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From: "wcohen at redhat dot com" <sourceware-bugzilla@sourceware.org>
To: systemtap@sourceware.org
Subject: [Bug runtime/31074] On aarch64 the systemtap.base/set_kernel.stp triggers "Unable to handle kernel paging request"
Date: Mon, 27 Nov 2023 16:07:56 +0000	[thread overview]
Message-ID: <bug-31074-6586-j7ruB3fytp@http.sourceware.org/bugzilla/> (raw)
In-Reply-To: <bug-31074-6586@http.sourceware.org/bugzilla/>

https://sourceware.org/bugzilla/show_bug.cgi?id=31074

--- Comment #4 from William Cohen <wcohen at redhat dot com> ---
Looking a bit more at the stp_tracepoint.c code.  If e was NULL for
hlist_for_each_entry should, it should exit the for loop rather than doing the
strcmp:

https://elixir.bootlin.com/linux/v6.5.11/source/include/linux/list.h#L1053

The problem attemtped access is occurring when tracepoints are being removed. 
It is a bit surprising the that the similar code in add_tracepoint doesn't
encounter a similar problem earlier around with virtually identical code in
add_tracepoint:

https://sourceware.org/git/?p=systemtap.git;a=blob;f=runtime/linux/stp_tracepoint.c;h=508948dce4fd438bde6d9d155035faba2abd0ee1;hb=HEAD#l146



The suggested patch isn't making much sense to me. 

e is a local variable that would no longer be initialized before the
"if(!e){..." check.

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  parent reply	other threads:[~2023-11-27 16:07 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-17 17:13 [Bug runtime/31074] New: " wcohen at redhat dot com
2023-11-22  0:19 ` [Bug runtime/31074] " fche at redhat dot com
2023-11-22 15:02 ` wcohen at redhat dot com
2023-11-22 15:36 ` fche at redhat dot com
2023-11-27 16:07 ` wcohen at redhat dot com [this message]
2023-12-01 14:51 ` wcohen at redhat dot com
2023-12-01 16:45 ` wcohen at redhat dot com
2023-12-01 17:19 ` mark at klomp dot org
2023-12-04 16:38 ` wcohen at redhat dot com

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