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    SubjectRe: [PATCH] tracing/lockdep: turn lock->name into an array
    Date
    > 
    > * KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> wrote:
    >
    > > Hi
    > >
    > > > Impact: allow filtering by lock name / fix module tracing
    > > >
    > > > Currently, the "lock acquired" event is traced using a TRACE_EVENT.
    > > > But we can't use the char * type for the name without risking to
    > > > dereference a freed pointer. A lock name can come from a module
    > > > towards lockdep and it is risky to only store its address because we
    > > > defer its name printing.
    > >
    > > When released lockdep string table? I guess it only happend at
    > > module unloading. if so, we should consider to make delayed string
    > > table freeing at module unloading.
    > >
    > > My point is, module unloading is rare event. thus meking pointer
    > > safe mechanism widely avoid string copy.
    > >
    > > IOW, if not, ringbuffer is filled tons string. it kill the merit
    > > of binary buffer and current design.
    >
    > We could zap all pending trace entries on module unload (it is a
    > rare operation). That would indeed make a whole category of
    > symbol-alike string pointers safe to be passed by value.

    Oh, it seems very good idea!





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