Messages in this thread Patch in this message | | | Date | Wed, 10 Dec 2014 23:09:13 -0500 | From | Steven Rostedt <> | Subject | Re: [ftrace/fgraph/x86] BUG: unable to handle kernel paging request at 3d00c17d |
| |
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
| |