fix(mm): add VmIo retry logic for lazy allocation#94
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sunhaosheng wants to merge 4 commits intoStarry-OS:mainfrom
Closed
fix(mm): add VmIo retry logic for lazy allocation#94sunhaosheng wants to merge 4 commits intoStarry-OS:mainfrom
sunhaosheng wants to merge 4 commits intoStarry-OS:mainfrom
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When kernel reads/writes user memory that is lazily allocated but not yet faulted in, user_copy (assembly function) uses exception table to handle page faults and returns failure instead of triggering the kernel's page fault handler. Fix: Add retry logic in VmIo read/write: 1. First attempt the read/write via user_copy 2. If failed, calculate the faulting address from failure offset 3. Call populate_area() to ensure pages are allocated 4. Retry the read/write operation Also changed ELF segment mapping to use populate=true for immediate allocation to avoid retry overhead during early execution.
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VmIo Lazy Allocation Failure
Files:
core/src/mm.rsapi/src/io.rsapi/src/mm.rsBug Description:
When the kernel tried to read/write user memory that was lazily allocated but not yet faulted in, the operation would fail with
AccessDeniedinstead of triggering page fault handling.Fix:
Added retry logic with page population:
populate_areato ensure the pages are allocated