Commit 69d517e6 authored by David Hildenbrand's avatar David Hildenbrand Committed by Jonathan Corbet
Browse files

checkpatch: warn on usage of VM_BUG_ON() and other BUG variants 

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@mail.gmail.com



Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20220923113426.52871-3-david@redhat.com


Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent 1cfd9d7e

scripts/checkpatch.pl

+3 −3
Original line number Diff line number Diff line
@@ -4695,12 +4695,12 @@ 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 absolutely unavoidable--use WARN_ON_ONCE() plus recovery code (if feasible) instead of BUG() or variants\n" . $herecurr);

		}



# avoid LINUX_VERSION_CODE