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| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2024-06-20 16:22:03 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2024-06-25 02:41:23 +0300 |
| commit | 78f520b7bbe579438dfc202226b3dac5607d8c7f (patch) | |
| tree | 5153f67a77881d0cb30315535265f04093828146 /net/core | |
| parent | d1542d4ae4dfdc47c9b3205ebe849ed23af213dd (diff) | |
| download | linux-78f520b7bbe579438dfc202226b3dac5607d8c7f.tar.xz | |
net: Use nested-BH locking for bpf_scratchpad.
bpf_scratchpad is a per-CPU variable and relies on disabled BH for its
locking. Without per-CPU locking in local_bh_disable() on PREEMPT_RT
this data structure requires explicit locking.
Add a local_lock_t to the data structure and use local_lock_nested_bh()
for locking. This change adds only lockdep coverage and does not alter
the functional behaviour for !PREEMPT_RT.
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Hao Luo <haoluo@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Song Liu <song@kernel.org>
Cc: Stanislav Fomichev <sdf@google.com>
Cc: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20240620132727.660738-14-bigeasy@linutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/filter.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/net/core/filter.c b/net/core/filter.c index c4f5db324f04..adb887195c3a 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -1658,9 +1658,12 @@ struct bpf_scratchpad { __be32 diff[MAX_BPF_STACK / sizeof(__be32)]; u8 buff[MAX_BPF_STACK]; }; + local_lock_t bh_lock; }; -static DEFINE_PER_CPU(struct bpf_scratchpad, bpf_sp); +static DEFINE_PER_CPU(struct bpf_scratchpad, bpf_sp) = { + .bh_lock = INIT_LOCAL_LOCK(bh_lock), +}; static inline int __bpf_try_make_writable(struct sk_buff *skb, unsigned int write_len) @@ -2021,6 +2024,7 @@ BPF_CALL_5(bpf_csum_diff, __be32 *, from, u32, from_size, struct bpf_scratchpad *sp = this_cpu_ptr(&bpf_sp); u32 diff_size = from_size + to_size; int i, j = 0; + __wsum ret; /* This is quite flexible, some examples: * @@ -2034,12 +2038,15 @@ BPF_CALL_5(bpf_csum_diff, __be32 *, from, u32, from_size, diff_size > sizeof(sp->diff))) return -EINVAL; + local_lock_nested_bh(&bpf_sp.bh_lock); for (i = 0; i < from_size / sizeof(__be32); i++, j++) sp->diff[j] = ~from[i]; for (i = 0; i < to_size / sizeof(__be32); i++, j++) sp->diff[j] = to[i]; - return csum_partial(sp->diff, diff_size, seed); + ret = csum_partial(sp->diff, diff_size, seed); + local_unlock_nested_bh(&bpf_sp.bh_lock); + return ret; } static const struct bpf_func_proto bpf_csum_diff_proto = { |