* Re: [PATCH] gpu: ttm: fix GPF in ttm_bo_release
@ 2021-07-08 10:56 ` Christian König
0 siblings, 0 replies; 14+ messages in thread
From: Christian König @ 2021-07-08 10:56 UTC (permalink / raw)
To: Pavel Skripkin, ray.huang, airlied; +Cc: linux-kernel, dri-devel
Am 08.07.21 um 12:09 schrieb Pavel Skripkin:
> On Thu, 8 Jul 2021 11:37:01 +0300
> Pavel Skripkin <paskripkin@gmail.com> wrote:
>
>> On Thu, 8 Jul 2021 08:49:48 +0200
>> Christian König <christian.koenig@amd.com> wrote:
>>
>>> Am 07.07.21 um 20:51 schrieb Pavel Skripkin:
>>>> My local syzbot instance hit GPF in ttm_bo_release().
>>>> Unfortunately, syzbot didn't produce a reproducer for this, but I
>>>> found out possible scenario:
>>>>
>>>> drm_gem_vram_create() <-- drm_gem_vram_object kzalloced
>>>> (bo embedded in this object)
>>>> ttm_bo_init()
>>>> ttm_bo_init_reserved()
>>>> ttm_resource_alloc()
>>>> man->func->alloc() <-- allocation failure
>>>> ttm_bo_put()
>>>> ttm_bo_release()
>>>> ttm_mem_io_free() <-- bo->resource == NULL passed
>>>> as second argument
>>>> *GPF*
>>>>
>>>> So, I've added check in ttm_bo_release() to avoid passing
>>>> NULL as second argument to ttm_mem_io_free().
>> Hi, Christian!
>>
>> Thank you for quick feedback :)
>>
>>> There is another ocassion of this a bit down before we call
>>> ttm_bo_move_to_lru_tail() apart from that good catch.
>>>
>> Did you mean, that ttm_bo_move_to_lru_tail() should have NULL check
>> too?
Yes, exactly that.
>> I checked it's realization, and, I think, NULL check is necessary
>> there, since mem pointer is dereferenced w/o any checking
>>
>>> But I'm wondering if we should make the functions NULL save instead
>>> of the external check.
>>>
>> I tried to find more possible scenarios of GPF in ttm_bo_release(),
>> but I didn't find one. But, yes, moving NULL check inside
>> ttm_mem_io_free() is more general approach and it will defend this
>> function from GPFs in the future.
>>
>>
>>
>> With regards,
>> Pavel Skripkin
>>
> I misclicked and sent this email to Christian privately :(
>
> Added all thread participants back, sorry.
No problem.
Do you want to update your patch or should I take care of this?
Thanks,
Christian.
>
>
>
> With regards,
> Pavel Skripkin
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] gpu: ttm: fix GPF in ttm_bo_release
2021-07-08 10:56 ` Christian König
@ 2021-07-08 11:04 ` Pavel Skripkin
-1 siblings, 0 replies; 14+ messages in thread
From: Pavel Skripkin @ 2021-07-08 11:04 UTC (permalink / raw)
To: Christian König; +Cc: ray.huang, airlied, dri-devel, linux-kernel
On Thu, 8 Jul 2021 12:56:19 +0200
Christian König <christian.koenig@amd.com> wrote:
> Am 08.07.21 um 12:09 schrieb Pavel Skripkin:
> > On Thu, 8 Jul 2021 11:37:01 +0300
> > Pavel Skripkin <paskripkin@gmail.com> wrote:
> >
> >> On Thu, 8 Jul 2021 08:49:48 +0200
> >> Christian König <christian.koenig@amd.com> wrote:
> >>
> >>> Am 07.07.21 um 20:51 schrieb Pavel Skripkin:
> >>>> My local syzbot instance hit GPF in ttm_bo_release().
> >>>> Unfortunately, syzbot didn't produce a reproducer for this, but I
> >>>> found out possible scenario:
> >>>>
> >>>> drm_gem_vram_create() <-- drm_gem_vram_object
> >>>> kzalloced (bo embedded in this object)
> >>>> ttm_bo_init()
> >>>> ttm_bo_init_reserved()
> >>>> ttm_resource_alloc()
> >>>> man->func->alloc() <-- allocation failure
> >>>> ttm_bo_put()
> >>>> ttm_bo_release()
> >>>> ttm_mem_io_free() <-- bo->resource == NULL passed
> >>>> as second argument
> >>>> *GPF*
> >>>>
> >>>> So, I've added check in ttm_bo_release() to avoid passing
> >>>> NULL as second argument to ttm_mem_io_free().
