Messages in this thread | | | Date | Thu, 11 Dec 2014 13:42:02 -0800 | From | Fengguang Wu <> | Subject | Re: [ftrace/fgraph/x86] BUG: unable to handle kernel paging request at 3d00c17d |
| |
Hi Steven,
On Wed, Dec 10, 2014 at 11:09:13PM -0500, Steven Rostedt wrote: > 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?
Yes, it fixed the issue.
Tested-by: Fengguang Wu <fengguang.wu@intel.com>
Thanks, Fengguang
> > 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
| |