[v2,2/3] checkpatch: handle new pr_<level>_cont macros
Commit Message
These new macros from include/linux/printk.h replace the usage of plain
pr_cont().
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
scripts/checkpatch.pl | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
Comments
On Fri, 2022-11-25 at 20:09 +0100, Thomas Weißschuh wrote:
> These new macros from include/linux/printk.h replace the usage of plain
> pr_cont().
[]
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 1e5e66ae5a52..fb1747639c9c 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -590,7 +590,7 @@ our $zero_initializer = qr{(?:(?:0[xX])?0+$Int_type?|NULL|false)\b};
>
> our $logFunctions = qr{(?x:
> printk(?:_ratelimited|_once|_deferred_once|_deferred|)|
> - (?:[a-z0-9]+_){1,2}(?:printk|emerg|alert|crit|err|warning|warn|notice|info|debug|dbg|vdbg|devel|cont|WARN)(?:_ratelimited|_once|)|
> + (?:[a-z0-9]+_){1,2}(?:printk|emerg|alert|crit|err|warning|warn|notice|info|debug|dbg|vdbg|devel|cont|WARN)(?:_ratelimited|_once|_cont|)|
OK
> TP_printk|
> WARN(?:_RATELIMIT|_ONCE|)|
> panic|
> @@ -6374,11 +6374,17 @@ sub process {
> }
>
> # check for logging continuations
> - if ($line =~ /\bprintk\s*\(\s*KERN_CONT\b|\bpr_cont\s*\(/) {
> + if ($line =~ /\bprintk\s*\(\s*KERN_CONT\b|\bpr_([a-z]+_)?cont\s*\(/) {
> WARN("LOGGING_CONTINUATION",
> "Avoid logging continuation uses where feasible\n" . $herecurr);
> }
OK
> +# check for logging continuations without explicit level
> + if ($line =~ /\bpr_cont\s*\(/) {
> + WARN("LOGGING_CONTINUATION_WITHOUT_LEVEL",
> + "Avoid logging continuation without level\n" . $herecurr);
> + }
> +
Not so sure about this one.
I think relatively few situations are going to require interleaving avoidance.
> # check for unnecessary use of %h[xudi] and %hh[xudi] in logging functions
> if (defined $stat &&
> $line =~ /\b$logFunctions\s*\(/ &&
On Fri 2022-11-25 12:17:05, Joe Perches wrote:
> On Fri, 2022-11-25 at 20:09 +0100, Thomas Weißschuh wrote:
> > These new macros from include/linux/printk.h replace the usage of plain
> > pr_cont().
> []
> > --- a/scripts/checkpatch.pl
> > +++ b/scripts/checkpatch.pl
> > @@ -590,7 +590,7 @@ our $zero_initializer = qr{(?:(?:0[xX])?0+$Int_type?|NULL|false)\b};
> > +# check for logging continuations without explicit level
> > + if ($line =~ /\bpr_cont\s*\(/) {
> > + WARN("LOGGING_CONTINUATION_WITHOUT_LEVEL",
> > + "Avoid logging continuation without level\n" . $herecurr);
> > + }
> > +
>
> Not so sure about this one.
>
> I think relatively few situations are going to require interleaving avoidance.
Well, the problem is generic and any pr_cont() is affected except for
NMI context on single CPU system.
I though about a generic solution. We could store the last used printk
log level per-process and per-CPU context. But it does not solve
the situation when an unrelated printk() is printed by a nested
function.
It is exactly the case with try_to_freeze_tasks() in the 3rd patch.
Simplified code:
int freeze_processes(void)
{
pr_info("Freezing user space processes ... ");
try_to_freeze_tasks(true);
pr_info_cont("done.");
}
, where
static int try_to_freeze_tasks(bool user_only)
{
[...]
if (todo) {
pr_err("Freezing of tasks %s after %d.%03d seconds "
[...]
}
I would personally add this check into checkpatch.pl. It might help
to make people aware about that pr_cont() is just the best effort.
Best Regards,
Petr
@@ -590,7 +590,7 @@ our $zero_initializer = qr{(?:(?:0[xX])?0+$Int_type?|NULL|false)\b};
our $logFunctions = qr{(?x:
printk(?:_ratelimited|_once|_deferred_once|_deferred|)|
- (?:[a-z0-9]+_){1,2}(?:printk|emerg|alert|crit|err|warning|warn|notice|info|debug|dbg|vdbg|devel|cont|WARN)(?:_ratelimited|_once|)|
+ (?:[a-z0-9]+_){1,2}(?:printk|emerg|alert|crit|err|warning|warn|notice|info|debug|dbg|vdbg|devel|cont|WARN)(?:_ratelimited|_once|_cont|)|
TP_printk|
WARN(?:_RATELIMIT|_ONCE|)|
panic|
@@ -6374,11 +6374,17 @@ sub process {
}
# check for logging continuations
- if ($line =~ /\bprintk\s*\(\s*KERN_CONT\b|\bpr_cont\s*\(/) {
+ if ($line =~ /\bprintk\s*\(\s*KERN_CONT\b|\bpr_([a-z]+_)?cont\s*\(/) {
WARN("LOGGING_CONTINUATION",
"Avoid logging continuation uses where feasible\n" . $herecurr);
}
+# check for logging continuations without explicit level
+ if ($line =~ /\bpr_cont\s*\(/) {
+ WARN("LOGGING_CONTINUATION_WITHOUT_LEVEL",
+ "Avoid logging continuation without level\n" . $herecurr);
+ }
+
# check for unnecessary use of %h[xudi] and %hh[xudi] in logging functions
if (defined $stat &&
$line =~ /\b$logFunctions\s*\(/ &&