[PATCH bpf 0/2] bpf: Shorten pack_mutex critical sections

[Puranjay Mohan <puranjay@kernel.org>]

Patch 2 moves bpf_arch_text_invalidate() out of pack_mutex, as
suggested on v1 [1].

That makes the frees fast enough to hit a deadlock that was already
there: the pack_mutex owner frees an empty pack and waits in
flush_work() for vmalloc purge work, which cannot run while
bpf_prog_free_deferred() items waiting for pack_mutex fill the
system_percpu_wq pool. Patch 1 allocates and frees pack memory without
pack_mutex. Seen on arm64; x86 and powerpc take the same path.

Changes since v1:
- Invalidate before taking pack_mutex on all archs, instead of dropping
  and retaking it on arm64
- New patch 1 for the deadlock

[1] https://lore.kernel.org/bpf/20261024031046.625578-1-alexei.starovoitov@gmail.com/

Puranjay Mohan (2):
  bpf: Don't allocate and free prog pack memory with pack_mutex held
  bpf: Invalidate freed prog pack memory without holding pack_mutex

 kernel/bpf/core.c | 58 +++++++++++++++++++++++++++++++----------------
 1 file changed, 39 insertions(+), 19 deletions(-)


base-commit: 9abe2c42ecab6c86b54838d2d645ca2e10204606
-- 
2.53.0-Meta