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LinuxKPI: avoid userret: Returning with with pinned thread

Description

LinuxKPI: avoid userret: Returning with with pinned thread

Some code manually calls local_bh_disable() and spin_lock() but
then calls spin_unlock_bh() (or vice versa).
Our code then calls local_bh_disable() again from spin_lock()
which means we have the thread pin count increased twice and that
means we get out of synch and are still pinned when returning to
user space.

Avoid this by adding the explicit local_bh_{enable,disable}() to
the spin_[un]lock_bh() versions.

Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Reviewed by: hselasky
Differential Revision: https://reviews.freebsd.org/D30711

Details

Provenance
bzAuthored on Jun 9 2021, 6:53 PM
Reviewer
hselasky
Differential Revision
D30711: LinuxKPI: avoid userret: Returning with with pinned thread
Parents
rGedfcdffefc16: LinuxKPI: fix sg_pcopy_from_buffer()
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