From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=74.125.82.198 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792622374; b=AO1zHLD0Np3AlAtxKaWoUj4trD9VBFjmrbcay7PnLcSr/8x4RxjP0tWXcDJMeKlmVCKW 1JSgghS3b4NhB3U4UYKo3qcYiRnS/RnAzraVeKoxJlTvaa9/ia0SHbYRG1fmIKtAU0+CF qVGe3SmN9aXFcBD/PC2zPj9XUfA7MhNCU6KzSD8UZlgExbammk9L+t++MsaQ/D0Axjasc PLWPSyRz5z4CUgj8r8sShV7aPWHBldGSc8JjNv9f+yD/X7ceTs15GKdz0SQLedpKhe+QJ 6nZeqC9/0Y9Bxjo2Nu+qRNp+BmzG0ABIDhczTE/3HW988kCYuux4zDyu5uYbEHGIqjw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792622374; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Received:Date:In-Reply-To: Mime-Version:References:X-Mailer:Message-ID:Subject:From:To:Cc: Content-Type; bh=8yD69uT8OzBgCMK82/DZER0A0HpZ/t80pTFtRy6AltA=; b=0EsEWf7ZXgVMXmJbaAvtxqxvtA7rLJzqHMlilrKU60eI0fNtOs5XTYktV8seE3fPNr9l PsA4JNrK0MxYf0WvwqPqIYAzIxEIAVgcYqvl9YYY7sziXrlMkAlol4O2K184S5XaixorH 0a/JLMtgAUqdFk+TsJZwy//Zk2XODFqlPRLmsoGZjg2jIoHzAvnjvTuex8Q6r2BnO7z+u tMBikPECMjDGRWXwfQwk9mzHg9MIre5ss9FAbSqYC+gMH3ZxPi+AT8YjEqf9wl19bIuRP 5gS7FEnKFr5ZS89baKTV/M7j9IHysv5uQQH6GScJU/qb7X6y2hxXgGsQPDc/waVGw9A== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=google.com; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com; dkim=pass header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20251104 header.b=fvHLyB4k; arc=none smtp.remote-ip=74.125.82.198 Received: from mail-dy1-f198.google.com (mail-dy1-f198.google.com [74.125.82.198]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BB5BE606A326 for ; Wed, 21 Oct 2026 22:39:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org BB5BE606A326 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20251104 header.b=fvHLyB4k Received: by mail-dy1-f198.google.com with SMTP id 5a478bee46e88-33c35f5ca6cso2251984eec.1 for ; Wed, 21 Oct 2026 15:39:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1792622373; x=1793227173; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=8yD69uT8OzBgCMK82/DZER0A0HpZ/t80pTFtRy6AltA=; b=fvHLyB4k4n9g/gUoYvL0mBeTV+VWZif/gpqlAvFetRV93KxALBF+etnuZF3Fadm1BW QatEEuiY6hVsxCEc2DnbJNbwlkZmSGPbdOp+Jw8Rq4DbODbQrFlcc6iBaww8ys6AoL09 cmrLg2NyLPziCppuCdBYzYChizSZrLIkN/++Otoyuksw7K0DYRm52w6svb1lgbAMAQlh ydMWiJIm9sFD4Ca1dCB/YKnDuK/HbURDfk98QdMcL8BbrpqsUNe8m1tYB+R5RCTUCymv yDfS1hw+fG1/NLysBi5E3fL5PBpho2wHnc5mFaLYzr14w6sFPGwZy7OQ33/1JUt2sN9s uK3g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1792622373; x=1793227173; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=8yD69uT8OzBgCMK82/DZER0A0HpZ/t80pTFtRy6AltA=; b=nAvb/kGEDKkfZ+QQ7FJ1BDdN7EsylzysR2ZLYXO6IAHpLp51hAZMfVA8HTkeqDv+B7 MNLFKH0RBJppKS1jf0qGalUPP6sUo+nhlHNnfvZDKBiftq0XvWZZrf7lrZj9WEwnvxXz OSCPBu91959VE4p7ONbAk7kJUBRCt1T02z4BZa67XMor71uIHx0YW4hD3msb2PTTv3A8 7OwyDEQoi+e275eR6k5H8IDn+9rm1qpGR/xJ7wInvHwmUZiBYUH8AfJf7NQTgw8+bqTE OQbhkS6A7Q0gZX88ok5/C9hxXJEYaOSOKodR1SzP5nZdsUMQvFlunwPX5p/nPtKqjZE6 143A== X-Forwarded-Encrypted: i=1; AKwUvBzZ1w4E6Q8OW2MVxdP+hA2oIXeSqhakWwc8OTEl6MAuo+SaeSgE/a3u3lLydvn0OuZcBqz6u+1b/nnqWTI=@vger.kernel.org