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Message-ID: <20160812100447.GD12939@e104818-lin.cambridge.arm.com>
Date: Fri, 12 Aug 2016 11:04:48 +0100
From: Catalin Marinas <catalin.marinas@....com>
To: Vignesh R <vigneshr@...com>
Cc: "Strashko, Grygorii" <grygorii.strashko@...com>,
"linux-mm@...ck.org" <linux-mm@...ck.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>
Subject: Re: kmemleak: Cannot insert 0xff7f1000 into the object search tree
(overlaps existing)
On Fri, Aug 12, 2016 at 09:45:05AM +0530, Vignesh R wrote:
> On Thursday 11 August 2016 10:38 PM, Catalin Marinas wrote:
> > diff --git a/mm/memblock.c b/mm/memblock.c
> > index 483197ef613f..7d3361d53ac2 100644
> > --- a/mm/memblock.c
> > +++ b/mm/memblock.c
> > @@ -723,7 +723,8 @@ int __init_memblock memblock_free(phys_addr_t base, phys_addr_t size)
> > (unsigned long long)base + size - 1,
> > (void *)_RET_IP_);
> >
> > - kmemleak_free_part(__va(base), size);
> > + if (base < __pa(high_memory))
> > + kmemleak_free_part(__va(base), size);
> > return memblock_remove_range(&memblock.reserved, base, size);
> > }
> >
> > @@ -1152,7 +1153,8 @@ static phys_addr_t __init memblock_alloc_range_nid(phys_addr_t size,
> > * The min_count is set to 0 so that memblock allocations are
> > * never reported as leaks.
> > */
> > - kmemleak_alloc(__va(found), size, 0, 0);
> > + if (found < __pa(high_memory))
> > + kmemleak_alloc(__va(found), size, 0, 0);
> > return found;
> > }
> > return 0;
> > @@ -1399,7 +1401,8 @@ void __init __memblock_free_early(phys_addr_t base, phys_addr_t size)
> > memblock_dbg("%s: [%#016llx-%#016llx] %pF\n",
> > __func__, (u64)base, (u64)base + size - 1,
> > (void *)_RET_IP_);
> > - kmemleak_free_part(__va(base), size);
> > + if (base < __pa(high_memory))
> > + kmemleak_free_part(__va(base), size);
> > memblock_remove_range(&memblock.reserved, base, size);
> > }
> >
> > @@ -1419,7 +1422,8 @@ void __init __memblock_free_late(phys_addr_t base, phys_addr_t size)
> > memblock_dbg("%s: [%#016llx-%#016llx] %pF\n",
> > __func__, (u64)base, (u64)base + size - 1,
> > (void *)_RET_IP_);
> > - kmemleak_free_part(__va(base), size);
> > + if (base < __pa(high_memory))
> > + kmemleak_free_part(__va(base), size);
> > cursor = PFN_UP(base);
> > end = PFN_DOWN(base + size);
>
> With above change on 4.8-rc1, I see a different warning from kmemleak:
>
> [ 0.002918] kmemleak: Trying to color unknown object at 0xfe800000 as
> Black
> [ 0.002943] CPU: 0 PID: 0 Comm: swapper/0 Not tainted
> 4.8.0-rc1-00121-g4b9eaf33d83d-dirty #59
> [ 0.002955] Hardware name: Generic AM33XX (Flattened Device Tree)
> [ 0.003000] [<c01100fc>] (unwind_backtrace) from [<c010c264>] (show_stack+0x10/0x14)
> [ 0.003027] [<c010c264>] (show_stack) from [<c049040c>] (dump_stack+0xac/0xe0)
> [ 0.003052] [<c049040c>] (dump_stack) from [<c02971c0>] (paint_ptr+0x78/0x9c)
> [ 0.003074] [<c02971c0>] (paint_ptr) from [<c0b25e20>] (kmemleak_init+0x1cc/0x284)
> [ 0.003104] [<c0b25e20>] (kmemleak_init) from [<c0b00bc0>] (start_kernel+0x2d8/0x3b4)
> [ 0.003122] [<c0b00bc0>] (start_kernel) from [<8000807c>] (0x8000807c)
> [ 0.003133] kmemleak: Early log backtrace:
> [ 0.003146] [<c0b3c9cc>] dma_contiguous_reserve+0x80/0x94
> [ 0.003170] [<c0b06810>] arm_memblock_init+0x130/0x184
> [ 0.003191] [<c0b04210>] setup_arch+0x58c/0xc00
> [ 0.003208] [<c0b00940>] start_kernel+0x58/0x3b4
> [ 0.003224] [<8000807c>] 0x8000807c
> [ 0.003239] [<ffffffff>] 0xffffffff
