From: Sebastian Andrzej Siewior Date: Mon, 12 May 2025 09:27:25 +0000 (+0200) Subject: ipv6: sr: Use nested-BH locking for hmac_storage X-Git-Tag: v6.16-rc1~132^2~101^2~11 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=bc57eda646cea6a9077ba1b781bf64bc0ab836a7;p=linux-block.git ipv6: sr: Use nested-BH locking for hmac_storage hmac_storage 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: David Ahern Signed-off-by: Sebastian Andrzej Siewior Link: https://patch.msgid.link/20250512092736.229935-5-bigeasy@linutronix.de Signed-off-by: Paolo Abeni --- diff --git a/net/ipv6/seg6_hmac.c b/net/ipv6/seg6_hmac.c index bbf5b84a70fc..f78ecb6ad838 100644 --- a/net/ipv6/seg6_hmac.c +++ b/net/ipv6/seg6_hmac.c @@ -40,7 +40,14 @@ #include #include -static DEFINE_PER_CPU(char [SEG6_HMAC_RING_SIZE], hmac_ring); +struct hmac_storage { + local_lock_t bh_lock; + char hmac_ring[SEG6_HMAC_RING_SIZE]; +}; + +static DEFINE_PER_CPU(struct hmac_storage, hmac_storage) = { + .bh_lock = INIT_LOCAL_LOCK(bh_lock), +}; static int seg6_hmac_cmpfn(struct rhashtable_compare_arg *arg, const void *obj) { @@ -187,7 +194,8 @@ int seg6_hmac_compute(struct seg6_hmac_info *hinfo, struct ipv6_sr_hdr *hdr, */ local_bh_disable(); - ring = this_cpu_ptr(hmac_ring); + local_lock_nested_bh(&hmac_storage.bh_lock); + ring = this_cpu_ptr(hmac_storage.hmac_ring); off = ring; /* source address */ @@ -212,6 +220,7 @@ int seg6_hmac_compute(struct seg6_hmac_info *hinfo, struct ipv6_sr_hdr *hdr, dgsize = __do_hmac(hinfo, ring, plen, tmp_out, SEG6_HMAC_MAX_DIGESTSIZE); + local_unlock_nested_bh(&hmac_storage.bh_lock); local_bh_enable(); if (dgsize < 0)