[v2] sched/rt: move back to RT_GROUP_SCHED and rename it child
Commit Message
The member back in struct sched_rt_entity only related to RT_GROUP_SCHED,
it should not place out of RT_GROUP_SCHED, move back to RT_GROUP_SCHED
and rename it child.
Init child in init_tg_rt_entry(). Also, add WARN_ON_ONCE if parent is
NULL, because parent is only NULL when rt_se is NULL.
Introduce for_each_sched_rt_entity_reverse() to iterate rt_entity from
top to down.
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
---
V1 -> V2: Add WARN_ON_ONCE in init_tg_rt_entry().
---
include/linux/sched.h | 2 +-
kernel/sched/rt.c | 29 +++++++++++++++++------------
2 files changed, 18 insertions(+), 13 deletions(-)
Comments
Hello,
kernel test robot noticed "WARNING:at_kernel/sched/rt.c:#init_tg_rt_entry" on:
commit: 93f769bf3e5e50825784e72db9be3b5ab44292ab ("[PATCH v2] sched/rt: move back to RT_GROUP_SCHED and rename it child")
url: https://github.com/intel-lab-lkp/linux/commits/Yajun-Deng/sched-rt-move-back-to-RT_GROUP_SCHED-and-rename-it-child/20230802-102608
base: https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git 4efcc8bc7e08c09c58a2f5cbc2096fbda5b7cf5e
patch link: https://lore.kernel.org/all/20230802022408.529208-1-yajun.deng@linux.dev/
patch subject: [PATCH v2] sched/rt: move back to RT_GROUP_SCHED and rename it child
in testcase: boot
compiler: clang-16
test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G
(please refer to attached dmesg/kmsg for entire log/backtrace)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <oliver.sang@intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202308031034.4369b15b-oliver.sang@intel.com
[ 10.946775][ T1] systemd[1]: RTC configured in localtime, applying delta of 0 minutes to system time.
[ 10.955700][ T1] systemd[1]: Inserted module 'autofs4'
[ 10.980165][ T1] ------------[ cut here ]------------
[ 10.980563][ T1] WARNING: CPU: 0 PID: 1 at kernel/sched/rt.c:231 init_tg_rt_entry+0xb1/0xf0
[ 10.981123][ T1] Modules linked in: autofs4
[ 10.981413][ T1] CPU: 0 PID: 1 Comm: systemd Tainted: G T 6.5.0-rc2-00018-g93f769bf3e5e #1 4d2b47299fa695b94fbb133b8210d53b6ca7680c
[ 10.982395][ T1] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
[ 10.983049][ T1] EIP: init_tg_rt_entry+0xb1/0xf0
[ 10.983366][ T1] Code: da 31 c9 6a 00 e8 df b1 0d 00 83 c4 04 8b 4d 0c 8b 41 24 89 46 20 89 7e 24 89 4e 1c 89 71 18 8d 46 08 89 46 08 89 46 0c eb 15 <0f> 0b b8
98 c0 68 c2 89 da 31 c9 6a 00 e8 ad b1 0d 00 83 c4 04 5e
[ 10.984589][ T1] EAX: 00000001 EBX: 00000001 ECX: 00000000 EDX: ffffffff
[ 10.985039][ T1] ESI: ee1c0a40 EDI: ed807400 EBP: c02abf04 ESP: c02abef8
[ 10.985476][ T1] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 EFLAGS: 00210246
[ 10.986233][ T1] CR0: 80050033 CR2: b7d2e260 CR3: 2e147000 CR4: 00040690
[ 10.986678][ T1] Call Trace:
[ 10.986887][ T1] ? show_regs+0x53/0x60
[ 10.987155][ T1] ? init_tg_rt_entry+0xb1/0xf0
[ 10.987469][ T1] ? __warn+0xae/0x270
[ 10.987742][ T1] ? init_tg_rt_entry+0xb1/0xf0
[ 10.988055][ T1] ? init_tg_rt_entry+0xb1/0xf0
[ 10.988362][ T1] ? report_bug+0xaf/0x130
[ 10.988653][ T1] ? exc_overflow+0x40/0x40
[ 10.988939][ T1] ? handle_bug+0x2c/0x50
[ 10.989210][ T1] ? exc_invalid_op+0x17/0x40
[ 10.989506][ T1] ? handle_exception+0x101/0x101
[ 10.989858][ T1] ? exc_overflow+0x40/0x40
[ 10.990147][ T1] ? init_tg_rt_entry+0xb1/0xf0
[ 10.990453][ T1] ? exc_overflow+0x40/0x40
[ 10.990736][ T1] ? init_tg_rt_entry+0xb1/0xf0
[ 10.991042][ T1] alloc_rt_sched_group+0x315/0x370
[ 10.991369][ T1] sched_create_group+0x3b/0x70
[ 10.991674][ T1] sched_autogroup_create_attach+0x4a/0x1f0
[ 10.992046][ T1] ksys_setsid+0xd2/0xe0
[ 10.992316][ T1] __ia32_sys_setsid+0xd/0x10
[ 10.992618][ T1] do_int80_syscall_32+0x7d/0xa0
[ 10.992934][ T1] ? exc_page_fault+0x112/0x160
