RFC uprobes: kill uprobes_srcu/uprobe_srcu_id
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b4 am [email protected]Versions newest first
- v1 RFC Latest6 patches 31 repliesIn review
Patches in v1 No applies recorded yet
| # | Subject and files | Size | Replies | Applied |
|---|---|---|---|---|
| 1/6 | uprobes: introduce find_active_uprobe()kernel/ | +19 | 0 replies | |
| 2/6 | uprobes: introduce is_swbp_at_addr_fast()kernel/ | +23 | 7 replies | |
| 3/6 | uprobes: teach find_active_uprobe() to provide the "is_swbp" infokernel/ | +17 | 0 replies | |
| 4/6 | uprobes: change register_for_each_vma() to take mm->mmap_sem for writingkernel/ | +4 | 0 replies | |
| 5/6 | uprobes: teach handle_swbp() to rely on "is_swbp" rather than uprobes_srcukernel/ | +15 | 0 replies | |
| 6/6 | uprobes: kill uprobes_srcu/uprobe_srcu_idinclude/ kernel/ | +3 | 0 replies |
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Cover letter [RFC 0/6] uprobes: kill uprobes_srcu/uprobe_srcu_id
Hello.
Not for inclusion yet, only for the early review.
I didn't even try to test these changes, and I am not expert in this area. And even _if_ this code is correct, I need to re-split these changes anyway, update the changelogs, etc.
Questions:
- does it make sense?
- can it work or I missed something "in general" ?
Why:
- It would be nice to remove a member from task_struct.
- Afaics, the usage of uprobes_srcu does not look right, at least in theory, see 6/6.
The comment above delete_uprobe() says:
The current unregistering thread waits till all other threads have hit a breakpoint, to acquire the uprobes_treelock before the uprobe is removed from the rbtree.
but synchronize_srcu() can only help if a thread which have hit the breakpoint has already called srcu_read_lock(). It can't synchronize with read_lock "in future", and there is a small window.
We could probably add another synchronize_sched() before synchronize_srcu(), but this doesn't look very nice and
- I am not sure yet, but perhaps with these changes we can also kill mm->uprobes_state.count.
Any review is very much appreciated.
Oleg.
include/linux/sched.h | 1 - kernel/events/uprobes.c | 117 ++++++++++++++++++++++++++++++----------------- 2 files changed, 75 insertions(+), 43 deletions(-)
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