Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge branch 'rcu/misc' into next
- In order to prepare the layout for nohz_full work deferral to
user exit, the context tracking state must shrink the counter
of transitions to/from RCU not watching. The only possible hazard
is to trigger wrap-around more easily, delaying a bit grace periods
when that happens. This should be a rare event though. Yet add
debugging and torture code to test that assumption.
- Fix memory leak on locktorture module
- Annotate accesses in rculist_nulls.h to prevent from KCSAN warnings.
On recent discussions, we also concluded that all those WRITE_ONCE()
and READ_ONCE() on list APIs deserve appropriate comments. Something
to be expected for the next cycle.
- Provide a script to apply several configs to several commits with torture.
- Allow torture to reuse a build directory in order to save needless
rebuild time.
- Various cleanups.
+219
-31
+37
-7
include/linux/context_tracking_state.h
+37
-7
include/linux/context_tracking_state.h
···
18
18
CT_STATE_MAX = 4,
19
19
};
20
20
21
-
/* Odd value for watching, else even. */
22
-
#define CT_RCU_WATCHING CT_STATE_MAX
23
-
24
-
#define CT_STATE_MASK (CT_STATE_MAX - 1)
25
-
#define CT_RCU_WATCHING_MASK (~CT_STATE_MASK)
26
-
27
21
struct context_tracking {
28
22
#ifdef CONFIG_CONTEXT_TRACKING_USER
29
23
/*
···
38
44
#endif
39
45
};
40
46
47
+
/*
48
+
* We cram two different things within the same atomic variable:
49
+
*
50
+
* CT_RCU_WATCHING_START CT_STATE_START
51
+
* | |
52
+
* v v
53
+
* MSB [ RCU watching counter ][ context_state ] LSB
54
+
* ^ ^
55
+
* | |
56
+
* CT_RCU_WATCHING_END CT_STATE_END
57
+
*
58
+
* Bits are used from the LSB upwards, so unused bits (if any) will always be in
59
+
* upper bits of the variable.
60
+
*/
41
61
#ifdef CONFIG_CONTEXT_TRACKING
62
+
#define CT_SIZE (sizeof(((struct context_tracking *)0)->state) * BITS_PER_BYTE)
63
+
64
+
#define CT_STATE_WIDTH bits_per(CT_STATE_MAX - 1)
65
+
#define CT_STATE_START 0
66
+
#define CT_STATE_END (CT_STATE_START + CT_STATE_WIDTH - 1)
67
+
68
+
#define CT_RCU_WATCHING_MAX_WIDTH (CT_SIZE - CT_STATE_WIDTH)
69
+
#define CT_RCU_WATCHING_WIDTH (IS_ENABLED(CONFIG_RCU_DYNTICKS_TORTURE) ? 2 : CT_RCU_WATCHING_MAX_WIDTH)
70
+
#define CT_RCU_WATCHING_START (CT_STATE_END + 1)
71
+
#define CT_RCU_WATCHING_END (CT_RCU_WATCHING_START + CT_RCU_WATCHING_WIDTH - 1)
72
+
#define CT_RCU_WATCHING BIT(CT_RCU_WATCHING_START)
73
+
74
+
#define CT_STATE_MASK GENMASK(CT_STATE_END, CT_STATE_START)
75
+
#define CT_RCU_WATCHING_MASK GENMASK(CT_RCU_WATCHING_END, CT_RCU_WATCHING_START)
76
+
77
+
#define CT_UNUSED_WIDTH (CT_RCU_WATCHING_MAX_WIDTH - CT_RCU_WATCHING_WIDTH)
78
+
79
+
static_assert(CT_STATE_WIDTH +
80
+
CT_RCU_WATCHING_WIDTH +
81
+
CT_UNUSED_WIDTH ==
82
+
CT_SIZE);
83
+
42
84
DECLARE_PER_CPU(struct context_tracking, context_tracking);
43
-
#endif
85
+
#endif /* CONFIG_CONTEXT_TRACKING */
44
86
45
87
#ifdef CONFIG_CONTEXT_TRACKING_USER
46
88
static __always_inline int __ct_state(void)
