fix: inherit heap on fork and reset set_child_tid on execve
#93
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Bug 1 - Fork not inheriting heap pointers: After fork, child's heap_bottom/heap_top were reset to USER_HEAP_BASE instead of inheriting parent's heap state, causing brk() to fail. Fix: Copy heap pointers from parent to child in fork path. Bug 2 - set_child_tid/clear_child_tid NULL pointer issues: When CLONE_CHILD_SETTID or CLONE_CHILD_CLEARTID flags were set but child_tid was NULL, kernel would access invalid memory. Fix: Check address is non-NULL before processing, pass as usize, write using aspace.write() in child's context. Bug 3 - execve not clearing clear_child_tid: After execve, clear_child_tid from old address space remained set, causing invalid memory access on process exit. Fix: Clear clear_child_tid after execve.
guoweikang
reviewed
Dec 19, 2025
guoweikang
reviewed
Dec 19, 2025
guoweikang
approved these changes
Dec 22, 2025
AsakuraMizu
changed the title
set_child_tid on execve
guoweikang
added a commit
to kylin-x-kernel/StarryOS
that referenced
this pull request
Dec 23, 2025
fix: inherit heap on fork and reset `set_child_tid` on execve (Starry-OS#93)
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
4 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
File:
api/src/syscall/task/execve.rsBug Description:
After
execve, theclear_child_tidaddress from the old address space remained set. When the process eventually exited, it would try to write to an invalid address.Fix:
Clear
clear_child_tidafterexecve:File:
api/src/syscall/task/clone.rsBug Description:
After
fork, the child process'sheap_bottomandheap_topwere initialized toUSER_HEAP_BASEinstead of inheriting the parent's heap state. This caused the child'sbrkcalls to behave incorrectly.Fix:
Added heap pointer inheritance in the fork path: