Messages in this thread Patch in this message | | | Date | Tue, 12 Sep 2006 18:54:48 +0200 | From | Ingo Molnar <> | Subject | Re: lockdep warning in check_flags() |
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* Frederik Deweerdt <deweerdt@free.fr> wrote:
> On Mon, Sep 11, 2006 at 07:43:35AM +0200, Ingo Molnar wrote: > > > > * Frederik Deweerdt <deweerdt@free.fr> wrote: > > > > > Lockdep issues the following warning: > > > > > > [ 16.835268] Freeing unused kernel memory: 260k freed > > > [ 16.842715] Write protecting the kernel read-only data: 432k > > > [ 17.796518] BUG: warning at kernel/lockdep.c:2359/check_flags() > > > > this warning means that the "soft" and "hard" hardirqs-disabled state > > got out of sync: the irqtrace tracking code thinks that hardirqs are > > disabled, while in reality they are enabled. The thing to watch for are > > new "stii" instructions in entry.S (and other assembly code), without a > > matching TRACE_HARDIRQS_ON call. [Another, rarer possiblity is NMI code > > saving/restoring interrupts - do you have NMIs enabled? (are there any > > NMI counts in /proc/interrupts?)] > NMIs were disabled. But I've just booted -mm2 and the warning went away. > Could this be related to the recent pda changes?
yeah, it could be related to the fix below. Can you confirm that by applying this to your -mm1 tree the message goes away?
Ingo
---------------> Subject: [patch] i386-PDA, lockdep: fix %gs restore From: Ingo Molnar <mingo@elte.hu>
in the syscall exit path the %gs selector has to be restored _after_ the last kernel function has been called. If lockdep is enabled then this kernel function is TRACE_IRQS_ON.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
--- arch/i386/kernel/entry.S | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
Index: linux/arch/i386/kernel/entry.S =================================================================== --- linux.orig/arch/i386/kernel/entry.S +++ linux/arch/i386/kernel/entry.S @@ -326,11 +326,12 @@ sysenter_past_esp: testw $_TIF_ALLWORK_MASK, %cx jne syscall_exit_work /* if something modifies registers it must also disable sysexit */ -1: mov PT_GS(%esp), %gs +1: + TRACE_IRQS_ON + mov PT_GS(%esp), %gs movl PT_EIP(%esp), %edx movl PT_OLDESP(%esp), %ecx xorl %ebp,%ebp - TRACE_IRQS_ON ENABLE_INTERRUPTS_SYSEXIT CFI_ENDPROC .pushsection .fixup,"ax"; \ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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