Re: [PATCH 0/6] locking/rwsem: Rework writer wakeup and handoff

[Waiman Long]

On 2/23/23 07:26, Peter Zijlstra wrote:
> Hi,
>
> these here few patches boot but are otherwise very much untested. Please test.

I like the unification that you have done with this series.

However, I got the following task hanging message when doing a kernel build:

[ 2215.893058]  </TASK>
[ 2215.895252] INFO: task pahole:65220 blocked for more than 123 seconds.
[ 2215.901776]       Tainted: G S         OE      6.2.0-test+ #1
[ 2215.907520] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" 
disables this message.
[ 2215.915347] task:pahole          state:D stack:0     pid:65220 
ppid:65065  flags:0x00000000
[ 2215.923690] Call Trace:
[ 2215.926146]  <TASK>
[ 2215.928250]  __schedule+0x367/0x950
[ 2215.931741]  schedule+0x50/0xc0
[ 2215.934888]  schedule_preempt_disabled+0x11/0x20
[ 2215.939507]  rwsem_down_read_slowpath+0x28c/0x520
[ 2215.944215]  down_read+0x98/0xc0
[ 2215.947446]  do_user_addr_fault+0x410/0x700
[ 2215.951633]  exc_page_fault+0x64/0x140
[ 2215.955385]  asm_exc_page_fault+0x22/0x30
[ 2215.959394] RIP: 0033:0x7f37f8808dd2
[ 2215.962974] RSP: 002b:00007ffe7bc89e80 EFLAGS: 00010246
[ 2215.968199] RAX: 00007f377d7fb000 RBX: 00007f377dffb700 RCX: 
00007f37f8439a1b
[ 2215.975332] RDX: 0000000000000003 RSI: 0000000000800000 RDI: 
00007f377d7fc000
[ 2215.982465] RBP: 00007ffe7bc89f50 R08: 00000000ffffffff R09: 
0000000000000000
[ 2215.989594] R10: 0000000000000000 R11: 0000000000000206 R12: 
0000000000001000
[ 2215.996728] R13: 00007ffe7bc89ee0 R14: 0000000000000000 R15: 
0000000000801000
[ 2216.003862]  </TASK>

I am a bit tired now. I will look at the series again tomorrow to see if 
there is something missing.

Cheers,
Longman