Differential D25541

iflib: initialize netmap with the correct number of descriptors
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Authored by vmaffione on Jul 1 2020, 7:24 PM.

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Details

Reviewers

gallatin
• hselasky
shurd

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Commits

rS364085: MFC r363378
rS363378: iflib: initialize netmap with the correct number of descriptors

Summary

In case the network device has a RX or TX control queue, the correct number of TX/RX descriptors is contained
in the second entry of the isc_ntxd (or isc_nrxd) array, rather than in the first entry.
This case is correctly handled by iflib_device_register() and iflib_pseudo_register(), but not by
iflib_netmap_attach(). If the first entry is larger than the second, this can result in a panic.
This change fixes the bug by introducing two helper functions that also lead to some code simplification.

PR 247647 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=247647

Test Plan

Tested on vmx0 interface on QEMU/KVM. After the fix, iflib does not panic anymore.

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Repository

rS FreeBSD src repository - subversion

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Event Timeline

vmaffione created this revision.Jul 1 2020, 7:24 PM

Herald added a reviewer: shurd. · View Herald TranscriptJul 1 2020, 7:24 PM

Herald added 1 blocking reviewer(s): iflib. · View Herald Transcript

Herald added subscribers: melifaro, ae, imp. · View Herald Transcript

vmaffione requested review of this revision.Jul 1 2020, 7:24 PM

Harbormaster completed remote builds in B32101: Diff 73988.Jul 1 2020, 7:24 PM

vmaffione edited the summary of this revision. (Show Details)Jul 1 2020, 7:36 PM

The PR reporter has tested the patch and confirmed that the panic has been fixed. See https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=247647

This revision was not accepted when it landed; it landed in state Needs Review.Jul 20 2020, 9:09 PM

Closed by commit rS363378: iflib: initialize netmap with the correct number of descriptors (authored by vmaffione). · Explain Why

This revision was automatically updated to reflect the committed changes.

vmaffione added a commit: rS363378: iflib: initialize netmap with the correct number of descriptors.

vmaffione added a commit: rS364085: MFC r363378.Aug 10 2020, 5:53 PM

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Path

Size

head/

sys/

net/

60 lines

Diff 74720

head/sys/net/iflib.c

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