Documentation: add reference from dynamic debug to loglevel kernel params

This is useful information for somebody who has managed to dig into
enabling debug output, but is wondering why there is no

Documentation: add reference from dynamic debug to loglevel kernel params

This is useful information for somebody who has managed to dig into
enabling debug output, but is wondering why there is no such output
appearing on the console.

Signed-off-by: Daniel Lublin <[email protected]>
Signed-off-by: Jonathan Corbet <[email protected]>
Link: https://lore.kernel.org/r/4633bdb82c1c7c014d79840887878624a55c59f8.1720533043.git.daniel@lublin.se

show more ...

Documentation: Remove redundant file names from examples

Since most examples use the ddcmd alias, remove the redundant file names

Signed-off-by: Rex Nie <[email protected]>
Signed-off-by: Jon

Documentation: Remove redundant file names from examples

Since most examples use the ddcmd alias, remove the redundant file names

Signed-off-by: Rex Nie <[email protected]>
Signed-off-by: Jonathan Corbet <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

show more ...

Documentation: fix typo in dynamic-debug howto

Signed-off-by: Jade Lovelace <[email protected]>
Signed-off-by: Jonathan Corbet <[email protected]>
Message-ID: <[email protected]>

dyndbg: add source filename to prefix

Printing the line number without the file is of limited usefulness.

Knowing the filename also makes it also easier to relate the logged
information to the cont

dyndbg: add source filename to prefix

Printing the line number without the file is of limited usefulness.

Knowing the filename also makes it also easier to relate the logged
information to the controlfile.

Example:

# modprobe test_dynamic_debug
# echo 'file test_dynamic_debug.c =pfsl' > /proc/dynamic_debug/control
# echo 1 > /sys/module/test_dynamic_debug/parameters/do_prints
# dmesg | tail -2
[ 71.802212] do_cats:lib/test_dynamic_debug.c:103: test_dd: doing categories
[ 71.802227] do_levels:lib/test_dynamic_debug.c:123: test_dd: doing levels

Signed-off-by: Thomas Weißschuh <[email protected]>
Acked-by: Jim Cromie <[email protected]>
Acked-by: Jason Baron <[email protected]>
Reviewed-by: Luis Chamberlain <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

Documentation: admin-guide: correct spelling

Correct spelling problems for Documentation/admin-guide/ as reported
by codespell.

Signed-off-by: Randy Dunlap <[email protected]>
Reviewed-by: Muke

Documentation: admin-guide: correct spelling

Correct spelling problems for Documentation/admin-guide/ as reported
by codespell.

Signed-off-by: Randy Dunlap <[email protected]>
Reviewed-by: Mukesh Ojha <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Zefan Li <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: [email protected]
Cc: Alasdair Kergon <[email protected]>
Cc: Mike Snitzer <[email protected]>
Cc: [email protected]
Cc: Mauro Carvalho Chehab <[email protected]>
Cc: [email protected]
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jonathan Corbet <[email protected]>

show more ...

doc-dyndbg: edit dynamic-debug-howto for brevity, audience

Rework/modernize docs:

- use /proc/dynamic_debug/control in examples
its *always* there (when dyndbg is config'd), even when <debugfs>

doc-dyndbg: edit dynamic-debug-howto for brevity, audience

Rework/modernize docs:

- use /proc/dynamic_debug/control in examples
its *always* there (when dyndbg is config'd), even when <debugfs> is not.
drop <debugfs> talk, its a distraction here.

- alias ddcmd='echo $* > /proc/dynamic_debug/control
focus on args: declutter, hide boilerplate, make pwd independent.

- swap sections: Viewing before Controlling. control file as Catalog.

- focus on use by a system administrator
add an alias to make examples more readable
drop grep-101 lessons, admins know this.

- use init/main.c as 1st example, thread it thru doc where useful.
everybodys kernel boots, runs these.

- add *prdbg* api section
to the bottom of the file, its for developers more than admins.
move list of api functions there.

- simplify - drop extra words, phrases, sentences.

- add "decorator" flags line to unify "prefix", trim fmlt descriptions

CC: [email protected]
Signed-off-by: Jim Cromie <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

doc-dyndbg: describe "class CLASS_NAME" query support

Add an explanation of the new "class CLASS_NAME" syntax and meaning,
noting that the module determines if CLASS_NAME applies to it.

