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 13B3658124C; Wed, 9 Sep 2026 14:38:40 +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=1788964721; cv=none; b=Rom25uzqUI1yaTHuqE/5krllFUp8FN2GZxPfua8Prcq9AY3SISPIk+Nk+h+nHKcH08/7RKKlq6pMSxBIMYP9QCnF8Dd2rGnRLImg4GC2Sm1SHHQnLpO8ZM24rQdnXBdnLUvO5zFOByHRhoVZCu5yx3cg5EjE2YwV+aad5fgMkVg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788964721; c=relaxed/simple; bh=fCFhDMUUEF653f1JrTLQPFS82JjAjk7PBVQTZbyBfOw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=d4n0tAXA6wjHFtO5lqJz/pPgI4UgntfJhz2PmysQFZl/EF50bF0uUCkL10uS91094d4+PxxExSgbj3BHWenYtd90+idw96iTImVr7/zsj2sTISG+wn7CO7Qpt2b2nI4E+eLVY0SVTw0kfup3l6nG4KaUhZetmdQPgPWopnNzquc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=gjxV3vvc; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="gjxV3vvc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5355F1F00A3A; Wed, 9 Sep 2026 14:38:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788964719; bh=DLi0Oe92kAMBeQRogA66+UtsqwT7gatfMaHnUUjF9IM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=gjxV3vvciNepv4NF1McTW9rTgfLb5vYrZ/tmGE5FhZC5P9k+giQcnX9/X65H/iKmz G2Jxt+Hupbz/3HmEomRPIQ3w8+FCZJn6yBmC0XNhLTPpl3LSnntXU6JEyQ7X97jrX4 oCB+1eniHM09JrWMbITr+Zqe+DNW3gDDylhqEorc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jiri Olsa , Andrii Nakryiko , Sasha Levin Subject: [PATCH 6.18 482/583] bpf: Factor stackid_init function from __bpf_get_stackid Date: Wed, 9 Sep 2026 15:42:47 +0200 Message-ID: <20260909134254.532213246@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260909134237.773280130@linuxfoundation.org> References: <20260909134237.773280130@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ 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 Signed-off-by: Greg Kroah-Hartman --- kernel/bpf/stackmap.c | 95 +++++++++++++++++++++++++++++++------------------- 1 file changed, 59 insertions(+), 36 deletions(-) --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -246,33 +246,54 @@ get_callchain_entry_for_task(struct task #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 hash, id, trace_nr, trace_len, i, max_depth; u32 skip = flags & BPF_F_SKIP_FIELD_MASK; - bool user = flags & BPF_F_USER_STACK; - u64 *ips; - bool hash_matches; + u32 max_depth; if (trace->nr <= skip) /* skipping more than usable stack trace */ return -EFAULT; max_depth = stack_map_calculate_max_depth(map->value_size, stack_map_data_size(map), flags); - trace_nr = min_t(u32, trace->nr - skip, max_depth - 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 = min_t(u32, trace->nr - skip, max_depth - 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, i; + 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)) { struct bpf_stack_build_id *id_offs; @@ -282,42 +303,42 @@ static long __bpf_get_stackid(struct bpf pcpu_freelist_pop(&smap->freelist); if (unlikely(!new_bucket)) return -ENOMEM; - new_bucket->nr = trace_nr; + new_bucket->nr = stackid->nr; id_offs = (struct bpf_stack_build_id *)new_bucket->data; - for (i = 0; i < trace_nr; i++) - id_offs[i].ip = ips[i]; - stack_map_get_build_id_offset(id_offs, trace_nr, user, false /* !may_fault */); - 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) { + for (i = 0; i < stackid->nr; i++) + id_offs[i].ip = stackid->ips[i]; + stack_map_get_build_id_offset(id_offs, stackid->nr, user, false /* !may_fault */); + 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, @@ -326,6 +347,7 @@ BPF_CALL_3(bpf_get_stackid, struct pt_re u32 elem_size = stack_map_data_size(map); bool user = flags & BPF_F_USER_STACK; struct perf_callchain_entry *trace; + struct stackid stackid; bool kernel = !user; u32 max_depth; @@ -341,7 +363,7 @@ BPF_CALL_3(bpf_get_stackid, struct pt_re /* 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 = { @@ -370,6 +392,7 @@ BPF_CALL_3(bpf_get_stackid_pe, struct bp { struct perf_event *event = ctx->event; struct perf_callchain_entry *trace; + struct stackid stackid; bool kernel, user; __u64 nr_kernel; int ret; @@ -395,7 +418,7 @@ BPF_CALL_3(bpf_get_stackid_pe, struct bp if (kernel) { trace->nr = nr_kernel; - ret = __bpf_get_stackid(map, trace, flags); + ret = __bpf_get_stackid(&stackid, map, trace, flags); } else { /* user */ u64 skip = flags & BPF_F_SKIP_FIELD_MASK; @@ -404,7 +427,7 @@ BPF_CALL_3(bpf_get_stackid_pe, struct bp 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); } /* restore nr */