Messages in this thread Patch in this message | | | Date | Mon, 26 Sep 2011 17:50:24 +0100 | From | Catalin Marinas <> | Subject | Re: Question about memory leak detector giving false positive report for net/core/flow.c |
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On Mon, Sep 26, 2011 at 05:32:54PM +0100, Eric Dumazet wrote: > Le lundi 26 septembre 2011 à 23:17 +0800, Huajun Li a écrit : > > Memory leak detector gives following memory leak report, it seems the > > report is triggered by net/core/flow.c, but actually, it should be a > > false positive report. > > So, is there any idea from kmemleak side to fix/disable this false > > positive report like this? > > Yes, kmemleak_not_leak(...) could disable it, but is it suitable for this case ? ... > CC lkml and percpu maintainers (Tejun Heo & Christoph Lameter ) as well > > AFAIK this false positive only occurs if percpu data is allocated > outside of embedded pcu space. > > (grep pcpu_get_vm_areas /proc/vmallocinfo) > > I suspect this is a percpu/kmemleak cooperation problem (a missing > kmemleak_alloc() ?) > > I am pretty sure kmemleak_not_leak() is not the right answer to this > problem.
kmemleak_not_leak() definitely not the write answer. The alloc_percpu() call does not have any kmemleak_alloc() callback, so it doesn't scan them.
Huajun, could you please try the patch below:
8<-------------------------------- kmemleak: Handle percpu memory allocation
From: Catalin Marinas <catalin.marinas@arm.com>
This patch adds kmemleak callbacks from the percpu allocator, reducing a number of false positives caused by kmemleak not scanning such memory blocks.
Reported-by: Huajun Li <huajun.li.lee@gmail.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> --- mm/percpu.c | 11 +++++++++-- 1 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/mm/percpu.c b/mm/percpu.c index bf80e55..c47a90b 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -67,6 +67,7 @@ #include <linux/spinlock.h> #include <linux/vmalloc.h> #include <linux/workqueue.h> +#include <linux/kmemleak.h> #include <asm/cacheflush.h> #include <asm/sections.h> @@ -833,7 +834,9 @@ fail_unlock_mutex: */ void __percpu *__alloc_percpu(size_t size, size_t align) { - return pcpu_alloc(size, align, false); + void __percpu *ptr = pcpu_alloc(size, align, false); + kmemleak_alloc(ptr, size, 1, GFP_KERNEL); + return ptr; } EXPORT_SYMBOL_GPL(__alloc_percpu); @@ -855,7 +858,9 @@ EXPORT_SYMBOL_GPL(__alloc_percpu); */ void __percpu *__alloc_reserved_percpu(size_t size, size_t align) { - return pcpu_alloc(size, align, true); + void __percpu *ptr = pcpu_alloc(size, align, true); + kmemleak_alloc(ptr, size, 1, GFP_KERNEL); + return ptr; } /** @@ -915,6 +920,8 @@ void free_percpu(void __percpu *ptr) if (!ptr) return; + kmemleak_free(ptr); + addr = __pcpu_ptr_to_addr(ptr); spin_lock_irqsave(&pcpu_lock, flags); -- Catalin -- 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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