Signed-off-

doc-dyndbg: describe "class CLASS_NAME" query support

Add an explanation of the new "class CLASS_NAME" syntax and meaning,
noting that the module determines if CLASS_NAME applies to it.

Signed-off-by: Jim Cromie <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

dyndbg: refine verbosity 1-4 summary-detail

adjust current v*pr_info() calls to fit an overview..detail scheme:

1- module level activity: add/remove, etc
2- command ingest, splitting, summary of ef

dyndbg: refine verbosity 1-4 summary-detail

adjust current v*pr_info() calls to fit an overview..detail scheme:

1- module level activity: add/remove, etc
2- command ingest, splitting, summary of effects.
per >control write
3- command parsing: op, flags, search terms
4- per-site change msg
can yield ~3k x 2 logs per echo "+p;-p" > command.

Summarize these 4 levels in MODULE_PARM_DESC, and update verbose=3 in Doc.

2- is new, to isolate a problem where a stress-test script (which
feeds ~4kb multi-command strings) would produce short writes,
truncating last command and causing parsing errors, which confused
test results. The script fix was to use syswrite, to deliver full
proper commands.

4- gets per-callsite "changed:" pr-infos, which are very noisy during
stress tests, and formerly obscured v1-3 messages, and overwhelmed the
static-key workload being tested.

The verbose parameter has previously seen adjustment:
commit 481c0e33f1e7 ("dyndbg: refine debug verbosity; 1 is basic, 2 more chatty")

The script driving these adjustments is:

!/usr/bin/perl -w

=for Doc

1st purpose was to benchmark the effect of wildcard queries on query
performance; if wildcards are risk free cheap enough, we can deploy
them in the (floating) format search. 1st finding: wildcards take 2x
as long to process.

2nd purpose was to benchmark real static-key changes VS simple flag
changes. Found ~100x decrease for the hard work.

The script maximizes workload per >control by packing it a ~4kb
string of "+p; -p;" commands; this uncovered some broken stuff.

The 85th query failed, and appears to be truncated, so is gramatically
incorrect. Its either an error here, or in the kernel. Its not
happening atm, retest.

Plot thickens: fail only happens doing +-p, not +-mf, likely load
dependent. Error remains consistent. Looks like a short write,
longer on writer than kernel-reader. Try syswrite on handle to
control this. That fixed short write.

=cut

use Getopt::Std;

getopts('vN:k:', \my %opts) or die <<EOH;
$0 options:
-v verbose
-k=n kernel dyndbg verbosity
-N=n number of loops.. tbrc
EOH
$opts{N} //= 10; # !undef, 0 tests too long.

my $ctrl = '/proc/dynamic_debug/control';

vx($opts{k}) if defined $opts{k}; # works on -k0

open(my $CTL, '>', $ctrl) or die "cant open $ctrl for writing: $!\n";

sub vx {
my $arg = shift;
my $cmd = "echo $arg > /sys/module/dynamic_debug/parameters/verbose";
system($cmd);
warn("vx problem: rc:$? err:$! qry: $cmd\n") if ($?);
}

sub qryOK {
my $qry = shift;

print "syntax test: <\n$qry>\n" if $opts{v};
my $bytes = syswrite $CTL, $qry;
printf "short read: $bytes / %d\n", length $qry if $bytes < length $qry;
if ($?) {
warn "rc:$? err:$! qry: $qry\n";
return 0;
}
return 1;
}

sub build_queries {
my ($cmd, $flags, $ct) = @_;

# build experiment and reference queries

my $cycle = " $cmd +$flags # on ; $cmd -$flags # off \n";
my $ref = " +$flags ; -$flags \n";

my $len = length $cycle;
my $max = int(4096 / $len); # break/fit to buffer size
$ct |= $max;
print "qry: ct:$max x << \n$cycle >>\n";

return unless qryOK($ref);
return unless qryOK($cycle);

my $wild = $cycle x $ct;
my $empty = $ref x $ct;

printf "len: %d, %d\n", length $wild, length $empty;

return { trial => $wild,
ref => $empty,
probe => $cycle,
zero => $ref,
count => $ct,
max => $max
};
}

my $query_set = build_queries(' file "*" module "*" func "*" ', "mf");

