* [PATCH 1/2] mm: vmalloc: Avoid a double lookup of freed VA in a tree
@ 2022-12-20 18:27 Uladzislau Rezki (Sony)
2022-12-20 18:27 ` [PATCH 2/2] mm: vmalloc: Replace BUG_ON() by WARN_ON_ONCE() Uladzislau Rezki (Sony)
2022-12-20 18:45 ` [PATCH 1/2] mm: vmalloc: Avoid a double lookup of freed VA in a tree Uladzislau Rezki
0 siblings, 2 replies; 8+ messages in thread
From: Uladzislau Rezki (Sony) @ 2022-12-20 18:27 UTC (permalink / raw)
To: Andrew Morton
Cc: linux-mm, LKML, Baoquan He, Christoph Hellwig, Matthew Wilcox,
Nicholas Piggin, Uladzislau Rezki, Oleksiy Avramchenko
When a VA is freed over a main path, for example by invoking
the vfree() function, a tree is accessed two times what is odd:
vfree():
__vunmap()
__find_vmap_area()
vm_remove_mappings()
remove_vm_area()
__find_vmap_area()
__find_vmap_area() are called two times. Fix it by introducing
a find_unlink_vmap_area() helper that finds and un-links a VA
from a tree.
Performance test results on a single CPU:
- fix_size_alloc_test loops: 1000000 avg: 476847 usec
- full_fit_alloc_test loops: 1000000 avg: 806746 usec
- long_busy_list_alloc_test loops: 1000000 avg: 13552093 usec
- random_size_alloc_test loops: 1000000 avg: 7441322 usec
- fix_align_alloc_test loops: 1000000 avg: 1411132 usec
All test took worker0=87650866284 cycles
- fix_size_alloc_test loops: 1000000 avg: 490713 usec
- full_fit_alloc_test loops: 1000000 avg: 579162 usec
- long_busy_list_alloc_test loops: 1000000 avg: 10485448 usec
- random_size_alloc_test loops: 1000000 avg: 5824449 usec
- fix_align_alloc_test loops: 1000000 avg: 984735 usec
All test took worker0=67952362802 cycles
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
---
mm/vmalloc.c | 40 ++++++++++++++++++++++++++++------------
1 file changed, 28 insertions(+), 12 deletions(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 9e30f0b39203..0fc38c36e0df 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1825,9 +1825,14 @@ static void free_vmap_area_noflush(struct vmap_area *va)
unsigned long va_start = va->va_start;
unsigned long nr_lazy;
- spin_lock(&vmap_area_lock);
- unlink_va(va, &vmap_area_root);
- spin_unlock(&vmap_area_lock);
+ /*
+ * A free_vmap_block() is left. It is NOT a main free path.
+ */
+ if (!list_empty(&va->list)) {
+ spin_lock(&vmap_area_lock);
+ unlink_va(va, &vmap_area_root);
+ spin_unlock(&vmap_area_lock);
+ }
nr_lazy = atomic_long_add_return((va->va_end - va->va_start) >>
PAGE_SHIFT, &vmap_lazy_nr);
@@ -1871,6 +1876,19 @@ struct vmap_area *find_vmap_area(unsigned long addr)
return va;
}
+static struct vmap_area *find_unlink_vmap_area(unsigned long addr)
+{
+ struct vmap_area *va;
+
+ spin_lock(&vmap_area_lock);
+ va = __find_vmap_area(addr, &vmap_area_root);
+ if (va)
+ unlink_va(va, &vmap_area_root);
+ spin_unlock(&vmap_area_lock);
+
+ return va;
+}
+
/*** Per cpu kva allocator ***/
/*
@@ -2236,7 +2254,7 @@ void vm_unmap_ram(const void *mem, unsigned int count)
return;
}
- va = find_vmap_area(addr);
+ va = find_unlink_vmap_area(addr);
BUG_ON(!va);
debug_check_no_locks_freed((void *)va->va_start,
(va->va_end - va->va_start));
@@ -2607,21 +2625,16 @@ struct vm_struct *remove_vm_area(const void *addr)
might_sleep();
- spin_lock(&vmap_area_lock);
- va = __find_vmap_area((unsigned long)addr, &vmap_area_root);
- if (va && va->vm) {
+ va = find_unlink_vmap_area((unsigned long) addr);
+ if (va) {
struct vm_struct *vm = va->vm;
- va->vm = NULL;
- spin_unlock(&vmap_area_lock);
-
kasan_free_module_shadow(vm);
free_unmap_vmap_area(va);
return vm;
}
- spin_unlock(&vmap_area_lock);
return NULL;
}
