Re: kern/51254 (uvm assertion "!topdown || hint <= orig_hint" failed)

[Rin Okuyama <rokuyama.rk%gmail.com@localhost>]

The following reply was made to PR kern/51254; it has been noted by GNATS.

From: Rin Okuyama <rokuyama.rk%gmail.com@localhost>
To: "gnats-bugs%NetBSD.org@localhost" <gnats-bugs%NetBSD.org@localhost>
Cc: Taylor R Campbell <riastradh%NetBSD.org@localhost>,
 Martin Husemann <martin%NetBSD.org@localhost>, uwe%NetBSD.org@localhost
Subject: Re: kern/51254 (uvm assertion "!topdown || hint <= orig_hint" failed)
Date: Mon, 6 Jun 2022 16:27:08 +0900

 Now, I'm testing this patch:
 
 https://gist.github.com/rokuyama/62f4b8b3eb486109629358df9ca31e62
 
 Fix for kern/54395 was insufficient. It addressed a case where hint
 is modified in uvm_map_space_avail() due to (1) alignment constraint.
 
 However, hint can also be modified in that function due to
 (2) PMAP_PREFER and (3) color constraint, and these cases also
 result in KASSERT failures similar to one reported in kern/54395.
 
 This PR, kern/51254 is case (2) itself.
 
 In this patch, in addition to (1), (2) and (3) are taking into
 account; hint is adjusted at the beginning of uvm_map_findspace()
 according to these requirements. Also, I've added check for
 (flags & UVM_FLAG_FIXED) == 0 before hint is modified.
 
 With this patch, aarch64eb machine (ncolors=4) successfully
 completes full ATF run without regressions.
 
 Now, I'm carrying out stress tests on two sh3 machines with
 DIAGNOSTIC kernel; one for building pkgsrc's and one for full
 ATF run. Their uptime exceeds 4 hours without problems.
 
 Thanks,
 rin