Hi, masami:
I have read your post at https://lkml.org/lkml/2011/7/1/185 , which
remove the preempt disable code in kprobe.
Does it safe on arm(32) ? In my scenario I (have to) write some sleep code
which may cause reschedule in the probe handler. Then I got schedule bug
report like below:
<4>[ 369.000535] [<c0110e54>] (unwind_backtrace+0x0/0x158) from [<c0ad9724>]
(dump_stack+0x20/0x24)
<4>[ 369.000609] [<c0ad9724>] (dump_stack+0x20/0x24) from [<c0ada664>]
(__schedule_bug+0x58/0x64)
<4>[ 369.000654] [<c0ada664>] (__schedule_bug+0x58/0x64) from [<c0aec4e0>]
(__schedule+0x764/0x8e0)
<4>[ 369.000730] [<c0aec4e0>] (__schedule+0x764/0x8e0) from [<c0aec7ac>]
(schedule+0x40/0x80)
<4>[ 369.000806] [<c0aec7ac>] (schedule+0x40/0x80) from [<c0ae9bac>]
(schedule_timeout+0x230/0x3dc)
<4>[ 369.000884] [<c0ae9bac>] (schedule_timeout+0x230/0x3dc) from [<c0aebbdc>]
(wait_for_common+0x100/0x184)
<4>[ 369.000929] [<c0aebbdc>] (wait_for_common+0x100/0x184) from [<c0aebc84>]
(wait_for_completion+0x24/0x28)
<4>[ 369.001007] [<c0aebc84>] (wait_for_completion+0x24/0x28) from
[<c01c1a14>] (call_usermodehelper_exec+0x150/0x168)
<4>[ 369.001083] [<c01c1a14>] (call_usermodehelper_exec+0x150/0x168) from
[<bf0005b4>] (log_to_user.constprop.1+0x11c/0x16
The bug was triggered by call_usermodehelper with UMH_WAIT_PROC argument ,
then the schedule function will read the preempt_count. It should be 1, but
here it is 2.
Is it legal to sleep in kprobe handler? Is there is way to walkaroud this
problem?
Thanks !!
--
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/
