From: Steven Rostedt <rostedt@goodmis.org>
To: Fengguang Wu <fengguang.wu@intel.com>
Cc: LKP <lkp@01.org>, linux-kernel@vger.kernel.org
Subject: Re: [ftrace/fgraph/x86] BUG: unable to handle kernel paging request at 3d00c17d
Date: Wed, 10 Dec 2014 23:09:13 -0500 [thread overview]
Message-ID: <20141210230913.0bcbb124@gandalf.local.home> (raw)
In-Reply-To: <20141210231732.GA24163@wfg-t540p.sh.intel.com>
On Wed, 10 Dec 2014 15:17:32 -0800
Fengguang Wu <fengguang.wu@intel.com> wrote:
> Hi Steven,
>
> 0day kernel testing robot got the below dmesg and the first bad commit is
>
> git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> commit 6a06bdbf7f9c669743f58084991ba280f2925586
> Author: Steven Rostedt (Red Hat) <rostedt@goodmis.org>
> AuthorDate: Mon Nov 24 21:00:34 2014 -0500
> Commit: Steven Rostedt <rostedt@goodmis.org>
> CommitDate: Mon Dec 1 14:08:58 2014 -0500
>
> ftrace/fgraph/x86: Have prepare_ftrace_return() take ip as first parameter
>
> The function graph helper function prepare_ftrace_return() which does the work
> to hijack the parent pointer has that parent pointer as its first parameter.
> Instead, if we make it the second parameter and have ip as the first parameter
> (self_addr), then it can use the %rdi from save_mcount_regs that loads it
> already.
>
> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1411262304010.3961@nanos
>
> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Crap! Yeah, I was wondering how this could be the bug, but then I
realized this was i386 not x86_64 and I never updated the i386 call to
prepare_ftrace_return().
Does this patch fix it?
-- Steve
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index b553ed89e5f5..df3e608d409b 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -1192,10 +1192,10 @@ ENTRY(ftrace_graph_caller)
pushl %eax
pushl %ecx
pushl %edx
- movl 0xc(%esp), %edx
- lea 0x4(%ebp), %eax
+ movl 0xc(%esp), %eax
+ lea 0x4(%ebp), %edx
movl (%ebp), %ecx
- subl $MCOUNT_INSN_SIZE, %edx
+ subl $MCOUNT_INSN_SIZE, %eax
call prepare_ftrace_return
popl %edx
popl %ecx
next prev parent reply other threads:[~2014-12-11 4:09 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-10 23:17 Fengguang Wu
2014-12-10 23:19 ` [ftrace/fgraph/x86] BUG: unable to handle kernel paging request at c0017eec Fengguang Wu
2014-12-11 4:09 ` Steven Rostedt [this message]
2014-12-11 21:42 ` [ftrace/fgraph/x86] BUG: unable to handle kernel paging request at 3d00c17d Fengguang Wu
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