Hi Yuyang,
FYI, we noticed the below changes on commit
445d95d7c384741d133251a9adac935866591c92 ("sched: Remove update_rq_runnable_avg")
+------------------------------------------+------------+------------+
| | 80213c03c4 | 445d95d7c3 |
+------------------------------------------+------------+------------+
| boot_successes | 7 | 10 |
| boot_failures | 0 | 5 |
| BUG:unable_to_handle_kernel | 0 | 5 |
| Oops | 0 | 5 |
| RIP:print_cfs_group_stats | 0 | 5 |
| Kernel_panic-not_syncing:Fatal_exception | 0 | 5 |
| backtrace:vfs_read | 0 | 5 |
| backtrace:SyS_read | 0 | 5 |
+------------------------------------------+------------+------------+
repeat count: 267
2014-10-10 18:20:23 ./case-anon-wx-rand-mt
2014-10-10 18:20:23 ./usemem --runtime 300 -t 4 --prealloc --random 514360832
[ 67.303839] BUG: unable to handle kernel NULL pointer dereference at 0000000000000040
[ 67.304014] IP: [<ffffffff810b1d52>] print_cfs_rq+0x4a3/0xa96
[ 67.304014] PGD 7cd1f067 PUD 7ccbe067 PMD 0
[ 67.315030] Oops: 0000 [#1] SMP
[ 67.315030] Modules linked in: snd_pcsp
[ 67.315030] CPU: 3 PID: 4013 Comm: sched_debug Not tainted 3.17.0-g4bb7030 #2846
[ 67.315030] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 67.315030] task: ffff88007c6ecb00 ti: ffff88007ccac000 task.ti: ffff88007ccac000
[ 67.315030] RIP: 0010:[<ffffffff810b1d52>] [<ffffffff810b1d52>] print_cfs_rq+0x4a3/0xa96
[ 67.315030] RSP: 0018:ffff88007ccafd60 EFLAGS: 00010086
[ 67.315030] RAX: ffff88011a814000 RBX: ffff88007c47afe8 RCX: 0000000000000513
[ 67.315030] RDX: ffff88007ccafd00 RSI: 0000000000000000 RDI: 0000000000001000
[ 67.315030] RBP: ffff88007ccafda8 R08: 0000000000000000 R09: 0000000000000001
[ 67.315030] R10: ffff88007ccafcc8 R11: 0000000000000000 R12: 0000000000000000
[ 67.315030] R13: 0000000000000000 R14: 0000000000000000 R15: ffffffffffffffff
[ 67.315030] FS: 00007f6216ddd700(0000) GS:ffff88011b400000(0000) knlGS:0000000000000000
[ 67.315030] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 67.315030] CR2: 0000000000000040 CR3: 000000007c6ce000 CR4: 00000000000006e0
[ 67.315030] Stack:
[ 67.315030] 0000002b20db6a16 0000000000000086 0000000000000000 0000000000000000
[ 67.315030] ffff88011afd47b8 0000000000000000 ffff88007c47afe8 00000000001d4700
[ 67.315030] 0000000000000000 ffff88007ccafde8 ffffffff810aac54 ffff88011afd4870
[ 67.315030] Call Trace:
[ 67.315030] [<ffffffff810aac54>] print_cfs_stats+0x99/0xe0
[ 67.315030] [<ffffffff810b14b5>] print_cpu+0x57d/0x955
[ 67.315030] [<ffffffff811685b7>] ? might_fault+0x59/0xb4
[ 67.315030] [<ffffffff810b18a4>] sched_debug_show+0x17/0x22
[ 67.315030] [<ffffffff811b66f8>] seq_read+0x16a/0x33e
[ 67.315030] [<ffffffff811cc9f2>] ? fsnotify+0x267/0x28c
[ 67.315030] [<ffffffff811e58f0>] proc_reg_read+0x48/0x67
[ 67.315030] [<ffffffff811e58a8>] ? proc_reg_write+0x67/0x67
[ 67.315030] [<ffffffff81197b2d>] vfs_read+0xa6/0x144
