debugobjects,locking: Annotate debug_object_fill_pool() wait type violation

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There is an explicit wait-type violation in debug_object_fill_pool()
for PREEMPT_RT=n kernels which allows them to more easily fill the
object pool and reduce the chance of allocation failures.

Lockdep's wait-type checks are designed to check the PREEMPT_RT
locking rules even for PREEMPT_RT=n kernels and object to this, so
create a lockdep annotation to allow this to stand.

Specifically, create a 'lock' type that overrides the inner wait-type
while it is held -- allowing one to temporarily raise it, such that
the violation is hidden.

Reported-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: Qi Zheng <zhengqi.arch@bytedance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Qi Zheng <zhengqi.arch@bytedance.com>
Link: https://lkml.kernel.org/r/20230429100614.GA1489784@hirez.programming.kicks-ass.net

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This commit is contained in:

Peter Zijlstra 2023-04-25 17:03:13 +02:00

parent 0af462f19e

commit 0cce06ba85

4 changed files with 49 additions and 9 deletions

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14

include/linux/lockdep.h

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1

include/linux/lockdep_types.h

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28

kernel/locking/lockdep.c

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15

lib/debugobjects.c

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