Messages in this thread | | | From | Marco Elver <> | Date | Thu, 22 Apr 2021 16:10:37 +0200 | Subject | Re: [PATCH 1/2] mm/kasan: avoid duplicate KASAN issues from reporting |
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On Thu, 22 Apr 2021 at 11:17, Maninder Singh <maninder1.s@samsung.com> wrote: > > when KASAN multishot is ON and some buggy code hits same code path > of KASAN issue repetetively, it can flood logs on console. > > Check for allocaton, free and backtrace path at time of KASAN error, > if these are same then it is duplicate error and avoid these prints > from KASAN.
On a more fundamental level, I think this sort of filtering is the wrong solution to your problem. One reason why it's good that multishot is off by default is, because _every_ KASAN report is critical and can destabilize the system. Therefore, any report after the first one might be completely bogus, because the system is in a potentially bad state and its behaviour might be completely random.
The correct solution is to not leave the system running, fix the first bug found, continue; rinse and repeat. Therefore, this patch adds a lot of code for little benefit.
The much simpler solution that will likely yield a similar result is to simply define an upper bound on the number of reports if multishot is on. Because if I've seen 1000 reports, I already know the system is completely trashed and whatever else it's reporting might just be random.
Thanks, -- Marco
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