Differential D31921

Fix LOR
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Authored by tuexen on Sep 12 2021, 5:37 PM.

Details

Reviewers

markj
tuexen

Group Reviewers

transport

Commits

rG91ef9a745e10: sctp: avoid LOR
rG29545986bdf6: sctp: avoid LOR

Summary

Don't try to lock the inp-info lock while holding an stcb lock (and don't lock twice...)

Diff Detail

Repository

rG FreeBSD src repository

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Lint Not Applicable

Unit

Tests Not Applicable

Event Timeline

tuexen created this revision.Sep 12 2021, 5:37 PM

Herald added a reviewer: transport. · View Herald TranscriptSep 12 2021, 5:37 PM

Herald added a subscriber: melifaro. · View Herald Transcript

tuexen requested review of this revision.Sep 12 2021, 5:37 PM

How was it getting locked twice?

In D31921#720187, @markj wrote:

How was it getting locked twice?

Because

SCTP_INP_INFO_RLOCK();
new_vtag = sctp_select_a_tag(stcb->sctp_ep, stcb->sctp_ep->sctp_lport, stcb->rport, 1);
SCTP_INP_INFO_RLOCK();

should have been

SCTP_INP_INFO_RLOCK();
new_vtag = sctp_select_a_tag(stcb->sctp_ep, stcb->sctp_ep->sctp_lport, stcb->rport, 1);
SCTP_INP_INFO_RUNLOCK();

(the difference is in the last line).

tuexen accepted this revision.Sep 12 2021, 7:10 PM

This revision is now accepted and ready to land.Sep 12 2021, 7:10 PM

Closed by commit rG29545986bdf6: sctp: avoid LOR (authored by tuexen). · Explain WhySep 12 2021, 7:13 PM

This revision was automatically updated to reflect the committed changes.

tuexen added a commit: rG29545986bdf6: sctp: avoid LOR.

In D31921#720190, @tuexen wrote:
In D31921#720187, @markj wrote:

How was it getting locked twice?

Because
SCTP_INP_INFO_RLOCK();
new_vtag = sctp_select_a_tag(stcb->sctp_ep, stcb->sctp_ep->sctp_lport, stcb->rport, 1);
SCTP_INP_INFO_RLOCK();
should have been
SCTP_INP_INFO_RLOCK();
new_vtag = sctp_select_a_tag(stcb->sctp_ep, stcb->sctp_ep->sctp_lport, stcb->rport, 1);
SCTP_INP_INFO_RUNLOCK();
(the difference is in the last line).