Merge branch 'bpf-fix-lru-nmi-tracepoint-re-entry-deadlock'

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Mykyta Yatsenko says:

====================
bpf: Fix LRU NMI/tracepoint re-entry deadlock

This series fixes AA-deadlocks where NMI and tracepoint BPF programs
re-enter the per-CPU or global LRU lock already held on the same CPU
(syzbot c69a0a2c816716f1e0d5, 18b26edb69b2e19f3b33).

Patch 1 converts every LRU lock site to rqspinlock_t
and adds explicit recovery for some failures so no node leaks.

Patch 2 refreshes Documentation/bpf/map_lru_hash_update.dot to show
the new rqspinlock failure exits and recovery routes.

Patch 3 introduces a stress test.

Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
---
Changes in v3:
- Removed RFC tag
- Link to v2: https://patch.msgid.link/20260603-lru_map_spin-v2-0-7060cfb6cdac@meta.com

Changes in v2:
- Patch 1: __bpf_lru_node_move_in() now clears pending_free only when
  moving to the FREE list.
- Patch 3: address sashiko's feedback.
- Link to v1: https://patch.msgid.link/20260528-lru_map_spin-v1-0-4f52223170cf@meta.com
====================

Link: https://patch.msgid.link/20260607-lru_map_spin-v3-0-bcd9332e911b@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

...

This commit is contained in:

Alexei Starovoitov 2026-06-07 18:46:13 -07:00

parent 1444ee886e 6e1e4a9d60

commit 63a6f3bc62

5 changed files with 437 additions and 73 deletions

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44

Documentation/bpf/map_lru_hash_update.dot

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165

kernel/bpf/bpf_lru_list.c

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25

kernel/bpf/bpf_lru_list.h

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243

tools/testing/selftests/bpf/prog_tests/lru_lock_nmi.c

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33

tools/testing/selftests/bpf/progs/lru_lock_nmi.c

View file