Messages in this thread | | | From | Beau Belgrave <> | Subject | [PATCH v3 0/4] tracing/user_events: Use non-RCU context for enabler writes | Date | Fri, 19 May 2023 16:07:37 -0700 |
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Currently when events are enabled/disabled a top level mm enumeration is done in a non-RCU context, however, the enablers are still in a RCU-context. Each enabler is updated via user_event_enabler_write() which uses pin_user_pages_remote(). This function can reschedule and should not be used from a RCU-context, which this series addresses.
There was also feedback given that some of the code was confusing and needed further comments and field renames, especially for links. I think having this feedback will help others contribute to this code easier, so I am grouping this into a single series to address this together.
NOTE: Series is based on the for-next branch of the following tree: git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
Change history
V3: Use Linus's patches to more completely solve this issue.
Added comments and renamed fields as suggested by Linus to ensure easier reasoning over the code for everyone.
V2: Remove break statement that prevents more than 1 enabler in MM for same event (rare, but possible).
Beau Belgrave (2): tracing/user_events: Rename link fields for clarity tracing/user_events: Document user_event_mm one-shot list usage
Linus Torvalds (2): tracing/user_events: Split up mm alloc and attach tracing/user_events: Remove RCU lock while pinning pages
include/linux/user_events.h | 3 +- kernel/trace/trace_events_user.c | 97 +++++++++++++++++++++----------- 2 files changed, 67 insertions(+), 33 deletions(-)
base-commit: 3862f86c1529fa0016de6344eb974877b4cd3838 -- 2.25.1
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