X-Gm-Message-State: AFq9FYI/AjG+kscJ343Rat0K16PvPsBJ8pJRr+WUb4oabv5YWGqJH6Ws WNBlf25lgLe+fR3amMChCZNEbUrHaVnKx3Dj+Ps0fag+OD4Hcg1mWSl70DfWSw67IsLQ4Llj40/ VeEqLF413GA== X-Received: from dycak12.prod.google.com ([2002:a05:7301:1c0c:b0:353:82df:8a9]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a05:693c:414b:20b0:367:5e31:ce29 with SMTP id 5a478bee46e88-3675e31ce6bmr4921809eec.20.1792622372488; Wed, 21 Oct 2026 15:39:32 -0700 (PDT) Date: Wed, 21 Oct 2026 15:38:55 -0700 In-Reply-To: <20261021223905.715051-1-irogers@google.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list Mime-Version: 1.0 References: <20261021171044.155240-1-irogers@google.com> <20261021223905.715051-1-irogers@google.com> X-Mailer: git-send-email 2.56.0.218.g1ec904b173-goog Message-ID: <20261021223905.715051-8-irogers@google.com> Subject: [PATCH v7 07/17] perf vdso: Fix unlocked __dsos__add() and race in __machine__addnew_vdso() From: Ian Rogers To: irogers@google.com, acme@kernel.org, elver@google.com, namhyung@kernel.org Cc: adrian.hunter@intel.com, james.clark@linaro.org, jolsa@kernel.org, justinstitt@google.com, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, ljs@kernel.org, llvm@lists.linux.dev, mingo@redhat.com, morbo@google.com, nathan@kernel.org, ndesaulniers@google.com, peterz@infradead.org Content-Type: text/plain; charset="UTF-8" __machine__addnew_vdso() called __dsos__add(&machine->dsos, dso) without holding machine->dsos.lock, and machine__findnew_vdso() and __machine__findnew_compat() initialized machine->vdso_info and created temporary VDSO files without synchronization. Acquire machine->dsos.lock in write mode across machine->vdso_info initialization, duplicate checking via __dsos__find(), temporary file creation, dso__set_long_name(), and __dsos__add(). Signed-off-by: Ian Rogers --- tools/perf/util/dsos.c | 7 +++++- tools/perf/util/dsos.h | 1 + tools/perf/util/vdso.c | 52 +++++++++++++++++++++++++++--------------- 3 files changed, 40 insertions(+), 20 deletions(-) diff --git a/tools/perf/util/dsos.c b/tools/perf/util/dsos.c index a2cd37bd1660..40267d3a725d 100644 --- a/tools/perf/util/dsos.c +++ b/tools/perf/util/dsos.c @@ -284,12 +284,17 @@ static struct dso *__dsos__find_id(struct dsos *dsos, const char *name, const st return res; } +struct dso *__dsos__find(struct dsos *dsos, const char *name, bool cmp_short, bool write_locked) +{ + return __dsos__find_id(dsos, name, &dso_id_empty, cmp_short, write_locked); +} + struct dso *dsos__find(struct dsos *dsos, const char *name, bool cmp_short) { struct dso *res; down_read(&dsos->lock); - res = __dsos__find_id(dsos, name, &dso_id_empty, cmp_short, /*write_locked=*/false); + res = __dsos__find(dsos, name, cmp_short, /*write_locked=*/false); up_read(&dsos->lock); return res; } diff --git a/tools/perf/util/dsos.h b/tools/perf/util/dsos.h index a26774950866..857a79fd8805 100644 --- a/tools/perf/util/dsos.h +++ b/tools/perf/util/dsos.h @@ -30,6 +30,7 @@ void dsos__exit(struct