@@ -2690,6 +2703,7 @@ static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages)
static void __vunmap(const void *addr, int deallocate_pages)
{
struct vm_struct *area;
+ struct vmap_area *va;
if (!addr)
return;
@@ -2698,7 +2712,9 @@ static void __vunmap(const void *addr, int deallocate_pages)
addr))
return;
- area = find_vm_area(addr);
+ va = find_unlink_vmap_area((unsigned long)addr);
+ area = va->vm;
+
if (unlikely(!area)) {
WARN(1, KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n",
addr);
--
2.30.2
^ permalink raw reply related [flat|nested] 8+ messages in thread* [PATCH 2/2] mm: vmalloc: Replace BUG_ON() by WARN_ON_ONCE()
2022-12-20 18:27 [PATCH 1/2] mm: vmalloc: Avoid a double lookup of freed VA in a tree Uladzislau Rezki (Sony)
@ 2022-12-20 18:27 ` Uladzislau Rezki (Sony)
2022-12-20 18:45 ` Uladzislau Rezki
2022-12-20 18:53 ` Lorenzo Stoakes
2022-12-20 18:45 ` [PATCH 1/2] mm: vmalloc: Avoid a double lookup of freed VA in a tree Uladzislau Rezki
1 sibling, 2 replies; 8+ messages in thread
From: Uladzislau Rezki (Sony) @ 2022-12-20 18:27 UTC (permalink / raw)
To: Andrew Morton
Cc: linux-mm, LKML, Baoquan He, Christoph Hellwig, Matthew Wilcox,
Nicholas Piggin, Uladzislau Rezki, Oleksiy Avramchenko
Currently a vm_unmap_ram() functions triggers a BUG() if an area
is not found. Replace it by the WARN_ON_ONCE() error message and
keep machine alive instead of stopping it.
The worst case is a memory leaking.
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
---
mm/vmalloc.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 0fc38c36e0df..e05a0dc79ac5 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2255,10 +2255,12 @@ void vm_unmap_ram(const void *mem, unsigned int count)
}
va = find_unlink_vmap_area(addr);
- BUG_ON(!va);
- debug_check_no_locks_freed((void *)va->va_start,
- (va->va_end - va->va_start));
- free_unmap_vmap_area(va);
+
+ if (!WARN_ON_ONCE(!va)) {
+ debug_check_no_locks_freed((void *)va->va_start,
+ (va->va_end - va->va_start));
+ free_unmap_vmap_area(va);
+ }
}
EXPORT_SYMBOL(vm_unmap_ram);
--
2.30.2
^ permalink raw reply related [flat|nested] 8+ messages in thread* Re: [PATCH 2/2] mm: vmalloc: Replace BUG_ON() by WARN_ON_ONCE()
2022-12-20 18:27 ` [PATCH 2/2] mm: vmalloc: Replace BUG_ON() by WARN_ON_ONCE() Uladzislau Rezki (Sony)
@ 2022-12-20 18:45 ` Uladzislau Rezki
2022-12-20 18:53 ` Lorenzo Stoakes
1 sibling, 0 replies; 8+ messages in thread
From: Uladzislau Rezki @ 2022-12-20 18:45 UTC (permalink / raw)
To: Andrew Morton
Cc: Andrew Morton, linux-mm, LKML, Baoquan He, Christoph Hellwig,
Matthew Wilcox, Nicholas Piggin, Oleksiy Avramchenko
On Tue, Dec 20, 2022 at 07:27:04PM +0100, Uladzislau Rezki (Sony) wrote:
> Currently a vm_unmap_ram() functions triggers a BUG() if an area
> is not found. Replace it by the WARN_ON_ONCE() error message and
> keep machine alive instead of stopping it.
>
> The worst case is a memory leaking.
>
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
> ---
> mm/vmalloc.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 0fc38c36e0df..e05a0dc79ac5 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -2255,10 +2255,12 @@ void vm_unmap_ram(const void *mem, unsigned int count)
> }
>
> va = find_unlink_vmap_area(addr);
> - BUG_ON(!va);
> - debug_check_no_locks_freed((void *)va->va_start,
> - (va->va_end - va->va_start));
> - free_unmap_vmap_area(va);
> +
> + if (!WARN_ON_ONCE(!va)) {
> + debug_check_no_locks_freed((void *)va->va_start,
> + (va->va_end - va->va_start));
> + free_unmap_vmap_area(va);
> + }
> }
> EXPORT_SYMBOL(vm_unmap_ram);
>
> --
> 2.30.2
>
Will send a v2.