That's because I missed the CMA kmemleak call:
diff --git a/mm/cma.c b/mm/cma.c
index bd0e1412475e..7c0ef3037415 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -336,7 +336,8 @@ int __init cma_declare_contiguous(phys_addr_t base,
* kmemleak scans/reads tracked objects for pointers to other
* objects but this address isn't mapped and accessible
*/
- kmemleak_ignore(phys_to_virt(addr));
+ if (addr < __pa(high_memory))
+ kmemleak_ignore(phys_to_virt(addr));
base = addr;
}
Anyway, a better workaround is to add kmemleak_*_phys() static inline
functions and do the __pa(high_memory) check in there:
-----------------8<---------------------------
>From b8b9141fffc1fd3c73583c1fd50a724c4a6452e1 Mon Sep 17 00:00:00 2001
From: Catalin Marinas <catalin.marinas@....com>
Date: Fri, 12 Aug 2016 10:43:06 +0100
Subject: [PATCH] mm: kmemleak: Avoid using __va() on addresses that don't have
a lowmem mapping
Some of the kmemleak_*() callbacks in memblock, bootmem, CMA convert a
physical address to a virtual one using __va(). However, such physical
addresses may sometimes be located in highmem and using __va() is
incorrect, leading to inconsistent object tracking in kmemleak.
The following functions have been added to the kmemleak API and they
take a physical address as the object pointer. They only perform the
corresponding action if the address has a lowmem mapping:
kmemleak_alloc_phys
kmemleak_free_part_phys
kmemleak_not_leak_phys
kmemleak_ignore_phys
The affected calling placess have been updated to use the new kmemleak
API.
Reported-by: Vignesh R <vigneshr@...com>
Signed-off-by: Catalin Marinas <catalin.marinas@....com>
---
Documentation/kmemleak.txt | 9 +++++++++
include/linux/kmemleak.h | 26 ++++++++++++++++++++++++++
mm/bootmem.c | 6 +++---
mm/cma.c | 2 +-
mm/memblock.c | 8 ++++----
mm/nobootmem.c | 2 +-
6 files changed, 44 insertions(+), 9 deletions(-)
diff --git a/Documentation/kmemleak.txt b/Documentation/kmemleak.txt
index 18e24abb3ecf..35e1a8891e3a 100644
--- a/Documentation/kmemleak.txt
+++ b/Documentation/kmemleak.txt
@@ -155,6 +155,15 @@ kmemleak_erase - erase an old value in a pointer variable
kmemleak_alloc_recursive - as kmemleak_alloc but checks the recursiveness
kmemleak_free_recursive - as kmemleak_free but checks the recursiveness
+The following functions take a physical address as the object pointer
+and only perform the corresponding action if the address has a lowmem
+mapping:
+
+kmemleak_alloc_phys
+kmemleak_free_part_phys
+kmemleak_not_leak_phys
+kmemleak_ignore_phys
+
Dealing with false positives/negatives
--------------------------------------
diff --git a/include/linux/kmemleak.h b/include/linux/kmemleak.h
index 4894c6888bc6..380f72bc3657 100644
--- a/include/linux/kmemleak.h
+++ b/include/linux/kmemleak.h
@@ -21,6 +21,7 @@
#ifndef __KMEMLEAK_H
#define __KMEMLEAK_H
+#include <linux/mm.h>
#include <linux/slab.h>
#ifdef CONFIG_DEBUG_KMEMLEAK
@@ -109,4 +110,29 @@ static inline void kmemleak_no_scan(const void *ptr)
#endif /* CONFIG_DEBUG_KMEMLEAK */
+static inline void kmemleak_alloc_phys(phys_addr_t phys, size_t size,
+ int min_count, gfp_t gfp)
+{
+ if (!IS_ENABLED(CONFIG_HIGHMEM) || phys < __pa(high_memory))
+ kmemleak_alloc(__va(phys), size, min_count, gfp);
+}
+
+static inline void kmemleak_free_part_phys(phys_addr_t phys, size_t size)
+{
+ if (!IS_ENABLED(CONFIG_HIGHMEM) || phys < __pa(high_memory))
+ kmemleak_free_part(__va(phys), size);
+}
+
