Hi, Christoph!
在 2022/07/07 15:20, Yu Kuai 写道:
在 2022/07/07 13:24, Christoph Hellwig 写道:
On Thu, Jul 07, 2022 at 11:29:26AM +0800, Yu Kuai wrote:
We found that this patch fix a nullptr crash in our test:
Do you think it's ok to backport this patch(and all realted patches) to
lts, or it's better to fix that bio can be submitted with queue
uninitialized from block layer?
Given how long ago this was I do not remember offhand how much prep
work this would require. The patch itself is of course tiny and
backportable, but someone will need to do the work and figure out how
much else would have to be backported.
Ok, I'll try to figure out that, and backport them.(At least to 5.10.y)
While reviewing the code, I didn't found any protection that
bd_link_disk_holder() won't concurrent with
bd_register_pending_holders(). If they do can concurrent,
following scenario is problematic:
t1 t2
device_add_disk
disk->slave_dir = kobject_create_and_add
bd_link_disk_holder
__link_disk_holder
list_add
bd_register_pending_holders
list_for_each_entry
__link_disk_holder -> -EEXIST
In this case, I think maybe ignore '-EEXIST' is fine.
I'm not familiar with dm, and I'm not sure if I missed something,
please kindly correct me if I'm wrong.
Thanks,
Kuai
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