[ 10.993240][ T1] entry_INT80_32+0xf0/0xf0
[ 10.993526][ T1] EIP: 0xb7f87092
[ 10.993789][ T1] Code: 00 00 00 e9 90 ff ff ff ff a3 24 00 00 00 68 30 00 00 00 e9 80 ff ff ff ff a3 f8 ff ff ff 66 90 00 00 00 00 00 00 00 00 cd 80 <c3> 8d b4 26 00 00 00 00 8d b6 00 00 00 00 8b 1c 24 c3 8d b4 26 00
[ 10.994983][ T1] EAX: ffffffda EBX: 005e4cb8 ECX: 00000000 EDX: ffffffff
[ 10.995420][ T1] ESI: bf95bb78 EDI: bf95bb88 EBP: bf95bc48 ESP: bf95baf8
[ 10.995855][ T1] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b EFLAGS: 00200202
[ 10.996332][ T1] irq event stamp: 4152391
[ 10.996616][ T1] hardirqs last enabled at (4152399): [<c10d9014>] __up_console_sem+0x64/0xb0
[ 10.997170][ T1] hardirqs last disabled at (4152406): [<c10d8ffb>] __up_console_sem+0x4b/0xb0
[ 10.997716][ T1] softirqs last enabled at (4152356): [<c1c9fddc>] __do_softirq+0x4cc/0x535
[ 10.998289][ T1] softirqs last disabled at (4152423): [<c100c7c5>] do_softirq_own_stack+0x55/0x60
[ 10.998863][ T1] ---[ end trace 0000000000000000 ]---
To reproduce:
# build kernel
cd linux
cp config-6.5.0-rc2-00018-g93f769bf3e5e .config
make HOSTCC=clang-16 CC=clang-16 ARCH=i386 olddefconfig prepare modules_prepare bzImage modules
make HOSTCC=clang-16 CC=clang-16 ARCH=i386 INSTALL_MOD_PATH=<mod-install-dir> modules_install
cd <mod-install-dir>
find lib/ | cpio -o -H newc --quiet | gzip > modules.cgz
git clone https://github.com/intel/lkp-tests.git
cd lkp-tests
bin/lkp qemu -k <bzImage> -m modules.cgz job-script # job-script is attached in this email
# if come across any failure that blocks the test,
# please remove ~/.lkp and /lkp dir to run from a clean state.
@@ -594,8 +594,8 @@ struct sched_rt_entity {
unsigned short on_rq;
unsigned short on_list;
- struct sched_rt_entity *back;
#ifdef CONFIG_RT_GROUP_SCHED
+ struct sched_rt_entity *child;
struct sched_rt_entity *parent;
/* rq on which this entity is (to be) queued: */
struct rt_rq *rt_rq;
@@ -228,13 +228,13 @@ void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
if (!rt_se)
return;
- if (!parent)
- rt_se->rt_rq = &rq->rt;
- else
- rt_se->rt_rq = parent->my_q;
+ if (WARN_ON_ONCE(!parent))
+ return;
+ rt_se->rt_rq = parent->my_q;
rt_se->my_q = rt_rq;
rt_se->parent = parent;
+ parent->child = rt_se;
INIT_LIST_HEAD(&rt_se->run_list);
}
@@ -564,6 +564,9 @@ static inline struct task_group *next_task_group(struct task_group *tg)
#define for_each_sched_rt_entity(rt_se) \
for (; rt_se; rt_se = rt_se->parent)
+#define for_each_sched_rt_entity_reverse(rt_se) \
+ for (; rt_se; rt_se = rt_se->child)
+
static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
{
return rt_se->my_q;
@@ -669,6 +672,9 @@ typedef struct rt_rq *rt_rq_iter_t;
#define for_each_sched_rt_entity(rt_se) \
for (; rt_se; rt_se = NULL)
+#define for_each_sched_rt_entity_reverse(rt_se) \
+ for_each_sched_rt_entity(rt_se)
+
static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
{
return NULL;
@@ -1481,22 +1487,21 @@ static void __dequeue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flag
*/
static void dequeue_rt_stack(struct sched_rt_entity *rt_se, unsigned int flags)
{
- struct sched_rt_entity *back = NULL;
+ struct sched_rt_entity *root;
unsigned int rt_nr_running;
- for_each_sched_rt_entity(rt_se) {
- rt_se->back = back;
- back = rt_se;
- }
+ for_each_sched_rt_entity(rt_se)
+ root = rt_se;
- rt_nr_running = rt_rq_of_se(back)->rt_nr_running;
+ rt_nr_running = rt_rq_of_se(root)->rt_nr_running;
- for (rt_se = back; rt_se; rt_se = rt_se->back) {
+ rt_se = root;
+ for_each_sched_rt_entity_reverse(rt_se) {
if (on_rt_rq(rt_se))
__dequeue_rt_entity(rt_se, flags);
}
- dequeue_top_rt_rq(rt_rq_of_se(back), rt_nr_running);
+ dequeue_top_rt_rq(rt_rq_of_se(root), rt_nr_running);
}
static void enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)