lkml.org 
[lkml]   [2019]   [Nov]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Date
SubjectRe: [PATCH 17/23] y2038: time: avoid timespec usage in settimeofday()
On Fri, Nov 15, 2019 at 12:01 AM Abel Vesa <abelvesa@linux.com> wrote:
>
> On 19-11-08 22:12:16, Arnd Bergmann wrote:
> > The compat_get_timeval() and timeval_valid() interfaces
> > are deprecated and getting removed along with the definition
> > of struct timeval itself.
> >
> > Change the two implementations of the settimeofday()
> > system call to open-code these helpers and completely
> > avoid references to timeval.
> >

I'm not sure how we get to the RCU stall, but this is almost certainly another
symptom of a typo I had introduced in the patch, which others have also
reported. This is the the fix in today's linux-next:

--- a/kernel/time/time.c
+++ b/kernel/time/time.c
@@ -207,7 +207,7 @@ SYSCALL_DEFINE2(settimeofday, struct
__kernel_old_timeval __user *, tv,
get_user(new_ts.tv_nsec, &tv->tv_usec))
return -EFAULT;

- if (tv->tv_usec > USEC_PER_SEC)
+ if (new_ts->tv_usec > USEC_PER_SEC)
return -EINVAL;

new_ts.tv_nsec *= NSEC_PER_USEC;

Arnd

> I get the following rcu stalls due to this patch on riscv64 (on qemu):
>
> [root@riscv ~]# uname -a
> Linux riscv 5.4.0-rc6-00018-gadde74306a4b #112 SMP Fri Nov 15 00:46:20 EET 2019 riscv64 riscv64 riscv64 GNU/Linux
> [root@riscv ~]# [ 420.135710] rcu: INFO: rcu_sched self-detected stall
> on CPU
> [ 420.136839] rcu: 3-....: (99702 ticks this GP) idle=482/1/0x4000000000000002 softirq=3322/3322 fqs=48784
> [ 420.138917] (t=99768 jiffies g=4985 q=8343)
> [ 420.139772] Task dump for CPU 3:
> [ 420.140236] rdate R running task 0 254 1 0x00000008
> [ 420.142226] Call Trace:
> [ 420.142791] [<ffffffe000037954>] walk_stackframe+0x0/0xa6
> [ 420.143911] [<ffffffe000037aba>] show_stack+0x2a/0x34
> [ 420.145010] [<ffffffe0000569c8>] sched_show_task+0xf0/0x116
> [ 420.145996] [<ffffffe00005b502>] dump_cpu_task+0x3e/0x48
> [ 420.147073] [<ffffffe000084e5e>] rcu_dump_cpu_stacks+0x7c/0xb4
> [ 420.148243] [<ffffffe0000842f6>] rcu_sched_clock_irq+0x3d6/0x582
> [ 420.149349] [<ffffffe0000897b4>] update_process_times+0x1e/0x42
> [ 420.150306] [<ffffffe000093a34>] tick_sched_handle.isra.0+0x2a/0x3a
> [ 420.150997] [<ffffffe000093ce8>] tick_sched_timer+0x4e/0x92
> [ 420.151603] [<ffffffe000089eb6>] __hrtimer_run_queues+0xae/0x108
> [ 420.152639] [<ffffffe00008a5ac>] hrtimer_interrupt+0xca/0x1d4
> [ 420.153629] [<ffffffe0004de564>] riscv_timer_interrupt+0x32/0x3a
> [ 420.154629] [<ffffffe000612ad4>] do_IRQ+0xa4/0xb8
> [ 420.155294] [<ffffffe000036814>] ret_from_exception+0x0/0xc
> [ 420.156073] [<ffffffe000036814>] ret_from_exception+0x0/0xc

\
 
 \ /
  Last update: 2019-11-15 08:59    [W:0.125 / U:18.172 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site