Messages in this thread Patch in this message | | | Subject | Re: Redundant up operation in stop_machine.c ?(2.6.12) | From | Rusty Russell <> | Date | Fri, 26 Aug 2005 12:08:22 +1000 |
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On Thu, 2005-08-25 at 21:59 +0800, Yingchao Zhou wrote: > In stop_machine function, there are codes: > if (ret < 0) { > stopmachine_set_state(STOPMACHINE_EXIT); > up(&stopmachine_mutex); > return ret; > } > And in __stop_machine_run ,there are: > if (!IS_ERR(p)) { > kthread_bind(p, cpu); > wake_up_process(p); > wait_for_completion(&smdata.done); > } > up(&stopmachine_mutex); > > Is the first up op is really redundant?
Yes, it seems you have found a bug. I tested it (inserting a spurious failure), and indeed, it gets up'ed twice.
Good catch! Rusty.
Name: Redundant up operation in stop_machine.c Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (authored)
Yingchao Zhou <puppylove_0814@yahoo.com.cn> noticed that we up() in stop_machine on failure, and also in the caller (unconditionally).
Index: linux-2.6.13-rc7-git1-Misc/kernel/stop_machine.c =================================================================== --- linux-2.6.13-rc7-git1-Misc.orig/kernel/stop_machine.c 2005-08-26 11:18:00.000000000 +1000 +++ linux-2.6.13-rc7-git1-Misc/kernel/stop_machine.c 2005-08-26 12:05:01.000000000 +1000 @@ -115,7 +115,6 @@ /* If some failed, kill them all. */ if (ret < 0) { stopmachine_set_state(STOPMACHINE_EXIT); - up(&stopmachine_mutex); return ret; } -- A bad analogy is like a leaky screwdriver -- Richard Braakman
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