We hit the BUG() report at include/linux/scatterlist.h:144!
The callback is as bellow:
=> verity_work
=> verity_hash_for_block
=> verity_verify_level
=> verity_hash
=> verity_hash_update
=> sg_init_one
=> sg_set_buf
More debug shows the root cause. When creating dufio client it
uses the __vmalloc() to allocate the buffer data for the reserved
dm_buffer. The buffer that allocated by the __vmalloc() is invalid
according to the __virt_addr_valid().
Mostly the reserved dm_buffer is not touched. But occasionally
it might fail to allocate the dm_buffer data when we try to
allocate in the __alloc_buffer_wait_no_callback(). Then it has
to take the reserved dm_buffer for usage. Finally it reports the
BUG() as virt_addr_valid() detects the buffer data address is invalid.
The patch is to adjust the reserved buffer for dm-verity-target. We
allocated two dm_buffers into the reserved buffers list when creating
the buffer interface. The first dm_buffer in the reserved buffer list
is allocated by the __vmalloc(), it's not used after that. The second
dm_buffer in the reserved buffer list is allocated by the
__get_free_pages() which can be consumed after that.
Signed-off-by: xiao jin <[email protected]>
---
drivers/md/dm-bufio.c | 4 ++--
drivers/md/dm-verity-target.c | 2 +-
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index dc385b7..3b7ca5e 100644
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -841,7 +841,7 @@ static struct dm_buffer *__alloc_buffer_wait_no_callback(struct dm_bufio_client
tried_noio_alloc = true;
}
- if (!list_empty(&c->reserved_buffers)) {
+ if (!c->need_reserved_buffers) {
b = list_entry(c->reserved_buffers.next,
struct dm_buffer, lru_list);
list_del(&b->lru_list);
@@ -1701,7 +1701,7 @@ struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsign
goto bad;
}
- while (c->need_reserved_buffers) {
+ if (list_empty(&c->reserved_buffers)) {
struct dm_buffer *b = alloc_buffer(c, GFP_KERNEL);
if (!b) {
diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
index 12decdbd7..40c66fc 100644
--- a/drivers/md/dm-verity-target.c
+++ b/drivers/md/dm-verity-target.c
@@ -1107,7 +1107,7 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
v->hash_blocks = hash_position;
v->bufio = dm_bufio_client_create(v->hash_dev->bdev,
- 1 << v->hash_dev_block_bits, 1, sizeof(struct buffer_aux),
+ 1 << v->hash_dev_block_bits, 2, sizeof(struct buffer_aux),
dm_bufio_alloc_callback, NULL);
if (IS_ERR(v->bufio)) {
ti->error = "Cannot initialize dm-bufio";
--
2.7.4
On Wed, Aug 08, 2018 at 01:07:03PM +0800, xiao jin wrote:
> We hit the BUG() report at include/linux/scatterlist.h:144!
> The callback is as bellow:
> => verity_work
> => verity_hash_for_block
> => verity_verify_level
> => verity_hash
> => verity_hash_update
> => sg_init_one
> => sg_set_buf
>
> More debug shows the root cause. When creating dufio client it
> uses the __vmalloc() to allocate the buffer data for the reserved
> dm_buffer. The buffer that allocated by the __vmalloc() is invalid
> according to the __virt_addr_valid().
>
> Mostly the reserved dm_buffer is not touched. But occasionally
> it might fail to allocate the dm_buffer data when we try to
> allocate in the __alloc_buffer_wait_no_callback(). Then it has
> to take the reserved dm_buffer for usage. Finally it reports the
> BUG() as virt_addr_valid() detects the buffer data address is invalid.
>
> The patch is to adjust the reserved buffer for dm-verity-target. We
> allocated two dm_buffers into the reserved buffers list when creating
> the buffer interface. The first dm_buffer in the reserved buffer list
> is allocated by the __vmalloc(), it's not used after that. The second
> dm_buffer in the reserved buffer list is allocated by the
> __get_free_pages() which can be consumed after that.
>
> Signed-off-by: xiao jin <[email protected]>
> ---
> drivers/md/dm-bufio.c | 4 ++--
> drivers/md/dm-verity-target.c | 2 +-
> 2 files changed, 3 insertions(+), 3 deletions(-)
>
<formletter>
This is not the correct way to submit patches for inclusion in the
stable kernel tree. Please read:
https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.
</formletter>
On 2018年08月08日 13:25, Greg KH wrote:
> On Wed, Aug 08, 2018 at 01:07:03PM +0800, xiao jin wrote:
>> We hit the BUG() report at include/linux/scatterlist.h:144!
>> The callback is as bellow:
>> => verity_work
>> => verity_hash_for_block
>> => verity_verify_level
>> => verity_hash
>> => verity_hash_update
>> => sg_init_one
>> => sg_set_buf
>>
>> More debug shows the root cause. When creating dufio client it
>> uses the __vmalloc() to allocate the buffer data for the reserved
>> dm_buffer. The buffer that allocated by the __vmalloc() is invalid
>> according to the __virt_addr_valid().
>>
>> Mostly the reserved dm_buffer is not touched. But occasionally
>> it might fail to allocate the dm_buffer data when we try to
>> allocate in the __alloc_buffer_wait_no_callback(). Then it has
>> to take the reserved dm_buffer for usage. Finally it reports the
>> BUG() as virt_addr_valid() detects the buffer data address is invalid.
>>
>> The patch is to adjust the reserved buffer for dm-verity-target. We
>> allocated two dm_buffers into the reserved buffers list when creating
>> the buffer interface. The first dm_buffer in the reserved buffer list
>> is allocated by the __vmalloc(), it's not used after that. The second
>> dm_buffer in the reserved buffer list is allocated by the
>> __get_free_pages() which can be consumed after that.
>>
>> Signed-off-by: xiao jin <[email protected]>
>> ---
>> drivers/md/dm-bufio.c | 4 ++--
>> drivers/md/dm-verity-target.c | 2 +-
>> 2 files changed, 3 insertions(+), 3 deletions(-)
>>
> <formletter>
>
> This is not the correct way to submit patches for inclusion in the
> stable kernel tree. Please read:
> https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
> for how to do this properly.
>
> </formletter>
Thanks, I will resend to review without the stable mail list.