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 jin.xiao@intel.com
drivers/md/dm-bufio.c | 4 ++-- drivers/md/dm-verity-target.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-)
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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.
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Thanks, I will resend to review without the stable mail list.