Add kpreempt_disable/enable around CPU_SEQID uses to fix kernel BUG warnings #6239
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numinit
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behlendorf
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module/zfs/dmu_object.c
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| /* | ||
| * Pick the current CPU. We need to disable preemption to ensure that | ||
| * we don't get interrupted (and pick the wrong CPU). | ||
| */ |
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In this case it isn't really about picking the wrong cpu, it's about using the current cpu as a hint to minimize lock contention. The code is written is such a way that it's safe for this function to be rescheduled at any time to a different cpu. I'd suggest dropping the comment here to avoid any confusion.
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In zfs/dmu_object and icp/core/kcf_sched, the CPU_SEQID macro should be surrounded by `kpreempt_disable` and `kpreempt_enable` calls to avoid a Linux kernel BUG warning. Signed-off-by: Morgan Jones <me@numin.it>
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@numinit were you able to verify this resolved the warnings. |
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Yes, this resolves the warnings for me. Removing the testing WIP label. |
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@numinit great, thanks for the confirmation. Will merge. |
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Description
In
zfs/dmu_objectandicp/core/kcf_sched, theCPU_SEQIDmacro should be surrounded bykpreempt_disableandkpreempt_enablecalls to avoid a Linux kernel BUG warning.Motivation and Context
Remediating frequent (but mostly harmless) Linux kernel BUG warnings during use of the ZFS 0.7 release candidate (see #6232)
How Has This Been Tested?
Compiled and installed the module. The system affected by #6232 no longer gets these BUG warnings in its dmesg.
Types of changes
Checklist:
Signed-off-by.