--
Uladzislau Rezki
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH 2/2] mm: vmalloc: Replace BUG_ON() by WARN_ON_ONCE()
2022-12-20 18:27 ` [PATCH 2/2] mm: vmalloc: Replace BUG_ON() by WARN_ON_ONCE() Uladzislau Rezki (Sony)
2022-12-20 18:45 ` Uladzislau Rezki
@ 2022-12-20 18:53 ` Lorenzo Stoakes
2022-12-20 18:56 ` Lorenzo Stoakes
1 sibling, 1 reply; 8+ messages in thread
From: Lorenzo Stoakes @ 2022-12-20 18:53 UTC (permalink / raw)
To: Uladzislau Rezki (Sony)
Cc: Andrew Morton, linux-mm, LKML, Baoquan He, Christoph Hellwig,
Matthew Wilcox, Nicholas Piggin, Oleksiy Avramchenko
On Tue, Dec 20, 2022 at 07:27:04PM +0100, Uladzislau Rezki (Sony) wrote:
> Currently a vm_unmap_ram() functions triggers a BUG() if an area
> is not found. Replace it by the WARN_ON_ONCE() error message and
> keep machine alive instead of stopping it.
>
> The worst case is a memory leaking.
>
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
> ---
> mm/vmalloc.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 0fc38c36e0df..e05a0dc79ac5 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -2255,10 +2255,12 @@ void vm_unmap_ram(const void *mem, unsigned int count)
> }
>
> va = find_unlink_vmap_area(addr);
> - BUG_ON(!va);
> - debug_check_no_locks_freed((void *)va->va_start,
> - (va->va_end - va->va_start));
> - free_unmap_vmap_area(va);
> +
> + if (!WARN_ON_ONCE(!va)) {
> + debug_check_no_locks_freed((void *)va->va_start,
> + (va->va_end - va->va_start));
> + free_unmap_vmap_area(va);
> + }
> }
> EXPORT_SYMBOL(vm_unmap_ram);
>
> --
> 2.30.2
>
Absolutely in favour of this in principle (BUG_ON() is something we should
resort to in only the direst of circumstances), one small nit - perhaps it'd be
neater to simply make this a guard clause? E.g.:-
if (!WARN_ON_ONCE(!va))
return;
...
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH 2/2] mm: vmalloc: Replace BUG_ON() by WARN_ON_ONCE()
2022-12-20 18:53 ` Lorenzo Stoakes
@ 2022-12-20 18:56 ` Lorenzo Stoakes
2022-12-21 11:39 ` Uladzislau Rezki
0 siblings, 1 reply; 8+ messages in thread
From: Lorenzo Stoakes @ 2022-12-20 18:56 UTC (permalink / raw)
To: Uladzislau Rezki (Sony)
Cc: Andrew Morton, linux-mm, LKML, Baoquan He, Christoph Hellwig,
Matthew Wilcox, Nicholas Piggin, Oleksiy Avramchenko
On Tue, Dec 20, 2022 at 06:53:18PM +0000, Lorenzo Stoakes wrote:
[snip
> Absolutely in favour of this in principle (BUG_ON() is something we should
> resort to in only the direst of circumstances), one small nit - perhaps it'd be
> neater to simply make this a guard clause? E.g.:-
>
> if (!WARN_ON_ONCE(!va))
> return;
>
> ...
Made a mistake here, meant to say
if (WARN_ON_ONCE(!va))
return;
Of course :)
Apologies, only just noticed you are sending a v2, perhaps something to consider
for it? But will hold off further review until you send it! :)
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 2/2] mm: vmalloc: Replace BUG_ON() by WARN_ON_ONCE()
2022-12-20 18:56 ` Lorenzo Stoakes
@ 2022-12-21 11:39 ` Uladzislau Rezki
0 siblings, 0 replies; 8+ messages in thread
From: Uladzislau Rezki @ 2022-12-21 11:39 UTC (permalink / raw)
To: Lorenzo Stoakes
Cc: Uladzislau Rezki (Sony), Andrew Morton, linux-mm, LKML,
Baoquan He, Christoph Hellwig, Matthew Wilcox, Nicholas Piggin,
Oleksiy Avramchenko
On Tue, Dec 20, 2022 at 06:56:38PM +0000, Lorenzo Stoakes wrote:
> On Tue, Dec 20, 2022 at 06:53:18PM +0000, Lorenzo Stoakes wrote:
> [snip
> > Absolutely in favour of this in principle (BUG_ON() is something we should
> > resort to in only the direst of circumstances), one small nit - perhaps it'd be
> > neater to simply make this a guard clause? E.g.:-
> >
> > if (!WARN_ON_ONCE(!va))
> > return;
> >
> > ...
