6.12-stable review patch. If anyone has any objections, please let me know.
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From: Daniel Borkmann daniel@iogearbox.net
[ Upstream commit 12df58ad294253ac1d8df0c9bb9cf726397a671d ]
Add a cookie to BPF maps to uniquely identify BPF maps for the timespan when the node is up. This is different to comparing a pointer or BPF map id which could get rolled over and reused.
Signed-off-by: Daniel Borkmann daniel@iogearbox.net Link: https://lore.kernel.org/r/20250730234733.530041-1-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/bpf.h | 1 + kernel/bpf/syscall.c | 6 ++++++ 2 files changed, 7 insertions(+)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 1150a595aa54c..fcf48bd746001 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -306,6 +306,7 @@ struct bpf_map { bool free_after_rcu_gp; atomic64_t sleepable_refcnt; s64 __percpu *elem_count; + u64 cookie; /* write-once */ };
static inline const char *btf_field_type_name(enum btf_field_type type) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index ab74a226e3d6d..27cacdde359e8 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -35,6 +35,7 @@ #include <linux/rcupdate_trace.h> #include <linux/memcontrol.h> #include <linux/trace_events.h> +#include <linux/cookie.h>
#include <net/netfilter/nf_bpf_link.h> #include <net/netkit.h> @@ -51,6 +52,7 @@ #define BPF_OBJ_FLAG_MASK (BPF_F_RDONLY | BPF_F_WRONLY)
DEFINE_PER_CPU(int, bpf_prog_active); +DEFINE_COOKIE(bpf_map_cookie); static DEFINE_IDR(prog_idr); static DEFINE_SPINLOCK(prog_idr_lock); static DEFINE_IDR(map_idr); @@ -1360,6 +1362,10 @@ static int map_create(union bpf_attr *attr) if (err < 0) goto free_map;
+ preempt_disable(); + map->cookie = gen_cookie_next(&bpf_map_cookie); + preempt_enable(); + atomic64_set(&map->refcnt, 1); atomic64_set(&map->usercnt, 1); mutex_init(&map->freeze_mutex);