Messages in this thread | | | Date | Tue, 16 Jul 2013 18:38:04 +0200 | From | Oleg Nesterov <> | Subject | Re: [RFC][PATCH 0/4] tracing/kprobes/uprobes: Fix race between opening probe event files and deleting probe |
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On 07/15, Oleg Nesterov wrote: > > So. As Masami pointed out, this is not enough. Probably we can add more > hacks, but I'd like to discuss the alternative approach. > > Note also that this ref count has the unfortunate property, if someone > keeps the file opened we can't remove an event.
And please correct me, but afaics there are similar problems with rmdir instances/xxx.
> What this patch does: > > - add the new "topmost" rw_semaphore, file_sem.
probably unneeded...
> - trace_remove_event_call() takes this sem for writing and > cleares enable/id/format/filter->i_private > > - removes tracing_open_generic_file/tracing_release_generic_file, > we do not use file->f_private any longer > > - changes event_enable_read/event_enable_write to read > ftrace_event_file = i_private under read_lock(file_sem) and > abort if it is null. > > Question: why event_enable_write() needs trace_array_get() ?
probably it doesn't...
> Steven, Masami, do you think this can make any sense?
Oleg.
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