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SubjectRe: [PATCH 2/3] mm/vmalloc: do not call kmemleak_free() on not yet accounted memory
On 2019-01-11 20:26, Andrey Ryabinin wrote:
> On 1/3/19 5:59 PM, Roman Penyaev wrote:
>> __vmalloc_area_node() calls vfree() on error path, which in turn calls
>> kmemleak_free(), but area is not yet accounted by kmemleak_vmalloc().
>>
>> Signed-off-by: Roman Penyaev <rpenyaev@suse.de>
>> Cc: Andrew Morton <akpm@linux-foundation.org>
>> Cc: Michal Hocko <mhocko@suse.com>
>> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
>> Cc: Joe Perches <joe@perches.com>
>> Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>
>> Cc: linux-mm@kvack.org
>> Cc: linux-kernel@vger.kernel.org
>> ---
>> mm/vmalloc.c | 16 +++++++++++-----
>> 1 file changed, 11 insertions(+), 5 deletions(-)
>>
>> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
>> index 2cd24186ba84..dc6a62bca503 100644
>> --- a/mm/vmalloc.c
>> +++ b/mm/vmalloc.c
>> @@ -1565,6 +1565,14 @@ void vfree_atomic(const void *addr)
>> __vfree_deferred(addr);
>> }
>>
>> +static void __vfree(const void *addr)
>> +{
>> + if (unlikely(in_interrupt()))
>> + __vfree_deferred(addr);
>> + else
>> + __vunmap(addr, 1);
>> +}
>> +
>> /**
>> * vfree - release memory allocated by vmalloc()
>> * @addr: memory base address
>> @@ -1591,10 +1599,8 @@ void vfree(const void *addr)
>>
>> if (!addr)
>> return;
>> - if (unlikely(in_interrupt()))
>> - __vfree_deferred(addr);
>> - else
>> - __vunmap(addr, 1);
>> +
>> + __vfree(addr);
>> }
>> EXPORT_SYMBOL(vfree);
>>
>> @@ -1709,7 +1715,7 @@ static void *__vmalloc_area_node(struct
>> vm_struct *area, gfp_t gfp_mask,
>> warn_alloc(gfp_mask, NULL,
>> "vmalloc: allocation failure, allocated %ld of %ld bytes",
>> (area->nr_pages*PAGE_SIZE), area->size);
>> - vfree(area->addr);
>> + __vfree(area->addr);
>
> This can't be an interrupt context for a several reasons. One of them
> is BUG_ON(in_interrupt()) in __get_vm_area_node()
> which is called right before __vmalloc_are_node().
>
> So you can just do __vunmap(area->addr, 1); instead of __vfree().

Thanks, I missed that BUG_ON and could not prove, that we can call only
from a task context, thus decided not to make it strict. Of course
simple __vunmap() is much better. The other reason is that we call a
spin_lock without disabling the interrupts. Now I see.

Andrew, may I resend just an updated version of this patch?

--
Roman

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