+static inline void kmemleak_not_leak_phys(phys_addr_t phys)
+{
+ if (!IS_ENABLED(CONFIG_HIGHMEM) || phys < __pa(high_memory))
+ kmemleak_not_leak(__va(phys));
+}
+
+static inline void kmemleak_ignore_phys(phys_addr_t phys)
+{
+ if (!IS_ENABLED(CONFIG_HIGHMEM) || phys < __pa(high_memory))
+ kmemleak_ignore(__va(phys));
+}
+
#endif /* __KMEMLEAK_H */
diff --git a/mm/bootmem.c b/mm/bootmem.c
index 0aa7dda52402..80f1d70bad2d 100644
--- a/mm/bootmem.c
+++ b/mm/bootmem.c
@@ -158,7 +158,7 @@ void __init free_bootmem_late(unsigned long physaddr, unsigned long size)
{
unsigned long cursor, end;
- kmemleak_free_part(__va(physaddr), size);
+ kmemleak_free_part_phys(physaddr, size);
cursor = PFN_UP(physaddr);
end = PFN_DOWN(physaddr + size);
@@ -402,7 +402,7 @@ void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
{
unsigned long start, end;
- kmemleak_free_part(__va(physaddr), size);
+ kmemleak_free_part_phys(physaddr, size);
start = PFN_UP(physaddr);
end = PFN_DOWN(physaddr + size);
@@ -423,7 +423,7 @@ void __init free_bootmem(unsigned long physaddr, unsigned long size)
{
unsigned long start, end;
- kmemleak_free_part(__va(physaddr), size);
+ kmemleak_free_part_phys(physaddr, size);
start = PFN_UP(physaddr);
end = PFN_DOWN(physaddr + size);
diff --git a/mm/cma.c b/mm/cma.c
index bd0e1412475e..384c2cb51b56 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -336,7 +336,7 @@ int __init cma_declare_contiguous(phys_addr_t base,
* kmemleak scans/reads tracked objects for pointers to other
* objects but this address isn't mapped and accessible
*/
- kmemleak_ignore(phys_to_virt(addr));
+ kmemleak_ignore_phys(addr);
base = addr;
}
diff --git a/mm/memblock.c b/mm/memblock.c
index 483197ef613f..30ecea7b45d1 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -723,7 +723,7 @@ int __init_memblock memblock_free(phys_addr_t base, phys_addr_t size)
(unsigned long long)base + size - 1,
(void *)_RET_IP_);
- kmemleak_free_part(__va(base), size);
+ kmemleak_free_part_phys(base, size);
return memblock_remove_range(&memblock.reserved, base, size);
}
@@ -1152,7 +1152,7 @@ static phys_addr_t __init memblock_alloc_range_nid(phys_addr_t size,
* The min_count is set to 0 so that memblock allocations are
* never reported as leaks.
*/
- kmemleak_alloc(__va(found), size, 0, 0);
+ kmemleak_alloc_phys(found, size, 0, 0);
return found;
}
return 0;
@@ -1399,7 +1399,7 @@ void __init __memblock_free_early(phys_addr_t base, phys_addr_t size)
memblock_dbg("%s: [%#016llx-%#016llx] %pF\n",
__func__, (u64)base, (u64)base + size - 1,
(void *)_RET_IP_);
- kmemleak_free_part(__va(base), size);
+ kmemleak_free_part_phys(base, size);
memblock_remove_range(&memblock.reserved, base, size);
}
@@ -1419,7 +1419,7 @@ void __init __memblock_free_late(phys_addr_t base, phys_addr_t size)
memblock_dbg("%s: [%#016llx-%#016llx] %pF\n",
__func__, (u64)base, (u64)base + size - 1,
(void *)_RET_IP_);
- kmemleak_free_part(__va(base), size);
+ kmemleak_free_part_phys(base, size);
cursor = PFN_UP(base);
end = PFN_DOWN(base + size);
diff --git a/mm/nobootmem.c b/mm/nobootmem.c
index bd05a70f44b9..a056d31dff7e 100644
--- a/mm/nobootmem.c
+++ b/mm/nobootmem.c
@@ -81,7 +81,7 @@ void __init free_bootmem_late(unsigned long addr, unsigned long size)
{
unsigned long cursor, end;
- kmemleak_free_part(__va(addr), size);
+ kmemleak_free_part_phys(addr, size);
cursor = PFN_UP(addr);
end = PFN_DOWN(addr + size);
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