> >> Hi, Christian!
> >>
> >> Thank you for quick feedback :)
> >>
> >>> There is another ocassion of this a bit down before we call
> >>> ttm_bo_move_to_lru_tail() apart from that good catch.
> >>>
> >> Did you mean, that ttm_bo_move_to_lru_tail() should have NULL check
> >> too?
>
> Yes, exactly that.
>
> >> I checked it's realization, and, I think, NULL check is necessary
> >> there, since mem pointer is dereferenced w/o any checking
> >>
> >>> But I'm wondering if we should make the functions NULL save
> >>> instead of the external check.
> >>>
> >> I tried to find more possible scenarios of GPF in ttm_bo_release(),
> >> but I didn't find one. But, yes, moving NULL check inside
> >> ttm_mem_io_free() is more general approach and it will defend this
> >> function from GPFs in the future.
> >>
> >>
> >>
> >> With regards,
> >> Pavel Skripkin
> >>
> > I misclicked and sent this email to Christian privately :(
> >
> > Added all thread participants back, sorry.
>
> No problem.
>
> Do you want to update your patch or should I take care of this?
>
Yes, I will send v2 soon. Thank you!
With regards,
Pavel Skripkin
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] gpu: ttm: fix GPF in ttm_bo_release
@ 2021-07-08 11:04 ` Pavel Skripkin
0 siblings, 0 replies; 14+ messages in thread
From: Pavel Skripkin @ 2021-07-08 11:04 UTC (permalink / raw)
To: Christian König; +Cc: airlied, ray.huang, linux-kernel, dri-devel
On Thu, 8 Jul 2021 12:56:19 +0200
Christian König <christian.koenig@amd.com> wrote:
> Am 08.07.21 um 12:09 schrieb Pavel Skripkin:
> > On Thu, 8 Jul 2021 11:37:01 +0300
> > Pavel Skripkin <paskripkin@gmail.com> wrote:
> >
> >> On Thu, 8 Jul 2021 08:49:48 +0200
> >> Christian König <christian.koenig@amd.com> wrote:
> >>
> >>> Am 07.07.21 um 20:51 schrieb Pavel Skripkin:
> >>>> My local syzbot instance hit GPF in ttm_bo_release().
> >>>> Unfortunately, syzbot didn't produce a reproducer for this, but I
> >>>> found out possible scenario:
> >>>>
> >>>> drm_gem_vram_create() <-- drm_gem_vram_object
> >>>> kzalloced (bo embedded in this object)
> >>>> ttm_bo_init()
> >>>> ttm_bo_init_reserved()
> >>>> ttm_resource_alloc()
> >>>> man->func->alloc() <-- allocation failure
> >>>> ttm_bo_put()
> >>>> ttm_bo_release()
> >>>> ttm_mem_io_free() <-- bo->resource == NULL passed
> >>>> as second argument
> >>>> *GPF*
> >>>>
> >>>> So, I've added check in ttm_bo_release() to avoid passing
> >>>> NULL as second argument to ttm_mem_io_free().
> >> Hi, Christian!
> >>
> >> Thank you for quick feedback :)
> >>
> >>> There is another ocassion of this a bit down before we call
> >>> ttm_bo_move_to_lru_tail() apart from that good catch.
> >>>
> >> Did you mean, that ttm_bo_move_to_lru_tail() should have NULL check
> >> too?
>
> Yes, exactly that.
>
> >> I checked it's realization, and, I think, NULL check is necessary
> >> there, since mem pointer is dereferenced w/o any checking
> >>
> >>> But I'm wondering if we should make the functions NULL save
> >>> instead of the external check.
> >>>
> >> I tried to find more possible scenarios of GPF in ttm_bo_release(),
> >> but I didn't find one. But, yes, moving NULL check inside
> >> ttm_mem_io_free() is more general approach and it will defend this
> >> function from GPFs in the future.
> >>
> >>
> >>
> >> With regards,
> >> Pavel Skripkin
> >>
> > I misclicked and sent this email to Christian privately :(
> >
> > Added all thread participants back, sorry.
>
> No problem.
>
> Do you want to update your patch or should I take care of this?
