Re: [PATCH 1/2] kmemleak: drop (age <increasing>) from leak record

From: Catalin Marinas
Date: Sat Nov 18 2023 - 12:35:29 EST


On Thu, Nov 16, 2023 at 03:43:17PM -0700, Jim Cromie wrote:
> Displaying age is pretty, but counter-productive; it changes with
> current-time, so it surrenders idempotency of the output, which breaks
> simple hash-based cataloging of the records by the user.
>
> The trouble: sequential reads, wo new leaks, get new results:
>
> :#> sum /sys/kernel/debug/kmemleak
> 53439 74 /sys/kernel/debug/kmemleak
> :#> sum /sys/kernel/debug/kmemleak
> 59066 74 /sys/kernel/debug/kmemleak
>
> and age is why (nothing else changes):
>
> :#> grep -v age /sys/kernel/debug/kmemleak | sum
> 58894 67
> :#> grep -v age /sys/kernel/debug/kmemleak | sum
> 58894 67
>
> Since jiffies is already printed in the "comm" line, age adds nothing.
>
> Notably, syzkaller reads kmemleak only for "unreferenced object", and
> won't care about this reform of age-ism. A few moribund github repos
> mention it, but don't compile.
>
> Signed-off-by: Jim Cromie <jim.cromie@xxxxxxxxx>

Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>