>
> Made a mistake here, meant to say
>
> if (WARN_ON_ONCE(!va))
> return;
>
Agree. This looks better. Less confusing :)
I will post a v2.
--
Uladzislau Rezki
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 1/2] mm: vmalloc: Avoid a double lookup of freed VA in a tree
2022-12-20 18:27 [PATCH 1/2] mm: vmalloc: Avoid a double lookup of freed VA in a tree Uladzislau Rezki (Sony)
2022-12-20 18:27 ` [PATCH 2/2] mm: vmalloc: Replace BUG_ON() by WARN_ON_ONCE() Uladzislau Rezki (Sony)
@ 2022-12-20 18:45 ` Uladzislau Rezki
2022-12-20 18:46 ` Uladzislau Rezki
1 sibling, 1 reply; 8+ messages in thread
From: Uladzislau Rezki @ 2022-12-20 18:45 UTC (permalink / raw)
To: Uladzislau Rezki (Sony)
Cc: Andrew Morton, linux-mm, LKML, Baoquan He, Christoph Hellwig,
Matthew Wilcox, Nicholas Piggin, Oleksiy Avramchenko
On Tue, Dec 20, 2022 at 07:27:03PM +0100, Uladzislau Rezki (Sony) wrote:
> When a VA is freed over a main path, for example by invoking
> the vfree() function, a tree is accessed two times what is odd:
>
> vfree():
> __vunmap()
> __find_vmap_area()
> vm_remove_mappings()
> remove_vm_area()
> __find_vmap_area()
>
> __find_vmap_area() are called two times. Fix it by introducing
> a find_unlink_vmap_area() helper that finds and un-links a VA
> from a tree.
>
> Performance test results on a single CPU:
>
> - fix_size_alloc_test loops: 1000000 avg: 476847 usec
> - full_fit_alloc_test loops: 1000000 avg: 806746 usec
> - long_busy_list_alloc_test loops: 1000000 avg: 13552093 usec
> - random_size_alloc_test loops: 1000000 avg: 7441322 usec
> - fix_align_alloc_test loops: 1000000 avg: 1411132 usec
> All test took worker0=87650866284 cycles
>
> - fix_size_alloc_test loops: 1000000 avg: 490713 usec
> - full_fit_alloc_test loops: 1000000 avg: 579162 usec
> - long_busy_list_alloc_test loops: 1000000 avg: 10485448 usec
> - random_size_alloc_test loops: 1000000 avg: 5824449 usec
> - fix_align_alloc_test loops: 1000000 avg: 984735 usec
> All test took worker0=67952362802 cycles
>
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
> ---
> mm/vmalloc.c | 40 ++++++++++++++++++++++++++++------------
> 1 file changed, 28 insertions(+), 12 deletions(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 9e30f0b39203..0fc38c36e0df 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -1825,9 +1825,14 @@ static void free_vmap_area_noflush(struct vmap_area *va)
> unsigned long va_start = va->va_start;
> unsigned long nr_lazy;
>
> - spin_lock(&vmap_area_lock);
> - unlink_va(va, &vmap_area_root);
> - spin_unlock(&vmap_area_lock);
> + /*
> + * A free_vmap_block() is left. It is NOT a main free path.