>
Yes, I will send v2 soon. Thank you!
With regards,
Pavel Skripkin
^ permalink raw reply [flat|nested] 14+ messages in thread
* [PATCH v2] gpu: ttm: add missing NULL checks
2021-07-08 10:56 ` Christian König
@ 2021-07-08 11:25 ` Pavel Skripkin
-1 siblings, 0 replies; 14+ messages in thread
From: Pavel Skripkin @ 2021-07-08 11:25 UTC (permalink / raw)
To: christian.koenig, ray.huang, airlied
Cc: dri-devel, linux-kernel, Pavel Skripkin
My local syzbot instance hit GPF in ttm_bo_release().
Unfortunately, syzbot didn't produce a reproducer for this, but I
found out possible scenario:
drm_gem_vram_create() <-- drm_gem_vram_object kzalloced
(bo embedded in this object)
ttm_bo_init()
ttm_bo_init_reserved()
ttm_resource_alloc()
man->func->alloc() <-- allocation failure
ttm_bo_put()
ttm_bo_release()
ttm_mem_io_free() <-- bo->resource == NULL passed
as second argument
*GPF*
Added NULL check inside ttm_mem_io_free() to prevent reported GPF and
make this function NULL save in future.
Same problem was in ttm_bo_move_to_lru_tail() as Christian reported.
ttm_bo_move_to_lru_tail() is called in ttm_bo_release() and mem pointer
can be NULL as well as in ttm_mem_io_free().
Fail log:
KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]
CPU: 1 PID: 10419 Comm: syz-executor.3 Not tainted 5.13.0-rc7-next-20210625 #7
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a-rebuilt.opensuse.org 04/01/2014
RIP: 0010:ttm_mem_io_free+0x28/0x170 drivers/gpu/drm/ttm/ttm_bo_util.c:66
Code: b1 90 41 56 41 55 41 54 55 48 89 fd 53 48 89 f3 e8 cd 19 24 fd 4c 8d 6b 20 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 2a 01 00 00 4c 8b 63 20 31 ff 4c 89 e6 e8 00 1f
RSP: 0018:ffffc900141df968 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc90010da0000
RDX: 0000000000000004 RSI: ffffffff84513ea3 RDI: ffff888041fbc010
RBP: ffff888041fbc010 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000020 R14: ffff88806b258800 R15: ffff88806b258a38
FS: 00007fa6e9845640(0000) GS:ffff88807ec00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fad61265e18 CR3: 000000005ad79000 CR4: 0000000000350ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
ttm_bo_release+0xd94/0x10a0 drivers/gpu/drm/ttm/ttm_bo.c:422
kref_put include/linux/kref.h:65 [inline]
ttm_bo_put drivers/gpu/drm/ttm/ttm_bo.c:470 [inline]
ttm_bo_init_reserved+0x7cb/0x960 drivers/gpu/drm/ttm/ttm_bo.c:1050
ttm_bo_init+0x105/0x270 drivers/gpu/drm/ttm/ttm_bo.c:1074
drm_gem_vram_create+0x332/0x4c0 drivers/gpu/drm/drm_gem_vram_helper.c:228
Fixes: d3116756a710 ("drm/ttm: rename bo->mem and make it a pointer")
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
---
Changes in v2:
1. Added NULL check in ttm_bo_move_to_lru_tail()
2. Changed subject line, since NULL check added in 2 funtions
---
drivers/gpu/drm/ttm/ttm_bo.c | 3 +++
drivers/gpu/drm/ttm/ttm_bo_util.c | 3 +++
2 files changed, 6 insertions(+)
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 1b950b45cf4b..8d7fd65ccced 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -102,6 +102,9 @@ void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo,
return;
}
+ if (!mem)
+ return;
+
man = ttm_manager_type(bdev, mem->mem_type);
list_move_tail(&bo->lru, &man->lru[bo->priority]);
diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
index 2f57f824e6db..763fa6f4e07d 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -63,6 +63,9 @@ int ttm_mem_io_reserve(struct ttm_device *bdev,
void ttm_mem_io_free(struct ttm_device *bdev,
struct ttm_resource *mem)
{
+ if (!mem)
+ return;
+
if (!mem->bus.offset && !mem->bus.addr)
return;
--
2.32.0
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH v2] gpu: ttm: add missing NULL checks
@ 2021-07-08 11:25 ` Pavel Skripkin
0 siblings, 0 replies; 14+ messages in thread
From: Pavel Skripkin @ 2021-07-08 11:25 UTC (permalink / raw)
To: christian.koenig, ray.huang, airlied
Cc: Pavel Skripkin, linux-kernel, dri-devel
My local syzbot instance hit GPF in ttm_bo_release().
