5.15-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 4236de05a8e70..dd6a62134e7d1 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -200,6 +200,7 @@ struct bpf_map { struct mutex freeze_mutex; atomic64_t writecnt; bool free_after_mult_rcu_gp; + u64 cookie; /* write-once */ };
static inline bool map_value_has_spin_lock(const struct bpf_map *map) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 6f309248f13fc..6d4d08f57ad38 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -31,6 +31,7 @@ #include <linux/bpf-netns.h> #include <linux/rcupdate_trace.h> #include <linux/memcontrol.h> +#include <linux/cookie.h>
#define IS_FD_ARRAY(map) ((map)->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY || \ (map)->map_type == BPF_MAP_TYPE_CGROUP_ARRAY || \ @@ -43,6 +44,7 @@ #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); @@ -886,6 +888,10 @@ 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);