Re: [PATCH 6/6] mm: Postpone the disabling of kmemleak early logging

[Catalin Marinas <catalin.marinas@arm.com>]

On Tue, May 06, 2014 at 04:20:27PM +0100, Sasha Levin wrote:
> On 05/02/2014 09:41 AM, Catalin Marinas wrote:
> > Currently, kmemleak_early_log is disabled at the beginning of the
> > kmemleak_init() function, before the full kmemleak tracing is actually
> > enabled. In this small window, kmem_cache_create() is called by kmemleak
> > which triggers additional memory allocation that are not traced. This
> > patch moves the kmemleak_early_log disabling further down and at the
> > same time with full kmemleak enabling.
> > 
> > Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
> > Cc: Andrew Morton <akpm@linux-foundation.org>
> 
> This patch makes the kernel die during the boot process:
> 
> [   24.471801] BUG: unable to handle kernel paging request at ffffffff922f2b93
> [   24.472496] IP: [<ffffffff922f2b93>] log_early+0x0/0xcd

Thanks for reporting this. I assume you run with
CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF enabled and kmemleak_early_log remains
set even though kmemleak is not in use.

Does the patch below fix it?

diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 0cd6aabd45a0..e7f74091c024 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -1811,6 +1811,7 @@ void __init kmemleak_init(void)
 
 #ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF
 	if (!kmemleak_skip_disable) {
+		kmemleak_early_log = 0;
 		kmemleak_disable();
 		return;
 	}

Thanks.

-- 
Catalin

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