Unfortunately, syzbot didn't produce a reproducer for this, but I
found out possible scenario:
drm_gem_vram_create() <-- drm_gem_vram_object kzalloced
(bo embedded in this object)
ttm_bo_init()
ttm_bo_init_reserved()
ttm_resource_alloc()
man->func->alloc() <-- allocation failure
ttm_bo_put()
ttm_bo_release()
ttm_mem_io_free() <-- bo->resource == NULL passed
as second argument
*GPF*
Added NULL check inside ttm_mem_io_free() to prevent reported GPF and
make this function NULL save in future.
Same problem was in ttm_bo_move_to_lru_tail() as Christian reported.
ttm_bo_move_to_lru_tail() is called in ttm_bo_release() and mem pointer
can be NULL as well as in ttm_mem_io_free().
Fail log:
KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]
CPU: 1 PID: 10419 Comm: syz-executor.3 Not tainted 5.13.0-rc7-next-20210625 #7
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a-rebuilt.opensuse.org 04/01/2014
RIP: 0010:ttm_mem_io_free+0x28/0x170 drivers/gpu/drm/ttm/ttm_bo_util.c:66
Code: b1 90 41 56 41 55 41 54 55 48 89 fd 53 48 89 f3 e8 cd 19 24 fd 4c 8d 6b 20 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 2a 01 00 00 4c 8b 63 20 31 ff 4c 89 e6 e8 00 1f
RSP: 0018:ffffc900141df968 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc90010da0000
RDX: 0000000000000004 RSI: ffffffff84513ea3 RDI: ffff888041fbc010
RBP: ffff888041fbc010 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000020 R14: ffff88806b258800 R15: ffff88806b258a38
FS: 00007fa6e9845640(0000) GS:ffff88807ec00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fad61265e18 CR3: 000000005ad79000 CR4: 0000000000350ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
ttm_bo_release+0xd94/0x10a0 drivers/gpu/drm/ttm/ttm_bo.c:422
kref_put include/linux/kref.h:65 [inline]
ttm_bo_put drivers/gpu/drm/ttm/ttm_bo.c:470 [inline]
ttm_bo_init_reserved+0x7cb/0x960 drivers/gpu/drm/ttm/ttm_bo.c:1050
ttm_bo_init+0x105/0x270 drivers/gpu/drm/ttm/ttm_bo.c:1074
drm_gem_vram_create+0x332/0x4c0 drivers/gpu/drm/drm_gem_vram_helper.c:228
Fixes: d3116756a710 ("drm/ttm: rename bo->mem and make it a pointer")
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
---
Changes in v2:
1. Added NULL check in ttm_bo_move_to_lru_tail()
2. Changed subject line, since NULL check added in 2 funtions
---
drivers/gpu/drm/ttm/ttm_bo.c | 3 +++
drivers/gpu/drm/ttm/ttm_bo_util.c | 3 +++
2 files changed, 6 insertions(+)
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 1b950b45cf4b..8d7fd65ccced 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -102,6 +102,9 @@ void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo,
return;
}
+ if (!mem)
+ return;
+
man = ttm_manager_type(bdev, mem->mem_type);
list_move_tail(&bo->lru, &man->lru[bo->priority]);
diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
index 2f57f824e6db..763fa6f4e07d 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -63,6 +63,9 @@ int ttm_mem_io_reserve(struct ttm_device *bdev,
void ttm_mem_io_free(struct ttm_device *bdev,
struct ttm_resource *mem)
{
+ if (!mem)
+ return;
+
if (!mem->bus.offset && !mem->bus.addr)
return;
--
2.32.0
^ permalink raw reply related [flat|nested] 14+ messages in thread* Re: [PATCH v2] gpu: ttm: add missing NULL checks
2021-07-08 11:25 ` Pavel Skripkin
@ 2021-07-08 11:29 ` Christian König
-1 siblings, 0 replies; 14+ messages in thread
From: Christian König @ 2021-07-08 11:29 UTC (permalink / raw)
To: Pavel Skripkin, ray.huang, airlied; +Cc: dri-devel, linux-kernel
Am 08.07.21 um 13:25 schrieb Pavel Skripkin:
> My local syzbot instance hit GPF in ttm_bo_release().
