The patch titled
Subject: checkpatch: warn on usage of VM_BUG_ON() and other BUG variants
has been added to the -mm mm-nonmm-unstable branch. Its filename is
checkpatch-warn-on-usage-of-vm_bug_on-and-other-bug-variants.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/checkpatch-warn-on-usage-of-vm_bug_on-and-other-bug-variants.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: David Hildenbrand <david@xxxxxxxxxx>
Subject: checkpatch: warn on usage of VM_BUG_ON() and other BUG variants
Date: Tue, 20 Sep 2022 14:23:02 +0200
checkpatch does not point out that VM_BUG_ON() and friends should be
avoided, however, Linus notes:
VM_BUG_ON() has the exact same semantics as BUG_ON. It is literally
no different, the only difference is "we can make the code smaller
because these are less important". [1]
So let's warn on VM_BUG_ON() and other BUG variants as well. While at it,
make it clearer that the kernel really shouldn't be crashed.
As there are some subsystem BUG macros that actually don't end up crashing
the kernel -- for example, KVM_BUG_ON() -- exclude these manually.
[1] https://lore.kernel.org/r/CAHk-=wg40EAZofO16Eviaj7mfqDhZ2gVEbvfsMf6gYzspRjYvw@xxxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20220920122302.99195-4-david@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Andy Whitcroft <apw@xxxxxxxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: Dave Young <dyoung@xxxxxxxxxx>
Cc: David Laight <David.Laight@xxxxxxxxxx>
Cc: Dwaipayan Ray <dwaipayanray1@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Cc: Joe Perches <joe@xxxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Lukas Bulwahn <lukas.bulwahn@xxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/scripts/checkpatch.pl~checkpatch-warn-on-usage-of-vm_bug_on-and-other-bug-variants
+++ a/scripts/checkpatch.pl
@@ -4745,12 +4745,12 @@ sub process {
}
}
-# avoid BUG() or BUG_ON()
- if ($line =~ /\b(?:BUG|BUG_ON)\b/) {
+# do not use BUG() or variants
+ if ($line =~ /\b(?!AA_|BUILD_|DCCP_|IDA_|KVM_|RWLOCK_|snd_|SPIN_)(?:[a-zA-Z_]*_)?BUG(?:_ON)?(?:_[A-Z_]+)?\s*\(/) {
my $msg_level = \&WARN;
$msg_level = \&CHK if ($file);
&{$msg_level}("AVOID_BUG",
- "Avoid crashing the kernel - try using WARN_ON & recovery code rather than BUG() or BUG_ON()\n" . $herecurr);
+ "Do not crash the kernel unless it is unavoidable - use WARN_ON_ONCE & recovery code (if reasonable) rather than BUG() or variants.\n" . $herecurr);
}
# avoid LINUX_VERSION_CODE
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
mm-gup-replace-foll_numa-by-gup_can_follow_protnone.patch
mm-gup-use-gup_can_follow_protnone-also-in-gup-fast.patch
mm-fixup-documentation-regarding-pte_numa-and-prot_numa.patch
coding-stylerst-document-bug-and-warn-rules-do-not-crash-the-kernel.patch
checkpatch-warn-on-usage-of-vm_bug_on-and-other-bug-variants.patch