+3
-3
include/linux/rculist_nulls.h
+3
-3
include/linux/rculist_nulls.h
···
138
138
139
139
if (last) {
140
140
WRITE_ONCE(n->next, last->next);
141
-
n->pprev = &last->next;
141
+
WRITE_ONCE(n->pprev, &last->next);
142
142
rcu_assign_pointer(hlist_nulls_next_rcu(last), n);
143
143
} else {
144
144
hlist_nulls_add_head_rcu(n, h);
···
148
148
/* after that hlist_nulls_del will work */
149
149
static inline void hlist_nulls_add_fake(struct hlist_nulls_node *n)
150
150
{
151
-
n->pprev = &n->next;
152
-
n->next = (struct hlist_nulls_node *)NULLS_MARKER(NULL);
151
+
WRITE_ONCE(n->pprev, &n->next);
152
+
WRITE_ONCE(n->next, (struct hlist_nulls_node *)NULLS_MARKER(NULL));
153
153
}
154
154
155
155
/**
+6
-2
kernel/locking/locktorture.c
+6
-2
kernel/locking/locktorture.c
···
103
103
.get = param_get_cpumask,
104
104
};
105
105
106
-
module_param_cb(bind_readers, <_bind_ops, &bind_readers, 0644);
107
-
module_param_cb(bind_writers, <_bind_ops, &bind_writers, 0644);
106
+
module_param_cb(bind_readers, <_bind_ops, &bind_readers, 0444);
107
+
module_param_cb(bind_writers, <_bind_ops, &bind_writers, 0444);
108
108
109
109
long torture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask, bool dowarn);
110
110
···
1211
1211
cxt.cur_ops->exit();
1212
1212
cxt.init_called = false;
1213
1213
}
1214
+
1215
+
free_cpumask_var(bind_readers);
1216
+
free_cpumask_var(bind_writers);
1217
+
1214
1218
torture_cleanup_end();
1215
1219
}
1216
1220
+15
kernel/rcu/Kconfig.debug
+15
kernel/rcu/Kconfig.debug
···
213
213
when looking for certain types of RCU usage bugs, for example,
214
214
too-short RCU read-side critical sections.
215
215
216
+
217
+
config RCU_DYNTICKS_TORTURE
218
+
bool "Minimize RCU dynticks counter size"
219
+
depends on RCU_EXPERT && !COMPILE_TEST
220
+
default n
221
+
help
222
+
This option sets the width of the dynticks counter to its
223
+
minimum usable value. This minimum width greatly increases
224
+
the probability of flushing out bugs involving counter wrap,
225
+
but it also increases the probability of extending grace period
226
+
durations. This Kconfig option should therefore be avoided in
227
+
production due to the consequent increased probability of OOMs.
228
+
229
+
This has no value for production and is only for testing.
230
+
216
231
endmenu # "RCU Debugging"
+1
-3
kernel/rcu/rcutorture.c
+1
-3
kernel/rcu/rcutorture.c
···
2438
2438
newstate = rcutorture_extend_mask(rtors.readstate, trsp);
2439
2439
WARN_ON_ONCE(newstate & RCUTORTURE_RDR_UPDOWN);
2440
2440
rcutorture_one_extend(&rtors.readstate, newstate, trsp, rtors.rtrsp++);
2441
-
if (!rcu_torture_one_read_start(&rtors, trsp, myid)) {
2442
-
rcutorture_one_extend(&rtors.readstate, 0, trsp, rtors.rtrsp);
2441
+
if (!rcu_torture_one_read_start(&rtors, trsp, myid))
2443
2442
return false;
2444
-
}
2445
2443
rtors.rtrsp = rcutorture_loop_extend(&rtors.readstate, trsp, rtors.rtrsp);
2446
2444
rcu_torture_one_read_end(&rtors, trsp);
2447
2445
return true;
