Differential D30400

ktrace: fix a race between writes and close
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Authored by kib on May 22 2021, 1:40 PM.

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rGfc369a353b5b: ktrace: fix a race between writes and close

Summary

It was possible that termination of ktrace session occured during some record write, in which case write occured after the close of the vnode. Use ktr_io_params refcounting to avoid this situation, by taking the reference on the structure instead of vnode.

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rG FreeBSD src repository

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kib requested review of this revision.May 22 2021, 1:40 PM

kib created this revision.

markj accepted this revision.May 22 2021, 3:56 PM

markj added inline comments.

sys/kern/kern_ktrace.c
1360	So we disable tracing if the file is closed and re-opened, i.e., ABA-like race. I think that is ok.

This revision is now accepted and ready to land.May 22 2021, 3:56 PM

kib marked an inline comment as done.May 22 2021, 7:34 PM

kib added inline comments.

sys/kern/kern_ktrace.c
1360	Yes it is same as before ktr_io_params introduction, and I decided to keep it that way from that time.

Closed by commit rGfc369a353b5b: ktrace: fix a race between writes and close (authored by kib). · Explain WhyMay 22 2021, 8:14 PM

This revision was automatically updated to reflect the committed changes.

kib marked an inline comment as done.

kib added a commit: rGfc369a353b5b: ktrace: fix a race between writes and close.

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sys/

kern/

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Diff 89660

sys/kern/kern_ktrace.c

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