Merge branch 'bpf-fix-softlock-condition-in-bpf-hashmap-interation'

Merge branch 'bpf-fix-softlock-condition-in-bpf-hashmap-interation'

Brandon Kammerdiener says:

====================
This patchset fixes an endless loop condition that can occur in
bpf_for_each_hash_elem, causing the core to softlock. My understanding is
that a combination of RCU list deletion and insertion introduces the new
element after the iteration cursor and that there is a chance that an RCU
reader may in fact use this new element in iteration. The patch uses a
_safe variant of the macro which gets the next element to iterate before
executing the loop body for the current element.

I have also added a subtest in the for_each selftest that can trigger this
condition without the fix.

Changes since v2:
- Renaming and additional checks in selftests/bpf/prog_tests/for_each.c

Changes since v1:
- Added missing Signed-off-by lines to both patches
====================

Acked-by: Hou Tao <houtao1@huawei.com>
Link: https://patch.msgid.link/20250424153246.141677-1-brandon.kammerdiener@intel.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>