+40
-16
tools/testing/selftests/rcutorture/bin/kvm-again.sh
+40
-16
tools/testing/selftests/rcutorture/bin/kvm-again.sh
···
31
31
if ! cp "$oldrun/scenarios" $T/scenarios.oldrun
32
32
then
33
33
# Later on, can reconstitute this from console.log files.
34
-
echo Prior run batches file does not exist: $oldrun/batches
34
+
echo Prior run scenarios file does not exist: $oldrun/scenarios
35
35
exit 1
36
36
fi
37
37
···
68
68
echo " --datestamp string"
69
69
echo " --dryrun"
70
70
echo " --duration minutes | <seconds>s | <hours>h | <days>d"
71
-
echo " --link hard|soft|copy"
71
+
echo " --link hard|soft|copy|inplace|inplace-force"
72
72
echo " --remote"
73
73
echo " --rundir /new/res/path"
74
74
echo "Command line: $scriptname $args"
···
121
121
shift
122
122
;;
123
123
--link)
124
-
checkarg --link "hard|soft|copy" "$#" "$2" 'hard\|soft\|copy' '^--'
124
+
checkarg --link "hard|soft|copy|inplace|inplace-force" "$#" "$2" 'hard\|soft\|copy\|inplace\|inplace-force' '^--'
125
125
case "$2" in
126
126
copy)
127
127
arg_link="cp -R"
···
131
131
;;
132
132
soft)
133
133
arg_link="cp -Rs"
134
+
;;
135
+
inplace)
136
+
arg_link="inplace"
137
+
rundir="$oldrun"
138
+
;;
139
+
inplace-force)
140
+
arg_link="inplace-force"
141
+
rundir="$oldrun"
134
142
;;
135
143
esac
136
144
shift
···
180
172
181
173
echo ---- Re-run results directory: $rundir
182
174
183
-
# Copy old run directory tree over and adjust.
184
-
mkdir -p "`dirname "$rundir"`"
185
-
if ! $arg_link "$oldrun" "$rundir"
175
+
if test "$oldrun" != "$rundir"
186
176
then
187
-
echo "Cannot copy from $oldrun to $rundir."
188
-
usage
177
+
# Copy old run directory tree over and adjust.
178
+
mkdir -p "`dirname "$rundir"`"
179
+
if ! $arg_link "$oldrun" "$rundir"
180
+
then
181
+
echo "Cannot copy from $oldrun to $rundir."
182
+
usage
183
+
fi
184
+
rm -f "$rundir"/*/{console.log,console.log.diags,qemu_pid,qemu-pid,qemu-retval,Warnings,kvm-test-1-run.sh.out,kvm-test-1-run-qemu.sh.out,vmlinux} "$rundir"/log
185
+
touch "$rundir/log"
186
+
echo $scriptname $args | tee -a "$rundir/log"
187
+
echo $oldrun > "$rundir/re-run"
188
+
if ! test -d "$rundir/../../bin"
189
+
then
190
+
$arg_link "$oldrun/../../bin" "$rundir/../.."
191
+
fi
192
+
else
193
+
# Check for a run having already happened.
194
+
find "$rundir" -name console.log -print > $T/oldrun-console.log
195
+
if test -s $T/oldrun-console.log
196
+
then
197
+
echo Run already took place in $rundir
198
+
if test "$arg_link" = inplace
199
+
then
200
+
usage
201
+
fi
202
+
fi
189
203
fi
190
-
rm -f "$rundir"/*/{console.log,console.log.diags,qemu_pid,qemu-pid,qemu-retval,Warnings,kvm-test-1-run.sh.out,kvm-test-1-run-qemu.sh.out,vmlinux} "$rundir"/log
191
-
touch "$rundir/log"
192
-
echo $scriptname $args | tee -a "$rundir/log"
193
-
echo $oldrun > "$rundir/re-run"
194
-
if ! test -d "$rundir/../../bin"
195
-
then
196
-
$arg_link "$oldrun/../../bin" "$rundir/../.."
197
-
fi
204
+
205
+
# Find runs to be done based on their qemu-cmd files.
198
206
for i in $rundir/*/qemu-cmd
199
207
do
200
208
cp "$i" $T
+116
tools/testing/selftests/rcutorture/bin/kvm-series.sh
+116
tools/testing/selftests/rcutorture/bin/kvm-series.sh
···
1
+
#!/bin/bash
2
+
# SPDX-License-Identifier: GPL-2.0+
3
+
#
4
+
# Usage: kvm-series.sh config-list commit-id-list [ kvm.sh parameters ]
5
+
#
6
+
# Tests the specified list of unadorned configs ("TREE01 SRCU-P" but not
7
+
# "CFLIST" or "3*TRACE01") and an indication of a set of commits to test,
8
+
# then runs each commit through the specified list of commits using kvm.sh.
9
+
# The runs are grouped into a -series/config/commit directory tree.
10
+
# Each run defaults to a duration of one minute.
11
+
#
12
+
# Run in top-level Linux source directory. Please note that this is in
13
+
# no way a replacement for "git bisect"!!!
14
+
#
15
+
# This script is intended to replace kvm-check-branches.sh by providing
16
+
# ease of use and faster execution.
17
+
18
+
T="`mktemp -d ${TMPDIR-/tmp}/kvm-series.sh.XXXXXX`"
19
+
trap 'rm -rf $T' 0
20
+
21
+
scriptname=$0
22
+
args="$*"
23
+
24
+
config_list="${1}"
25
+
if test -z "${config_list}"
26
+
then
27
+
echo "$0: Need a quoted list of --config arguments for first argument."
