to analyze where it is storing pointers into the pointer array. the bug is related to analyzing the pointer's surface index in llvm_gen_backend.cpp. I will take a further look to see how to fix it. I am sorry for so late fix because of working on ocl 2.0 development. I finally make some time to fix it: https://lists.freedesktop.org/archives/beignet/2016-July/007710.html https://lists.freedesktop.org/archives/beignet/2016-July/007711.html -- GitLab Migration Automatic Message -- This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity. You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/beignet/beignet/issues/17. |
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Ok, I spent a lot of time to isolate the problem as much as possible. All components (loop, condition, casting and modification of `i`) are required to reproduce the bug. Steps to Reproduce: 1) Write kernel: kernel void evaluate(void) { float *stack[10]; int i = 1; while (i) if ((int)(*stack[i])) --i; } 2) Try to build the program Actual Results: A segmentation fault occurs when trying to build program (`clBuildProgram(program, 0, NULL, NULL, NULL, NULL)`) Expected Results: The program should be successfully compiled. Or, at least, should not sigfault. Additional Information: `dmesg` after couple runs: [72307.125321] ocl-bf[9586]: segfault at 7ff300000018 ip 00007ff3d25fac10 sp 00007fff77f05dd8 error 4 in libgbe.so[7ff3d21f0000+1a3c000] [72308.493759] ocl-bf[9601]: segfault at 0 ip 00007f7ea7850b14 sp 00007ffdb72e4fc0 error 4 in libgbe.so[7f7ea7442000+1a3c000] [72326.034834] ocl-bf[9635]: segfault at 7ffc101d2ff8 ip 00007fa682413ac4 sp 00007ffc101d3000 error 6 in libgbe.so[7fa682005000+1a3c000] OS: Arch linux, 4.2.5-1, x86_64 Device: Intel HD 4400/Haswell i5 Beignet: 1.1.1-4 (AUR: https://aur.archlinux.org/packages/beignet/)