> Unfortunately, syzbot didn't produce a reproducer for this, but I
> found out possible scenario:
>
> drm_gem_vram_create() <-- drm_gem_vram_object kzalloced
> (bo embedded in this object)
> ttm_bo_init()
> ttm_bo_init_reserved()
> ttm_resource_alloc()
> man->func->alloc() <-- allocation failure
> ttm_bo_put()
> ttm_bo_release()
> ttm_mem_io_free() <-- bo->resource == NULL passed
> as second argument
> *GPF*
>
> Added NULL check inside ttm_mem_io_free() to prevent reported GPF and
> make this function NULL save in future.
>
> Same problem was in ttm_bo_move_to_lru_tail() as Christian reported.
> ttm_bo_move_to_lru_tail() is called in ttm_bo_release() and mem pointer
> can be NULL as well as in ttm_mem_io_free().
>
> Fail log:
>
> KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]
> CPU: 1 PID: 10419 Comm: syz-executor.3 Not tainted 5.13.0-rc7-next-20210625 #7
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a-rebuilt.opensuse.org 04/01/2014
> RIP: 0010:ttm_mem_io_free+0x28/0x170 drivers/gpu/drm/ttm/ttm_bo_util.c:66
> Code: b1 90 41 56 41 55 41 54 55 48 89 fd 53 48 89 f3 e8 cd 19 24 fd 4c 8d 6b 20 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 2a 01 00 00 4c 8b 63 20 31 ff 4c 89 e6 e8 00 1f
> RSP: 0018:ffffc900141df968 EFLAGS: 00010202
> RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc90010da0000
> RDX: 0000000000000004 RSI: ffffffff84513ea3 RDI: ffff888041fbc010
> RBP: ffff888041fbc010 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
> R13: 0000000000000020 R14: ffff88806b258800 R15: ffff88806b258a38
> FS: 00007fa6e9845640(0000) GS:ffff88807ec00000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007fad61265e18 CR3: 000000005ad79000 CR4: 0000000000350ee0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
> ttm_bo_release+0xd94/0x10a0 drivers/gpu/drm/ttm/ttm_bo.c:422
> kref_put include/linux/kref.h:65 [inline]
> ttm_bo_put drivers/gpu/drm/ttm/ttm_bo.c:470 [inline]
> ttm_bo_init_reserved+0x7cb/0x960 drivers/gpu/drm/ttm/ttm_bo.c:1050
> ttm_bo_init+0x105/0x270 drivers/gpu/drm/ttm/ttm_bo.c:1074
> drm_gem_vram_create+0x332/0x4c0 drivers/gpu/drm/drm_gem_vram_helper.c:228
>
> Fixes: d3116756a710 ("drm/ttm: rename bo->mem and make it a pointer")
> Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Going to push this to drm-misc-next-fixes.
Thanks,
Christian.
> ---
>
> Changes in v2:
> 1. Added NULL check in ttm_bo_move_to_lru_tail()
>
> 2. Changed subject line, since NULL check added in 2 funtions
>
> ---
> drivers/gpu/drm/ttm/ttm_bo.c | 3 +++
> drivers/gpu/drm/ttm/ttm_bo_util.c | 3 +++
> 2 files changed, 6 insertions(+)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> index 1b950b45cf4b..8d7fd65ccced 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -102,6 +102,9 @@ void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo,
> return;
> }
>
> + if (!mem)
> + return;
> +
> man = ttm_manager_type(bdev, mem->mem_type);
> list_move_tail(&bo->lru, &man->lru[bo->priority]);
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
> index 2f57f824e6db..763fa6f4e07d 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo_util.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
> @@ -63,6 +63,9 @@ int ttm_mem_io_reserve(struct ttm_device *bdev,
> void ttm_mem_io_free(struct ttm_device *bdev,
> struct ttm_resource *mem)
> {
> + if (!mem)
> + return;
> +
> if (!mem->bus.offset && !mem->bus.addr)
> return;
>
^ permalink raw reply [flat|nested] 14+ messages in thread* Re: [PATCH v2] gpu: ttm: add missing NULL checks
@ 2021-07-08 11:29 ` Christian König
0 siblings, 0 replies; 14+ messages in thread
From: Christian König @ 2021-07-08 11:29 UTC (permalink / raw)
To: Pavel Skripkin, ray.huang, airlied; +Cc: linux-kernel, dri-devel
Am 08.07.21 um 13:25 schrieb Pavel Skripkin:
> My local syzbot instance hit GPF in ttm_bo_release().