28
+
exit 1
29
+
fi
30
+
if test -z "${config_list}" || echo "${config_list}" | grep -q '\*'
31
+
then
32
+
echo "$0: Repetition ('*') not allowed in config list."
33
+
exit 1
34
+
fi
35
+
36
+
commit_list="${2}"
37
+
if test -z "${commit_list}"
38
+
then
39
+
echo "$0: Need a list of commits (e.g., HEAD^^^..) for second argument."
40
+
exit 2
41
+
fi
42
+
git log --pretty=format:"%h" "${commit_list}" > $T/commits
43
+
ret=$?
44
+
if test "${ret}" -ne 0
45
+
then
46
+
echo "$0: Invalid commit list ('${commit_list}')."
47
+
exit 2
48
+
fi
49
+
sha1_list=`cat $T/commits`
50
+
51
+
shift
52
+
shift
53
+
54
+
RCUTORTURE="`pwd`/tools/testing/selftests/rcutorture"; export RCUTORTURE
55
+
PATH=${RCUTORTURE}/bin:$PATH; export PATH
56
+
. functions.sh
57
+
58
+
ret=0
59
+
nfail=0
60
+
nsuccess=0
61
+
faillist=
62
+
successlist=
63
+
cursha1="`git rev-parse --abbrev-ref HEAD`"
64
+
ds="`date +%Y.%m.%d-%H.%M.%S`-series"
65
+
startdate="`date`"
66
+
starttime="`get_starttime`"
67
+
68
+
echo " --- " $scriptname $args | tee -a $T/log
69
+
echo " --- Results directory: " $ds | tee -a $T/log
70
+
71
+
for config in ${config_list}
72
+
do
73
+
sha_n=0
74
+
for sha in ${sha1_list}
75
+
do
76
+
sha1=${sha_n}.${sha} # Enable "sort -k1nr" to list commits in order.
77
+
echo Starting ${config}/${sha1} at `date` | tee -a $T/log
78
+
git checkout "${sha}"
79
+
time tools/testing/selftests/rcutorture/bin/kvm.sh --configs "$config" --datestamp "$ds/${config}/${sha1}" --duration 1 "$@"
80
+
curret=$?
81
+
if test "${curret}" -ne 0
82
+
then
83
+
nfail=$((nfail+1))
84
+
faillist="$faillist ${config}/${sha1}(${curret})"
85
+
else
86
+
nsuccess=$((nsuccess+1))
87
+
successlist="$successlist ${config}/${sha1}"
88
+
# Successful run, so remove large files.
89
+
rm -f ${RCUTORTURE}/$ds/${config}/${sha1}/{vmlinux,bzImage,System.map,Module.symvers}
90
+
fi
91
+
if test "${ret}" -eq 0
92
+
then
93
+
ret=${curret}
94
+
fi
95
+
sha_n=$((sha_n+1))
96
+
done
97
+
done
98
+
git checkout "${cursha1}"
99
+
100
+
echo ${nsuccess} SUCCESSES: | tee -a $T/log
101
+
echo ${successlist} | fmt | tee -a $T/log
102
+
echo | tee -a $T/log
103
+
echo ${nfail} FAILURES: | tee -a $T/log
104
+
echo ${faillist} | fmt | tee -a $T/log
105
+
if test -n "${faillist}"
106
+
then
107
+
echo | tee -a $T/log
108
+
echo Failures across commits: | tee -a $T/log
109
+
echo ${faillist} | tr ' ' '\012' | sed -e 's,^[^/]*/,,' -e 's/([0-9]*)//' |
110
+
sort | uniq -c | sort -k2n | tee -a $T/log
111
+
fi
112
+
echo Started at $startdate, ended at `date`, duration `get_starttime_duration $starttime`. | tee -a $T/log
113
+
echo Summary: Successes: ${nsuccess} Failures: ${nfail} | tee -a $T/log
114
+
cp $T/log tools/testing/selftests/rcutorture/res/${ds}
115
+
116
+
exit "${ret}"