From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 789AE492E4C for ; Wed, 9 Sep 2026 00:25:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788913504; cv=none; b=DRvcbKiYn134VeR8CIjWNroEE4lcT2PRZZZLR8Pa+xtNOoHjFOveLDzXskjrmRe34kqP9mu6SBx+xPgfKMvsZdJT4+MZSpU6a94IugRPLQKvP1onUffh4UrIp922Zqcwa+XSxK75flRXGuEiBaKODXLWY0RfEc6UQy+PrjCvUJc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788913504; c=relaxed/simple; bh=v0yqYoFNcfQEhOJTFJttCex6V0Vqc66sbVe/hrVYfIk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=LSrMMpP/bAH3iMw3N4VfapQrNJbAEoT5UDrPwed/D8NTs2/4ykgTVG1L2bh9LZMWIp0Eo6JMdk4CYRbIR5tLJq6DkUn5SWeiVsoUtk3Byq6sQIqZBF4BuQTmQtAeKQzuNqMS2WaESn7ojHIM5/IFtWj61boaYcS7OKycMnWT3yw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fUNLGxoD; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="fUNLGxoD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DC51F1F00A3A; Wed, 9 Sep 2026 00:25:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788913503; bh=lvI7Fk7FrVuTmKc6ZqzRD6WNVZlKg/M1vVS0hp0K/O0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=fUNLGxoDHfUUgJG6X3sZs0JMjoB9kHJMcgAM4syfaZuw3uHmBJAgYQOrCSYkeTYYK vInZw3cv/cnDx5SOJMpyKvEs7JDSIqfgomwwbguVF0HSD9U+u48KZjcX7RHJ2D4McN SQUUAS0SC7um6cgwYAqvvWnvXxET2EMtKZ/BEOjDzcn0wXWdRfxSK3ktb1zY+EGEV/ Rs6ryHlgBYMAxNdYzIVddd3gv7fRZ/QZVESLS6VSH5PURzyRiqx0AGvtnwOVShVRI0 THeDECEHUs+ghOuB5pyxka7fHLwWYsDxgs5wJZ2paI6dNCGPaUBJ0aPamcVck7LCgo 5QhZLeL4BNIJA== From: Sasha Levin To: stable@vger.kernel.org Cc: Jiri Olsa , Andrii Nakryiko , Sasha Levin Subject: [PATCH 5.10.y 1/2] bpf: Factor stackid_init function from __bpf_get_stackid Date: Tue, 8 Sep 2026 20:25:00 -0400 Message-ID: <20260909002501.724832-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026090359-enhance-frostbite-43b5@gregkh> References: <2026090359-enhance-frostbite-43b5@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Jiri Olsa [ Upstream commit 15b837759a97237d647962f9943afe0d55af615a ] The new stackid_init function stores all the necessary bits for stackid trace and it will be used by other functions in following changes. Signed-off-by: Jiri Olsa Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20260803210149.296496-2-jolsa@kernel.org Stable-dep-of: 15f1bd857466 ("bpf: Disable preemption in bpf_get_stackid") Signed-off-by: Sasha Levin --- kernel/bpf/stackmap.c | 94 +++++++++++++++++++++++++++---------------- 1 file changed, 60 insertions(+), 34 deletions(-) diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index 3ec76cb5f240d..2373b7e3b222a 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -397,32 +397,54 @@ get_callchain_entry_for_task(struct task_struct *task, u32 max_depth) #endif } -static long __bpf_get_stackid(struct bpf_map *map, - struct perf_callchain_entry *trace, u64 flags) +struct stackid { + struct stack_map_bucket *bucket; + u64 *ips; + u32 nr; + u32 len; + u32 hash; + u32 id; +}; + +static int stackid_init(struct stackid *stackid, struct bpf_map *map, + struct perf_callchain_entry *trace, u64 flags) { struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map); - struct stack_map_bucket *bucket, *new_bucket, *old_bucket; u32 skip = flags & BPF_F_SKIP_FIELD_MASK; - u32 hash, id, trace_nr, trace_len; - bool user = flags & BPF_F_USER_STACK; - u64 *ips; - bool hash_matches; if (trace->nr <= skip) /* skipping more than usable stack trace */ return -EFAULT; - trace_nr = trace->nr - skip; - trace_len = trace_nr * sizeof(u64); - ips = trace->ip + skip; - hash = jhash2((u32 *)ips, trace_len / sizeof(u32), 0); - id = hash & (smap->n_buckets - 1); - bucket = READ_ONCE(smap->buckets[id]); + stackid->nr = trace->nr - skip; + stackid->len = stackid->nr * sizeof(u64); + stackid->ips = trace->ip + skip; + stackid->hash = jhash2((u32 *)stackid->ips, + stackid->len / sizeof(u32), 0); + stackid->id = stackid->hash & (smap->n_buckets - 1); + stackid->bucket = READ_ONCE(smap->buckets[stackid->id]); + return 0; +} + +static long __bpf_get_stackid(struct stackid *stackid, struct bpf_map *map, + struct perf_callchain_entry *trace, u64 flags) +{ + struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map); + struct stack_map_bucket *new_bucket, *old_bucket; + bool user = flags & BPF_F_USER_STACK; + bool hash_matches; + u32 trace_len; + int err; + + err = stackid_init(stackid, map, trace, flags); + if (err) + return err; - hash_matches = bucket && bucket->hash == hash; + hash_matches = stackid->bucket && + stackid->bucket->hash == stackid->hash; /* fast cmp */ if (hash_matches && flags & BPF_F_FAST_STACK_CMP) - return id; + return stackid->id; if (stack_map_use_build_id(map)) { /* for build_id+offset, pop a bucket before slow cmp */ @@ -430,41 +452,43 @@ static long __bpf_get_stackid(struct bpf_map *map, pcpu_freelist_pop(&smap->freelist); if (unlikely(!new_bucket)) return -ENOMEM; - new_bucket->nr = trace_nr; + new_bucket->nr = stackid->nr; stack_map_get_build_id_offset( (struct bpf_stack_build_id *)new_bucket->data, - ips, trace_nr, user); - trace_len = trace_nr * sizeof(struct bpf_stack_build_id); - if (hash_matches && bucket->nr == trace_nr && - memcmp(bucket->data, new_bucket->data, trace_len) == 0) { + stackid->ips, stackid->nr, user); + trace_len = stackid->nr * sizeof(struct bpf_stack_build_id); + if (hash_matches && stackid->bucket->nr == stackid->nr && + memcmp(stackid->bucket->data, new_bucket->data, + trace_len) == 0) { pcpu_freelist_push(&smap->freelist, &new_bucket->fnode); - return id; + return stackid->id; } - if (bucket && !(flags & BPF_F_REUSE_STACKID)) { + if (stackid->bucket && !(flags & BPF_F_REUSE_STACKID)) { pcpu_freelist_push(&smap->freelist, &new_bucket->fnode); return -EEXIST; } } else { - if (hash_matches && bucket->nr == trace_nr && - memcmp(bucket->data, ips, trace_len) == 0) - return id; - if (bucket && !(flags & BPF_F_REUSE_STACKID)) + if (hash_matches && stackid->bucket->nr == stackid->nr && + memcmp(stackid->bucket->data, stackid->ips, + stackid->len) == 0) + return stackid->id; + if (stackid->bucket && !(flags & BPF_F_REUSE_STACKID)) return -EEXIST; new_bucket = (struct stack_map_bucket *) pcpu_freelist_pop(&smap->freelist); if (unlikely(!new_bucket)) return -ENOMEM; - memcpy(new_bucket->data, ips, trace_len); + memcpy(new_bucket->data, stackid->ips, stackid->len); } - new_bucket->hash = hash; - new_bucket->nr = trace_nr; + new_bucket->hash = stackid->hash; + new_bucket->nr = stackid->nr; - old_bucket = xchg(&smap->buckets[id], new_bucket); + old_bucket = xchg(&smap->buckets[stackid->id], new_bucket); if (old_bucket) pcpu_freelist_push(&smap->freelist, &old_bucket->fnode); - return id; + return stackid->id; } BPF_CALL_3(bpf_get_stackid, struct pt_regs *, regs, struct bpf_map *, map, @@ -474,6 +498,7 @@ BPF_CALL_3(bpf_get_stackid, struct pt_regs *, regs, struct bpf_map *, map, u32 skip = flags & BPF_F_SKIP_FIELD_MASK; bool user = flags & BPF_F_USER_STACK; struct perf_callchain_entry *trace; + struct stackid stackid; bool kernel = !user; if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK | @@ -491,7 +516,7 @@ BPF_CALL_3(bpf_get_stackid, struct pt_regs *, regs, struct bpf_map *, map, /* couldn't fetch the stack trace */ return -EFAULT; - return __bpf_get_stackid(map, trace, flags); + return __bpf_get_stackid(&stackid, map, trace, flags); } const struct bpf_func_proto bpf_get_stackid_proto = { @@ -520,6 +545,7 @@ BPF_CALL_3(bpf_get_stackid_pe, struct bpf_perf_event_data_kern *, ctx, { struct perf_event *event = ctx->event; struct perf_callchain_entry *trace; + struct stackid stackid; bool kernel, user; __u64 nr_kernel; int ret; @@ -546,7 +572,7 @@ BPF_CALL_3(bpf_get_stackid_pe, struct bpf_perf_event_data_kern *, ctx, __u64 nr = trace->nr; trace->nr = nr_kernel; - ret = __bpf_get_stackid(map, trace, flags); + ret = __bpf_get_stackid(&stackid, map, trace, flags); /* restore nr */ trace->nr = nr; @@ -558,7 +584,7 @@ BPF_CALL_3(bpf_get_stackid_pe, struct bpf_perf_event_data_kern *, ctx, return -EFAULT; flags = (flags & ~BPF_F_SKIP_FIELD_MASK) | skip; - ret = __bpf_get_stackid(map, trace, flags); + ret = __bpf_get_stackid(&stackid, map, trace, flags); } return ret; } -- 2.53.0