2013-10-25 21:01:09

by Azat Khuzhin

Subject: kprobe: "BUG: unable to handle kernel paging request"

With some kernel's configuration there is such messages in dmesg in
different places while using kprobes.

I investigated this and founded that it reproduced with
https://gist.github.com/azat/7078890#file-config-3-12-0-rc5-deb
And not reproduced with
https://gist.github.com/azat/7078890#file-config-3-12-0-rc5-worked-kprobe

I used the next script for testing
https://gist.github.com/azat/7078890#file-ktap-sh

Here is the initial email log with Jovi (ktap author):
http://www.freelists.org/post/ktap/BUG-unable-to-handle-kernel-paging-request-after-ktap-script-to-trace-SyS-write

If I can help, please let me know!
Thanks!

--
Respectfully
Azat Khuzhin

2013-10-26 16:38:32

by Azat Khuzhin

Subject: Re: kprobe: "BUG: unable to handle kernel paging request"

On Sat, Oct 26, 2013 at 1:01 AM, Azat Khuzhin <[email protected]> wrote:
> With some kernel's configuration there is such messages in dmesg in
> different places while using kprobes.
>
> I investigated this and founded that it reproduced with
> https://gist.github.com/azat/7078890#file-config-3-12-0-rc5-deb
> And not reproduced with
> https://gist.github.com/azat/7078890#file-config-3-12-0-rc5-worked-kprobe

I reduced difference between this two configs,
and the new one with not worked kprobe is here:
https://gist.github.com/azat/7078890#file-config-3-12-0-rc5-dont-worked-kprobe

The only thing I changed in "make menuconfig" is preemption model,
from CONFIG_PREEMPT_VOLUNTARY(good) to CONFIG_PREEMPT(bad)

U=https://gist.github.com/azat/7078890/raw/
diff -u0 <(curl -s
$U/8268502680c9b1c5924ce6bf45dd08381bc9ddb3/config-3.12.0-rc5%2Bdont-worked-kprobe)
<(curl -s $U/b7a9367506fa1c9598f5752c045cff582c3588ba/config-3.12.0-rc5%2Bworked-kprobe)

--- /dev/fd/63 2013-10-26 20:35:00.679801733 +0400
+++ /dev/fd/62 2013-10-26 20:35:00.679801733 +0400
@@ -128,2 +128,2 @@
-CONFIG_TREE_PREEMPT_RCU=y
-CONFIG_PREEMPT_RCU=y
+CONFIG_TREE_RCU=y
+# CONFIG_PREEMPT_RCU is not set
@@ -137 +136,0 @@
-# CONFIG_RCU_BOOST is not set
@@ -224,0 +224 @@
+CONFIG_OPTPROBES=y
@@ -332 +332,5 @@
-CONFIG_UNINLINE_SPIN_UNLOCK=y
+CONFIG_INLINE_SPIN_UNLOCK_IRQ=y
+CONFIG_INLINE_READ_UNLOCK=y
+CONFIG_INLINE_READ_UNLOCK_IRQ=y
+CONFIG_INLINE_WRITE_UNLOCK=y
+CONFIG_INLINE_WRITE_UNLOCK_IRQ=y
@@ -378,2 +382,2 @@
-# CONFIG_PREEMPT_VOLUNTARY is not set
-CONFIG_PREEMPT=y
+CONFIG_PREEMPT_VOLUNTARY=y
+# CONFIG_PREEMPT is not set
@@ -3547,0 +3552 @@
+# CONFIG_DRM_I810 is not set
@@ -5047 +5051,0 @@
-CONFIG_DEBUG_PREEMPT=y
@@ -5075 +5078,0 @@
-# CONFIG_PROVE_RCU_DELAY is not set
@@ -5079 +5081,0 @@
-CONFIG_RCU_CPU_STALL_VERBOSE=y
@@ -5111 +5112,0 @@
-# CONFIG_PREEMPT_TRACER is not set

>
> I used the next script for testing
> https://gist.github.com/azat/7078890#file-ktap-sh
>
> Here is the initial email log with Jovi (ktap author):
> http://www.freelists.org/post/ktap/BUG-unable-to-handle-kernel-paging-request-after-ktap-script-to-trace-SyS-write
>
> If I can help, please let me know!
> Thanks!
>
> --
> Respectfully
> Azat Khuzhin



--
Respectfully
Azat Khuzhin