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Add missing M_NOWAIT flag
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Authored by rstone on Oct 23 2019, 4:21 PM.

Details

Summary

The LinuxKPI linux_dma code calls PCTRIE_INSERT with a
mutex held, but does not set M_NOWAIT when allocating
nodes, leading to a potential panic. All of this code
can handle an allocation failure here, so prefer an
allocation failure to sleeping on memory.

Also fix a related case where NOWAIT/WAITOK was not
specified. In this case it's not clear whether sleeping
is allowed so be conservative and assume not. There are
a lot of other paths in this code that can fail due to
a lack of memory anyway.

Sponsored by: Dell EMC Isilon
MFC After: 1 week

Diff Detail

Repository
rS FreeBSD src repository
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Automatic diff as part of commit; lint not applicable.
Unit
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Event Timeline

rstone created this revision.Oct 23 2019, 4:21 PM
imp accepted this revision.Oct 23 2019, 4:36 PM

This looks correct.
I agree with the IRC comment about a kassert in uma_zalloc for the flags, but that's not needed here.

This revision is now accepted and ready to land.Oct 23 2019, 4:36 PM
This revision was automatically updated to reflect the committed changes.