> + */
> + if (!list_empty(&va->list)) {
> + spin_lock(&vmap_area_lock);
> + unlink_va(va, &vmap_area_root);
> + spin_unlock(&vmap_area_lock);
> + }
>
> nr_lazy = atomic_long_add_return((va->va_end - va->va_start) >>
> PAGE_SHIFT, &vmap_lazy_nr);
> @@ -1871,6 +1876,19 @@ struct vmap_area *find_vmap_area(unsigned long addr)
> return va;
> }
>
> +static struct vmap_area *find_unlink_vmap_area(unsigned long addr)
> +{
> + struct vmap_area *va;
> +
> + spin_lock(&vmap_area_lock);
> + va = __find_vmap_area(addr, &vmap_area_root);
> + if (va)
> + unlink_va(va, &vmap_area_root);
> + spin_unlock(&vmap_area_lock);
> +
> + return va;
> +}
> +
> /*** Per cpu kva allocator ***/
>
> /*
> @@ -2236,7 +2254,7 @@ void vm_unmap_ram(const void *mem, unsigned int count)
> return;
> }
>
> - va = find_vmap_area(addr);
> + va = find_unlink_vmap_area(addr);
> BUG_ON(!va);
> debug_check_no_locks_freed((void *)va->va_start,
> (va->va_end - va->va_start));
> @@ -2607,21 +2625,16 @@ struct vm_struct *remove_vm_area(const void *addr)
>
> might_sleep();
>
> - spin_lock(&vmap_area_lock);
> - va = __find_vmap_area((unsigned long)addr, &vmap_area_root);
> - if (va && va->vm) {
> + va = find_unlink_vmap_area((unsigned long) addr);
> + if (va) {
> struct vm_struct *vm = va->vm;
>
> - va->vm = NULL;
> - spin_unlock(&vmap_area_lock);
> -
> kasan_free_module_shadow(vm);
> free_unmap_vmap_area(va);
>
> return vm;
> }
>
> - spin_unlock(&vmap_area_lock);
> return NULL;
> }
>
> @@ -2690,6 +2703,7 @@ static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages)
> static void __vunmap(const void *addr, int deallocate_pages)
> {
> struct vm_struct *area;
> + struct vmap_area *va;
>
> if (!addr)
> return;
> @@ -2698,7 +2712,9 @@ static void __vunmap(const void *addr, int deallocate_pages)
> addr))
> return;
>
> - area = find_vm_area(addr);
> + va = find_unlink_vmap_area((unsigned long)addr);
> + area = va->vm;
> +
> if (unlikely(!area)) {
> WARN(1, KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n",
> addr);
> --
> 2.30.2
>
Will send a v2.
--
Uladzislau Rezki
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH 1/2] mm: vmalloc: Avoid a double lookup of freed VA in a tree
2022-12-20 18:45 ` [PATCH 1/2] mm: vmalloc: Avoid a double lookup of freed VA in a tree Uladzislau Rezki
@ 2022-12-20 18:46 ` Uladzislau Rezki
0 siblings, 0 replies; 8+ messages in thread
From: Uladzislau Rezki @ 2022-12-20 18:46 UTC (permalink / raw)
To: Andrew Morton
Cc: Andrew Morton, linux-mm, LKML, Baoquan He, Christoph Hellwig,
Matthew Wilcox, Nicholas Piggin, Oleksiy Avramchenko
On Tue, Dec 20, 2022 at 07:45:20PM +0100, Uladzislau Rezki wrote:
> On Tue, Dec 20, 2022 at 07:27:03PM +0100, Uladzislau Rezki (Sony) wrote:
> > When a VA is freed over a main path, for example by invoking
> > the vfree() function, a tree is accessed two times what is odd:
> >
> > vfree():
> > __vunmap()
> > __find_vmap_area()
> > vm_remove_mappings()
> > remove_vm_area()
> > __find_vmap_area()
> >
> > __find_vmap_area() are called two times. Fix it by introducing
> > a find_unlink_vmap_area() helper that finds and un-links a VA
> > from a tree.
> >
> > Performance test results on a single CPU:
> >
> > - fix_size_alloc_test loops: 1000000 avg: 476847 usec
> > - full_fit_alloc_test loops: 1000000 avg: 806746 usec
> > - long_busy_list_alloc_test loops: 1000000 avg: 13552093 usec
> > - random_size_alloc_test loops: 1000000 avg: 7441322 usec
> > - fix_align_alloc_test loops: 1000000 avg: 1411132 usec
> > All test took worker0=87650866284 cycles
> >
> > - fix_size_alloc_test loops: 1000000 avg: 490713 usec
> > - full_fit_alloc_test loops: 1000000 avg: 579162 usec
> > - long_busy_list_alloc_test loops: 1000000 avg: 10485448 usec
> > - random_size_alloc_test loops: 1000000 avg: 5824449 usec
> > - fix_align_alloc_test loops: 1000000 avg: 984735 usec
> > All test took worker0=67952362802 cycles
> >
> > Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
> > ---
> > mm/vmalloc.c | 40 ++++++++++++++++++++++++++++------------
> > 1 file changed, 28 insertions(+), 12 deletions(-)
> >
> > diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> > index 9e30f0b39203..0fc38c36e0df 100644
> > --- a/mm/vmalloc.c
> > +++ b/mm/vmalloc.c
> > @@ -1825,9 +1825,14 @@ static void free_vmap_area_noflush(struct vmap_area *va)
> > unsigned long va_start = va->va_start;
> > unsigned long nr_lazy;
> >
> > - spin_lock(&vmap_area_lock);
> > - unlink_va(va, &vmap_area_root);
> > - spin_unlock(&vmap_area_lock);
> > + /*
> > + * A free_vmap_block() is left. It is NOT a main free path.
