Page MenuHomeFreeBSD
Differential D27522

fd: make serialization in fdescfree_fds conditional on hold count
ClosedPublic
Actions

Authored by mjg on Dec 9 2020, 2:44 PM.
Tags
None
Referenced Files
Unknown Object (File)
Thu, May 2, 3:15 AM
Unknown Object (File)
Tue, Apr 23, 9:47 AM
Unknown Object (File)
Feb 15 2024, 9:59 AM
Unknown Object (File)
Dec 10 2023, 9:01 AM
Unknown Object (File)
Dec 9 2023, 6:13 PM
Unknown Object (File)
Dec 9 2023, 2:48 PM
Unknown Object (File)
Dec 9 2023, 2:43 PM
Unknown Object (File)
Nov 19 2023, 1:17 AM
View All 30 Files
Subscribers
imp

Details

Reviewers
kib
markj
Commits
rS368516: fd: make serialization in fdescfree_fds conditional on hold count
Summary

p_fd nullification in fdescfree serializes against new threads transitioning the count 1 -> 2, meaning that fdescfree_fds observing the count of 1 can safely assume there is nobody else using the table. Losing the race and observing > 1 is harmless.

Diff Detail

Repository
rS FreeBSD src repository - subversion
Lint
Lint Not Applicable
Unit
Tests Not Applicable

Event Timeline

mjg requested review of this revision.Dec 9 2020, 2:44 PM
mjg created this revision.
markj accepted this revision.Dec 10 2020, 2:57 PM
markj added inline comments.
sys/kern/kern_descrip.c
2470 ↗(On Diff #80477)

It would be worth adding a sentence explaining why we know that fd_holdcnt can't increase at this point.

This revision is now accepted and ready to land.Dec 10 2020, 2:57 PM
Closed by commit rS368516: fd: make serialization in fdescfree_fds conditional on hold count (authored by mjg). · Explain WhyDec 10 2020, 5:17 PM
This revision was automatically updated to reflect the committed changes.
mjg added a commit: rS368516: fd: make serialization in fdescfree_fds conditional on hold count.
Herald added a subscriber: imp. · View Herald TranscriptDec 10 2020, 5:17 PM

Revision Contents
Changeset List

PathSize
head/
sys/
kern/
10 lines

Diff 80531

View Options

head/sys/kern/kern_descrip.c

Loading...