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ubc_msync have a bug

the conflict between ubcmsync of kext and msync of application, my company has implemented a file system similar to NFS, which is implemented by kext. Now we use the rwtest03 case in the modified LTP program to test the consistency of the file system. We find that the data inconsistency is caused by msync function call in the application layer and UBCmsync in kext call conflict, suspected VFS layer processing problem. The test scenario is as follows: 20 processes open the same file, the file size is 12.8 million bytes, MMAP maps the whole file, lock random file range, lock range before memcopy, msync whole file, umap file, read file and write content comparison, close file. The above procedure is called circularly. During the calling process, in the kext file system call occasionally ubcmsync with flag of pull all sync invalidate is the call to the entire file in vnopgetattr, which we must use. It is found that the pageout caused by mmap of application layer is input to our file system. Occasionally, a page of data is old data or bad data, such as all zeros. Occasionally, it can cause double fault in the pageout. We strongly doubt the ubcmsync of Mac OS X and application layer call msync system call caused by the problem, whether there is an expert to answer. thank you.mac os x 10.14.0
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by chenhuaiyu.
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The problem of log not updating

In kext I use kprintf outputs log information for debugging. The running environment is product version: 10.14 buildversion: 18a391. After the system has been running for a period of time, I found that the log content is no longer updated by entering the command: log show -- predict 'process = = kernel " in the terminal. What's the reason? How to solve it! thank you!
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The problem of log not updating

In kext I use kprintf outputs log information for debugging. The running environment is product version: 10.14 buildversion: 18a391. After the system has been running for a period of time, I found that the log content is no longer updated by entering the command: log show -- predict 'process = = kernel " in the terminal. What's the reason? How to solve it! thank you!
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How to detect the memory leak of a file system kext and the methods and steps of remote debugging kext

HI: I am developing a file system driver. On Mac OS X, the machine will be stuck during operation, and "zonemapexhaustion: Zone map size 765046784, capacity 805306368 [jetsam limit 95%]" will appear in the syslog prompt, I suspect that it is caused by a memory leak in kext. Someone knows how to detect a memory leak of a file system kext and the methods and steps of remotely adjusting this kext? Do you have any information? thank you
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kauth_ cred_ grnam2guid The following symbols are unresolved for this kext

I'm writing a file system driver (kext) using "kauth cred grnam2guid" function, but the following "symbols are unresolved for this kext" when kextload, and cannot be found kauth  cred grnam2guid symbol, kextfind this function symbol in the private.kext Inside. Is there a way to solve this problem?
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10.14.4(18E226) how can i print pointers addr in my kext

hi:i am developping a kext,now i can not printf pointer addr to log,show <private> in log,my os is 10.14.4(18E226),i has always csrutil disable and nvram boot-args="-show_pointers",how can i do now!
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