> > + */
> > + if (!list_empty(&va->list)) {
> > + spin_lock(&vmap_area_lock);
> > + unlink_va(va, &vmap_area_root);
> > + spin_unlock(&vmap_area_lock);
> > + }
> >
> > nr_lazy = atomic_long_add_return((va->va_end - va->va_start) >>
> > PAGE_SHIFT, &vmap_lazy_nr);
> > @@ -1871,6 +1876,19 @@ struct vmap_area *find_vmap_area(unsigned long addr)
> > return va;
> > }
> >
> > +static struct vmap_area *find_unlink_vmap_area(unsigned long addr)
> > +{
> > + struct vmap_area *va;
> > +
> > + spin_lock(&vmap_area_lock);
> > + va = __find_vmap_area(addr, &vmap_area_root);
> > + if (va)
> > + unlink_va(va, &vmap_area_root);
> > + spin_unlock(&vmap_area_lock);
> > +
> > + return va;
> > +}
> > +
> > /*** Per cpu kva allocator ***/
> >
> > /*
> > @@ -2236,7 +2254,7 @@ void vm_unmap_ram(const void *mem, unsigned int count)
> > return;
> > }
> >
> > - va = find_vmap_area(addr);
> > + va = find_unlink_vmap_area(addr);
> > BUG_ON(!va);
> > debug_check_no_locks_freed((void *)va->va_start,
> > (va->va_end - va->va_start));
> > @@ -2607,21 +2625,16 @@ struct vm_struct *remove_vm_area(const void *addr)
> >
> > might_sleep();
> >
> > - spin_lock(&vmap_area_lock);
> > - va = __find_vmap_area((unsigned long)addr, &vmap_area_root);
> > - if (va && va->vm) {
> > + va = find_unlink_vmap_area((unsigned long) addr);
> > + if (va) {
> > struct vm_struct *vm = va->vm;
> >
> > - va->vm = NULL;
> > - spin_unlock(&vmap_area_lock);
> > -
> > kasan_free_module_shadow(vm);
> > free_unmap_vmap_area(va);
> >
> > return vm;
> > }
> >
> > - spin_unlock(&vmap_area_lock);
> > return NULL;
> > }
> >
> > @@ -2690,6 +2703,7 @@ static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages)
> > static void __vunmap(const void *addr, int deallocate_pages)
> > {
> > struct vm_struct *area;
> > + struct vmap_area *va;
> >
> > if (!addr)
> > return;
> > @@ -2698,7 +2712,9 @@ static void __vunmap(const void *addr, int deallocate_pages)
> > addr))
> > return;
> >
> > - area = find_vm_area(addr);
> > + va = find_unlink_vmap_area((unsigned long)addr);
> > + area = va->vm;
> > +
> > if (unlikely(!area)) {
> > WARN(1, KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n",
> > addr);
> > --
> > 2.30.2
> >
Will send a v2.
--
Uladzislau Rezki
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2022-12-21 11:39 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2022-12-20 18:27 [PATCH 1/2] mm: vmalloc: Avoid a double lookup of freed VA in a tree Uladzislau Rezki (Sony)
2022-12-20 18:27 ` [PATCH 2/2] mm: vmalloc: Replace BUG_ON() by WARN_ON_ONCE() Uladzislau Rezki (Sony)
2022-12-20 18:45 ` Uladzislau Rezki
2022-12-20 18:53 ` Lorenzo Stoakes
2022-12-20 18:56 ` Lorenzo Stoakes
2022-12-21 11:39 ` Uladzislau Rezki
2022-12-20 18:45 ` [PATCH 1/2] mm: vmalloc: Avoid a double lookup of freed VA in a tree Uladzislau Rezki
2022-12-20 18:46 ` Uladzislau Rezki
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