dsos *dsos); int __dsos__add(struct dsos *dsos, struct dso *dso); int dsos__add(struct dsos *dsos, struct dso *dso); +struct dso *__dsos__find(struct dsos *dsos, const char *name, bool cmp_short, bool write_locked); struct dso *dsos__find(struct dsos *dsos, const char *name, bool cmp_short); struct dso *dsos__findnew_id(struct dsos *dsos, const char *name, const struct dso_id *id); diff --git a/tools/perf/util/vdso.c b/tools/perf/util/vdso.c index c12f5d8c4bf6..93828e660672 100644 --- a/tools/perf/util/vdso.c +++ b/tools/perf/util/vdso.c @@ -131,8 +131,13 @@ static struct dso *__machine__addnew_vdso(struct machine *machine, const char *s dso = dso__new(short_name); if (dso != NULL) { - __dsos__add(&machine->dsos, dso); + /* + * Set the long name before adding to machine->dsos so that + * __dsos__add() inserts it in sorted order without needing to + * re-take machine->dsos.lock. + */ dso__set_long_name(dso, long_name, false); + __dsos__add(&machine->dsos, dso); } return dso; @@ -250,15 +255,19 @@ static struct dso *__machine__findnew_compat(struct machine *machine, const char *file_name; struct dso *dso; - dso = dsos__find(&machine->dsos, vdso_file->dso_name, true); + down_write(&machine->dsos.lock); + dso = __dsos__find(&machine->dsos, vdso_file->dso_name, true, /*write_locked=*/true); if (dso) - return dso; + goto out_unlock; file_name = vdso__get_compat_file(vdso_file); if (!file_name) - return NULL; + goto out_unlock; - return __machine__addnew_vdso(machine, vdso_file->dso_name, file_name); + dso = __machine__addnew_vdso(machine, vdso_file->dso_name, file_name); +out_unlock: + up_write(&machine->dsos.lock); + return dso; } static int __machine__findnew_vdso_compat(struct machine *machine, @@ -332,33 +341,38 @@ struct dso *machine__findnew_vdso(struct machine *machine, { struct vdso_info *vdso_info; struct dso *dso = NULL; - char *file; + const char *file; + dso = machine__find_vdso(machine, thread); + if (dso) + return dso; + + down_write(&machine->dsos.lock); if (!machine->vdso_info) machine->vdso_info = vdso_info__new(); vdso_info = machine->vdso_info; - if (!vdso_info) + if (!vdso_info) { + up_write(&machine->dsos.lock); return NULL; - - dso = machine__find_vdso(machine, thread); - if (dso) - return dso; + } #if BITS_PER_LONG == 64 + up_write(&machine->dsos.lock); if (__machine__findnew_vdso_compat(machine, thread, vdso_info, &dso)) return dso; + down_write(&machine->dsos.lock); #endif - dso = dsos__find(&machine->dsos, DSO__NAME_VDSO, true); - if (dso) - return dso; - - file = get_file(&vdso_info->vdso); - if (!file) - return NULL; + dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO, true, /*write_locked=*/true); + if (!dso) { + file = get_file(&vdso_info->vdso); + if (file) + dso = __machine__addnew_vdso(machine, DSO__NAME_VDSO, file); + } + up_write(&machine->dsos.lock); - return __machine__addnew_vdso(machine, DSO__NAME_VDSO, file); + return dso; } bool dso__is_vdso(struct dso *dso) -- 2.56.0.218.g1ec904b173-goog