Re: [PATCH] Revert "seqlock: lockdep assert non-preemptibility on seqcount_t write"

[Valdis Klētnieks]

On Mon, 10 Aug 2020 07:10:32 -0700, Guenter Roeck said:
> > 	ERROR: modpost: "__bad_udelay" [drivers/net/ethernet/aquantia/atlantic/atlantic.ko] undefined!
> > 
>
> I don't think that is new. If anything, it is surprising that builds don't fail more
> widely because of it. AFAICS it was introduced back in 2018 (a hot 50-ms delay loop
> really isn't such a good idea).

Well...it wasn't broken in next-20200720.  A bit of poking with nm,
and building hw_atl/hw_atl_b0.s, it looks like the culprit is this commit:

commit 8dcf2ad39fdb2d183b7bd4307c837713e3150b9a
Author: Mark Starovoytov <mstarovoitov@xxxxxxxxxxx>
Date:   Mon Jul 20 21:32:44 2020 +0300

    net: atlantic: add hwmon getter for MAC temperature

specifically this chunk around line 1634 of hw_atl/hw_atl_b0.c:


+       err = readx_poll_timeout_atomic(hw_atl_b0_ts_ready_and_latch_high_get,
+                                       self, val, val == 1, 10000U, 500000U);

And doing a 'git revert' makes the build work....