diff mbox series

[v2,2/2] checkpatch: warn on usage of VM_BUG_ON() and other BUG variants

Message ID 20220923113426.52871-3-david@redhat.com (mailing list archive)
State New
Headers show
Series coding-style.rst: document BUG() and WARN() rules | expand

Commit Message

David Hildenbrand Sept. 23, 2022, 11:34 a.m. UTC
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: David Hildenbrand <david@redhat.com>
---
 scripts/checkpatch.pl | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 79e759aac543..5ca0039f216a 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -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