[ 67.315030] [<ffffffff811985c5>] SyS_read+0x51/0x92
[ 67.315030] [<ffffffff81b4c729>] system_call_fastpath+0x16/0x1b
[ 67.315030] Code: f0 00 00 00 31 c0 e8 d6 85 a8 00 49 8b 84 24 c8 00 00 00 48 85 db 48 8b 75 c8 48 8b 80 d8 00 00 00 4c 8b 24 f0 0f 84 17 03 00 00 <4d> 8b 6c 24 40 4c 89 ef e8 9b eb ff ff 4c 89 ef 48 89 45 d0 e8
[ 67.315030] RIP [<ffffffff810b1d52>] print_cfs_rq+0x4a3/0xa96
[ 67.315030] RSP <ffff88007ccafd60>
[ 67.315030] CR2: 0000000000000040
[ 67.315030] ---[ end trace c7479625085660d8 ]---
[ 67.315030] Kernel panic - not syncing: Fatal exception
Thanks,
Fengguang
On Sat, 11 Oct 2014 13:15:30 +0800
Fengguang Wu <[email protected]> wrote:
> FYI, we noticed the below changes on commit
>
> 445d95d7c384741d133251a9adac935866591c92 ("sched: Remove update_rq_runnable_avg")
>
> [ 67.303839] BUG: unable to handle kernel NULL pointer dereference at 0000000000000040
> [ 67.304014] IP: [<ffffffff810b1d52>] print_cfs_rq+0x4a3/0xa96
Well that one's pretty obvious:
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -68,14 +68,6 @@ static void print_cfs_group_stats(struct seq_file *m, int cpu, struct task_group
#define PN(F) \
SEQ_printf(m, " .%-30s: %lld.%06ld\n", #F, SPLIT_NS((long long)F))
- if (!se) {
- struct sched_avg *avg = &cpu_rq(cpu)->avg;
- P(avg->runnable_avg_sum);
- P(avg->runnable_avg_period);
- return;
- }
-
-
PN(se->exec_start);
PN(se->vruntime);
PN(se->sum_exec_runtime);
You can remove the P() calls from that if statement, but you can't
remove the whole thing because you will try to dereference a NULL se
immediately afterward if you do.
Yes, thanks.
How come it is sent to whole list. Please ignore this. Sorry.
On Sat, Oct 11, 2014 at 01:00:48AM -0500, Chuck Ebbert wrote:
> On Sat, 11 Oct 2014 13:15:30 +0800
> Fengguang Wu <[email protected]> wrote:
>
> > FYI, we noticed the below changes on commit
> >
> > 445d95d7c384741d133251a9adac935866591c92 ("sched: Remove update_rq_runnable_avg")
> >
> > [ 67.303839] BUG: unable to handle kernel NULL pointer dereference at 0000000000000040
> > [ 67.304014] IP: [<ffffffff810b1d52>] print_cfs_rq+0x4a3/0xa96
>
> Well that one's pretty obvious:
>
>
> --- a/kernel/sched/debug.c
> +++ b/kernel/sched/debug.c
> @@ -68,14 +68,6 @@ static void print_cfs_group_stats(struct seq_file *m, int cpu, struct task_group
> #define PN(F) \
> SEQ_printf(m, " .%-30s: %lld.%06ld\n", #F, SPLIT_NS((long long)F))
>
> - if (!se) {
> - struct sched_avg *avg = &cpu_rq(cpu)->avg;
> - P(avg->runnable_avg_sum);
> - P(avg->runnable_avg_period);
> - return;
> - }
> -
> -
> PN(se->exec_start);
> PN(se->vruntime);
> PN(se->sum_exec_runtime);
>
>
> You can remove the P() calls from that if statement, but you can't
> remove the whole thing because you will try to dereference a NULL se
> immediately afterward if you do.
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/