Messages in this thread Patch in this message | | | Date | Sat, 24 Jun 2006 11:55:26 +0100 | From | "Catalin Marinas" <> | Subject | Re: [PATCH 2.6.17-rc6 7/9] Remove some of the kmemleak false positives |
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On 24/06/06, Ingo Molnar <mingo@elte.hu> wrote: > > * Catalin Marinas <catalin.marinas@gmail.com> wrote: > > To the other extreme is Ingo's suggestion of using exact type > > identification but I don't think this would be acceptable for the > > kernel as it would to modify all the memory alloc calls in the kernel > > to either pass an additional parameter (the type id) or another > > post-allocation call to kmemleak to update the id. > > passing in the type ID wouldnt be that bad and it would have other > advantages as well: for example we could do strict type-checking of > allocation size versus type-we-use-it-for.
There are valid places in the kernel where the allocated size is different from the type's one. That's why I added the memleak_padding().
> As long as the conversion is gradual i think we could try this. I.e. > we'd default to 'no ID passed', and in that case we would fall back to > the size-based method and generate an ID out of the structure size.
OK, I'll try to add the infrastructure for type ids but default to sizeof initially.
> > Anyway, the current implementation (I'll update it for 2.6.17) detects > > real memory leaks. I suspect that a wide range of leaks would be > > covered if it is used on different platforms and different conditions. > > btw., what leaks were found so far? I know about the ACPI one - any > other ones?
There are two leaks reported in ACPI but I only posted a patch for one as I didn't have time to track the other (a reference count doesn't get to zero and the structure not freed).
There is another leak in legacy_init_iomem_resources() in arch/i386/setup.c (request_resource() fails but the memory is not freed - see the attached patch). I initially marked this as a false positive but it wasn't (I have to revisit the false positives).
-- Catalin Fix a memory leak in the i386 setup code
From: Catalin Marinas <catalin.marinas@gmail.com>
Signed-off-by: Catalin Marinas <catalin.marinas@gmail.com> ---
arch/i386/kernel/setup.c | 5 ++++- 1 files changed, 4 insertions(+), 1 deletions(-)
diff --git a/arch/i386/kernel/setup.c b/arch/i386/kernel/setup.c index dd6b0e3..60f5d99 100644 --- a/arch/i386/kernel/setup.c +++ b/arch/i386/kernel/setup.c @@ -1332,7 +1332,10 @@ legacy_init_iomem_resources(struct resou res->start = e820.map[i].addr; res->end = res->start + e820.map[i].size - 1; res->flags = IORESOURCE_MEM | IORESOURCE_BUSY; - request_resource(&iomem_resource, res); + if (request_resource(&iomem_resource, res)) { + kfree(res); + continue; + } if (e820.map[i].type == E820_RAM) { /* * We don't know which RAM region contains kernel data, | |