Messages in this thread | | | Date | Mon, 21 Oct 2019 14:42:14 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 1/3] watchdog/softlockup: Preserve original timestamp when touching watchdog externally |
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On Mon, Aug 19, 2019 at 12:47:30PM +0200, Petr Mladek wrote: > Some bug report included the same softlockups in flush_tlb_kernel_range() > in regular intervals. Unfortunately was not clear if there was a progress > or not. > > The situation can be simulated with a simply busy loop: > > while (true) > cpu_relax(); > > The softlockup detector produces: > > [ 168.277520] watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [cat:4865] > [ 196.277604] watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [cat:4865] > [ 236.277522] watchdog: BUG: soft lockup - CPU#1 stuck for 23s! [cat:4865] > > One would expect only one softlockup report or several reports with > an increased duration.
Let's just say our expectations differ.
> The result is that each softlockup is reported only once unless > another process get scheduled: > > [ 320.248948] watchdog: BUG: soft lockup - CPU#2 stuck for 26s! [cat:4916]
Which would greatly confuse me; as the above would have me think the situation got resolved (no more lockups reported) even though it is still very much stuck there.
IOW, I don't see how this makes anything better. You're removing information.
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