qryOK($query_set->{zero});
qryOK($query_set->{probe});

qryOK($query_set->{ref});
qryOK($query_set->{trial});

use Benchmark;
sub dobatch {
my ($cmd, $flags, $reps, $ct) = @_;
$reps ||= $opts{N};

my $qs = build_queries($cmd, $flags, $ct);

timethese($reps,
{
wildcards => sub {
syswrite $CTL, $qs->{trial};
},
no_search => sub {
syswrite $CTL, $qs->{ref};
}
}
);
}

sub bench_static_key_toggle {
vx 0;
dobatch(' file "*" module "*" func "*" ', "mf");
dobatch(' file "*" module "*" func "*" ', "p");
}

sub bench_verbose_levels {
for my $i (0..4) {
vx $i;
dobatch(' file "*" module "*" func "*" ', "mf");
}
}

bench_static_key_toggle();

__END__

Heres how the test-script runs:

:: verbose=3 parsing info

[ 48.401646] dyndbg: query 95: "file "*" module "*" func "*" -mf # off " mod:*
[ 48.402040] dyndbg: split into words: "file" "*" "module" "*" "func" "*" "-mf"
[ 48.402456] dyndbg: op='-'
[ 48.402615] dyndbg: flags=0x6
[ 48.402779] dyndbg: *flagsp=0x0 *maskp=0xfffffff9
[ 48.403033] dyndbg: parsed: func="*" file="*" module="*" format="" lineno=0-0
[ 48.403674] dyndbg: applied: func="*" file="*" module="*" format="" lineno=0-0

:: verbose=2 >control summary.
~300k site matches/changes per 4kb command

[ 48.404063] dyndbg: processed 96 queries, with 296160 matches, 0 errs

:: 2 queries against each other, no-search vs all-wildcard-search

qry: ct:48 x <<
file "*" module "*" func "*" +mf # on ; file "*" module "*" func "*" -mf # off
>>
len: 4080, 576
Benchmark: timing 10 iterations of no_search, wildcards...
no_search: 0 wallclock secs ( 0.00 usr + 0.03 sys = 0.03 CPU) @ 333.33/s (n=10)
(warning: too few iterations for a reliable count)
wildcards: 0 wallclock secs ( 0.00 usr + 0.09 sys = 0.09 CPU) @ 111.11/s (n=10)
(warning: too few iterations for a reliable count)

:: 2 queries, both doing real work / changing stati-key states.

qry: ct:49 x <<
file "*" module "*" func "*" +p # on ; file "*" module "*" func "*" -p # off
>>
len: 4067, 490
Benchmark: timing 10 iterations of no_search, wildcards...
no_search: 20 wallclock secs ( 0.00 usr + 20.36 sys = 20.36 CPU) @ 0.49/s (n=10)
wildcards: 21 wallclock secs ( 0.00 usr + 21.08 sys = 21.08 CPU) @ 0.47/s (n=10)
bash-5.1#

Thats 150k static-key-toggles / sec
~600x slower than simple flags
on qemu --smp 3 run

Signed-off-by: Jim Cromie <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

Documentation: dyndbg: Improve cli param examples

Jim pointed out that using $module.dyndbg= is always a more flexible
choice for using dynamic debug on the command line. The $module.dyndbg
style is

Documentation: dyndbg: Improve cli param examples

Jim pointed out that using $module.dyndbg= is always a more flexible
choice for using dynamic debug on the command line. The $module.dyndbg
style is checked at boot and handles if $module is a builtin. If it is
actually a loadable module, it is handled again later when the module is
loaded.

If you just use dyndbg="module $module +p" dynamic debug is only enabled
when $module is a builtin.

It was recommended to illustrate wildcard usage as well.

Suggested-by: Jim Cromie <[email protected]>
Signed-off-by: Andrew Halaney <[email protected]>
Signed-off-by: Jason Baron <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

dyndbg: Remove support for ddebug_query param

This param has been deprecated for a very long time now, let's rip it
out.

Signed-off-by: Andrew Halaney <[email protected]>
Signed-off-by: Jason Bar

dyndbg: Remove support for ddebug_query param

This param has been deprecated for a very long time now, let's rip it
out.

