PATCH: Re: LOCKDEP customizable numbers upper limit

[hooanon05g@gmail.com]

Tetsuo Handa:
> Please submit a patch that avoids only BUILD_BUG_ON().

Here it is.

J. R. Okajima

----------------------------------------
commit 43e103e1a5975c61334811d16e207e6d0ac57b77
Author: J. R. Okajima <hooanon05g@gmail.com>
Date:   Sat May 15 03:17:10 2021 +0900

    LOCKDEP: upper limit LOCKDEP_CHAINS_BITS
    
    CONFIG_LOCKDEP_CHAINS_BITS value decides the size of chain_hlocks[] in
    kernel/locking/lockdep.c, and it is checked by add_chain_cache() with
            BUILD_BUG_ON((1UL << 24) <= ARRAY_SIZE(chain_hlocks));
    This patch is just to silence BUILD_BUG_ON().
    
    See-also: https://marc.info/?l=linux-kernel&m=162091320503900&w=2
    Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 678c13967580e..999ed5aa6bcee 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1390,7 +1390,7 @@ config LOCKDEP_BITS
 config LOCKDEP_CHAINS_BITS
 	int "Bitsize for MAX_LOCKDEP_CHAINS"
 	depends on LOCKDEP && !LOCKDEP_SMALL
-	range 10 30
+	range 10 21
 	default 16
 	help
 	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.