On 11/16/2022 1:27 PM, Alexei Starovoitov wrote:
On Mon, Nov 14, 2022 at 5:31 AM Xu Kuohai <xukuohai@xxxxxxxxxx> wrote:
bpf_selem_alloc function is used by inode_storage, sk_storage and
task_storage maps to set map value, for these map types, there may
be a spin lock in the map value, so if we use memcpy to copy the whole
map value from user, the spin lock field may be initialized incorrectly.
Since the spin lock field is zeroed by kzalloc, call copy_map_value
instead of memcpy to skip copying the spin lock field to fix it.
Fixes: 6ac99e8f23d4 ("bpf: Introduce bpf sk local storage")
The tag is wrong. When local storage was introduced it was not
possible to use spin_locks there.
Pls resubmit.
.
No, spin_lock was introduced by d83525ca62cf ("bpf: introduce bpf_spin_lock"),
before 6ac99e8f23d4 ("bpf: Introduce bpf sk local storage").
To confirm this, I built a kernel image on comit 6ac99e8f23d4 ("bpf: Introduce bpf sk local storage")
and run test case posted in patch 2, a softlockup was triggered. Then I picked
this patch and tried again, nothing failed.