Signed-off-by: Andrew Halaney <[email protected]>
Signed-off-by: Jason Baron <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

Documentation: dynamic-debug-howto: fix example

dynamic debug is "expecting pairs of match-spec <value>" so the example
for all files of which the paths include "usb" there is "file" missing.

Signe

Documentation: dynamic-debug-howto: fix example

dynamic debug is "expecting pairs of match-spec <value>" so the example
for all files of which the paths include "usb" there is "file" missing.

Signed-off-by: Martin Kepplinger <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jonathan Corbet <[email protected]>

show more ...

Revert "dyndbg: accept query terms like file=bar and module=foo"

This reverts commit 14775b04964264189caa4a0862eac05dab8c0502 as there
were still some parsing problems with it, and the follow-on pat

Revert "dyndbg: accept query terms like file=bar and module=foo"

This reverts commit 14775b04964264189caa4a0862eac05dab8c0502 as there
were still some parsing problems with it, and the follow-on patch for
it.

Let's revisit it later, just drop it for now.

Cc: <[email protected]>
Cc: Jim Cromie <[email protected]>
Reported-by: Naresh Kamboju <[email protected]>
Cc: Stephen Rothwell <[email protected]>
Fixes: 14775b049642 ("dyndbg: accept query terms like file=bar and module=foo")
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

dyndbg: accept query terms like file=bar and module=foo

Current code expects "keyword" "arg" as 2 words, space separated.
Change to also accept "keyword=arg" form as well, and drop !(nwords%2)
requi

dyndbg: accept query terms like file=bar and module=foo

Current code expects "keyword" "arg" as 2 words, space separated.
Change to also accept "keyword=arg" form as well, and drop !(nwords%2)
requirement. Then in rest of function, use new keyword, arg variables
instead of word[i], word[i+1]

Acked-by: <[email protected]>
Signed-off-by: Jim Cromie <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

dyndbg: accept 'file foo.c:func1' and 'file foo.c:10-100'

Accept these additional query forms:

echo "file $filestr +_" > control

path/to/file.c:100 # as from control, column 1
pat

dyndbg: accept 'file foo.c:func1' and 'file foo.c:10-100'

Accept these additional query forms:

echo "file $filestr +_" > control

path/to/file.c:100 # as from control, column 1
path/to/file.c:1-100 # or any legal line-range
path/to/file.c:func_A # as from an editor/browser
path/to/file.c:drm_* # wildcards still work
path/to/file.c:*_foo # lead wildcard too

1st 2 examples are treated as line-ranges, 3-5 are treated as func's

Doc these changes, and sprinkle in a few extra wild-card examples and
trailing # explanation texts.

Acked-by: <[email protected]>
Signed-off-by: Jim Cromie <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

dyndbg-docs: initialization is done early, not arch

since cf964976484 in 2012, initialization is done with early_initcall,
update the Docs, which still say arch_initcall.

Acked-by: <[email protected]

dyndbg-docs: initialization is done early, not arch

since cf964976484 in 2012, initialization is done with early_initcall,
update the Docs, which still say arch_initcall.

Acked-by: <[email protected]>
Signed-off-by: Jim Cromie <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

dyndbg-docs: eschew file /full/path query in docs

Regarding:
commit 2b6783191da7 ("dynamic_debug: add trim_prefix() to provide source-root relative paths")
commit a73619a845d5 ("kbuild: use -fmacro-

dyndbg-docs: eschew file /full/path query in docs

Regarding:
commit 2b6783191da7 ("dynamic_debug: add trim_prefix() to provide source-root relative paths")
commit a73619a845d5 ("kbuild: use -fmacro-prefix-map to make __FILE__ a relative path")

2nd commit broke dynamic-debug's "file $fullpath" query form, but
nobody noticed because 1st commit had trimmed prefixes from
control-file output, so the click-copy-pasting of fullpaths into new
queries had ceased; that query form became unused.

Removing the function is cleanest, but it could be useful in
old-compiler corner cases, where __FILE__ still has /full/path,
and it safely does nothing otherwize.

So instead, quietly deprecate "file /full/path" query form, by
removing all /full/paths examples in the docs. I skipped adding a
back-compat note.