> Unfortunately, syzbot didn't produce a reproducer for this, but I
> found out possible scenario:
>
> drm_gem_vram_create() <-- drm_gem_vram_object kzalloced
> (bo embedded in this object)
> ttm_bo_init()
> ttm_bo_init_reserved()
> ttm_resource_alloc()
> man->func->alloc() <-- allocation failure
> ttm_bo_put()
> ttm_bo_release()
> ttm_mem_io_free() <-- bo->resource == NULL passed
> as second argument
> *GPF*
>
> Added NULL check inside ttm_mem_io_free() to prevent reported GPF and
> make this function NULL save in future.
>
> Same problem was in ttm_bo_move_to_lru_tail() as Christian reported.
> ttm_bo_move_to_lru_tail() is called in ttm_bo_release() and mem pointer
> can be NULL as well as in ttm_mem_io_free().
>
> Fail log:
>
> KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]
> CPU: 1 PID: 10419 Comm: syz-executor.3 Not tainted 5.13.0-rc7-next-20210625 #7
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a-rebuilt.opensuse.org 04/01/2014
> RIP: 0010:ttm_mem_io_free+0x28/0x170 drivers/gpu/drm/ttm/ttm_bo_util.c:66
> Code: b1 90 41 56 41 55 41 54 55 48 89 fd 53 48 89 f3 e8 cd 19 24 fd 4c 8d 6b 20 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 2a 01 00 00 4c 8b 63 20 31 ff 4c 89 e6 e8 00 1f
> RSP: 0018:ffffc900141df968 EFLAGS: 00010202
> RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc90010da0000
> RDX: 0000000000000004 RSI: ffffffff84513ea3 RDI: ffff888041fbc010
> RBP: ffff888041fbc010 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
> R13: 0000000000000020 R14: ffff88806b258800 R15: ffff88806b258a38
> FS: 00007fa6e9845640(0000) GS:ffff88807ec00000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007fad61265e18 CR3: 000000005ad79000 CR4: 0000000000350ee0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
> ttm_bo_release+0xd94/0x10a0 drivers/gpu/drm/ttm/ttm_bo.c:422
> kref_put include/linux/kref.h:65 [inline]
> ttm_bo_put drivers/gpu/drm/ttm/ttm_bo.c:470 [inline]
> ttm_bo_init_reserved+0x7cb/0x960 drivers/gpu/drm/ttm/ttm_bo.c:1050
> ttm_bo_init+0x105/0x270 drivers/gpu/drm/ttm/ttm_bo.c:1074
> drm_gem_vram_create+0x332/0x4c0 drivers/gpu/drm/drm_gem_vram_helper.c:228
>
> Fixes: d3116756a710 ("drm/ttm: rename bo->mem and make it a pointer")
> Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Going to push this to drm-misc-next-fixes.
Thanks,
Christian.
> ---
>
> Changes in v2:
> 1. Added NULL check in ttm_bo_move_to_lru_tail()
>
> 2. Changed subject line, since NULL check added in 2 funtions
>
> ---
> drivers/gpu/drm/ttm/ttm_bo.c | 3 +++
> drivers/gpu/drm/ttm/ttm_bo_util.c | 3 +++
> 2 files changed, 6 insertions(+)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> index 1b950b45cf4b..8d7fd65ccced 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -102,6 +102,9 @@ void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo,
> return;
> }
>
> + if (!mem)
> + return;
> +
> man = ttm_manager_type(bdev, mem->mem_type);
> list_move_tail(&bo->lru, &man->lru[bo->priority]);
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
> index 2f57f824e6db..763fa6f4e07d 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo_util.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
> @@ -63,6 +63,9 @@ int ttm_mem_io_reserve(struct ttm_device *bdev,
> void ttm_mem_io_free(struct ttm_device *bdev,
> struct ttm_resource *mem)
> {
> + if (!mem)
> + return;
> +
> if (!mem->bus.offset && !mem->bus.addr)
> return;
>
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