lkml.org 
[lkml]   [2011]   [Oct]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Subjectkdump: crash_kexec()-smp_send_stop() race in panic
From
Date
Hello Vivek,

In our tests we ran into the following scenario:

Two CPUs have called panic at the same time. The first CPU called
crash_kexec() and the second CPU called smp_send_stop() in panic()
before crash_kexec() finished on the first CPU. So the second CPU
stopped the first CPU and therefore kdump failed.

1st CPU:
panic()->crash_kexec()->mutex_trylock(&kexec_mutex)-> do kdump

2nd CPU:
panic()->crash_kexec()->kexec_mutex already held by 1st CPU
->smp_send_stop()-> stop CPU 1 (stop kdump)

How should we fix this problem? One possibility could be to do
smp_send_stop() before we call crash_kexec().

What do you think?

Michael




\
 
 \ /
  Last update: 2011-10-24 16:57    [W:0.062 / U:0.264 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site