Acked-by: <[email protected]>
Signed-off-by: Jim Cromie <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

dynamic_debug: add an option to enable dynamic debug for modules only

Instead of enabling dynamic debug globally with CONFIG_DYNAMIC_DEBUG,
CONFIG_DYNAMIC_DEBUG_CORE will only enable core function o

dynamic_debug: add an option to enable dynamic debug for modules only

Instead of enabling dynamic debug globally with CONFIG_DYNAMIC_DEBUG,
CONFIG_DYNAMIC_DEBUG_CORE will only enable core function of dynamic
debug. With the DYNAMIC_DEBUG_MODULE defined for any modules, dynamic
debug will be tied to them.

This is useful for people who only want to enable dynamic debug for
kernel modules without worrying about kernel image size and memory
consumption is increasing too much.

[[email protected]: v2]
Link: http://lkml.kernel.org/r/[email protected]

Signed-off-by: Orson Zhai <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Acked-by: Greg Kroah-Hartman <[email protected]>
Acked-by: Petr Mladek <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Jason Baron <[email protected]>
Cc: Randy Dunlap <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

dynamic_debug: allow to work if debugfs is disabled

With the realization that having debugfs enabled on "production" systems
is generally not a good idea, debugfs is being disabled from more and
mor

dynamic_debug: allow to work if debugfs is disabled

With the realization that having debugfs enabled on "production" systems
is generally not a good idea, debugfs is being disabled from more and
more platforms over time. However, the functionality of dynamic
debugging still is needed at times, and since it relies on debugfs for
its user api, having debugfs disabled also forces dynamic debug to be
disabled.

To get around this, also create the "control" file for dynamic_debug in
procfs. This allows people turn on debugging as needed at runtime for
individual driverfs and subsystems.

Reported-by: many different companies
Cc: Jason Baron <[email protected]>
Acked-by: Will Deacon <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

Documentation: dynamic-debug: fix wildcard description

Fix grammar about wildcards and insert a space between sentences.

Signed-off-by: Randy Dunlap <[email protected]>
Cc: Jason Baron <jbaron@

Documentation: dynamic-debug: fix wildcard description

Fix grammar about wildcards and insert a space between sentences.

Signed-off-by: Randy Dunlap <[email protected]>
Cc: Jason Baron <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: [email protected]
Cc: Will Korteland <[email protected]>
Signed-off-by: Jonathan Corbet <[email protected]>

show more ...

Documentation: dynamic_debug: fix a couple of typos

Fix a few "typos" in dynamic-debug-howto.rst.

s/dyndbg_query/ddebug_query/
s/sysfs/debugfs/

Signed-off-by: Randy Dunlap <[email protected]>

Documentation: dynamic_debug: fix a couple of typos

Fix a few "typos" in dynamic-debug-howto.rst.

s/dyndbg_query/ddebug_query/
s/sysfs/debugfs/

Signed-off-by: Randy Dunlap <[email protected]>
Cc: Jason Baron <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: [email protected]
Signed-off-by: Jonathan Corbet <[email protected]>

show more ...

dynamic_debug documentation: minor fixes

Fix minor typo.

Fix missing words in explaining parsing of last line number.

Link: http://lkml.kernel.org/r/ebb7ff42-4945-103f-d5b4-f07a6f3343a7@infradead.

dynamic_debug documentation: minor fixes

Fix minor typo.

Fix missing words in explaining parsing of last line number.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Randy Dunlap <[email protected]>
Cc: Jason Baron <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

dynamic-debug-howto: Correct echo -c to -n

Two of the example command lines use an argument to echo of "-c" which
isn't valid in (most versions of) echo causing these examples to fail.
Correct the a

dynamic-debug-howto: Correct echo -c to -n

Two of the example command lines use an argument to echo of "-c" which
isn't valid in (most versions of) echo causing these examples to fail.
Correct the argument to "-n" which works correctly.

Signed-off-by: Steven Price <[email protected]>
Signed-off-by: Jonathan Corbet <[email protected]>

show more ...

docs-rst: create an user's manual book

Place README, REPORTING-BUGS, SecurityBugs and kernel-parameters
on an user's manual book.

As we'll be numbering the user's manual, remove the manual
numberin

docs-rst: create an user's manual book

Place README, REPORTING-BUGS, SecurityBugs and kernel-parameters
on an user's manual book.

As we'll be numbering the user's manual, remove the manual
numbering from SecurityBugs.

Signed-off-by: Mauro Carvalho Chehab <[email protected]>

show more ...