From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793212729; b=UxcgVKdHFkyMs6Bsjy2n03kMYZCRfAD1lvmCXnoFcZxZrGpaKxzxXKDmpd2yJpmZ5ZaH DG77SJqi3Z4JFwffb4y2FuVWYLxFPLslAjXmBGCOrx6ATvfx67EaU+aDavlwl4VTM7a+N KATiKk4GV6npIyQo8iErnuuOi87yE4EcPjKxND0vCuS7Y7C32i1bnFZLRl41YFYE4td3o fLOjgwNTiZPutrYhebziNdDcrEVxHXA2Gve5+iCJiN439uzzFBBU4/cOPcopJcNCYnC0a z+A3SxZNyH6unqz9Fbmb4XH/tggv9L6L8k1Q92Tlobq3vZ3tiqZBHF7tJ8s8fsZi5ng== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793212729; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=bqE9WI/fe9061zfzodDDOPuM3LipPz38cQRReDPOBrI=; b=L/3lZoiP2OOnY3JLwsBISnW3eJpIkQ2FWVLvOvJBqDADlnvAhlqAWKvcUoP/yW48i4eN dferNnLSDS3JGaOS+JYpLYQcSejQTBpz/xraj50g0qVu4zyXr51M7q20bZFm42eEjEo1d 1bUp5r2n/y2thOLsjxH4eaykjvzRsUf0UFz9TdWM1CtTWKC2NF1maF5dJDFyQdkBsZSxX 4MToOgp66n+nG9JMFXKr8uUQb/e3ejJYJzmeDsVvwAunH31f0eQ285ti/ADwvY1NF0d9I taZyHaep4KN+NzDyPPKBfRL+LQiXXeyRMeEaZlVgmhunswydDKphPI/dbqM+tsuwzpg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=RZR8+gC2; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4758C606A324; Wed, 28 Oct 2026 18:38:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=RZR8+gC2 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9A2F81F01825; Wed, 28 Oct 2026 18:38:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793212729; bh=bqE9WI/fe9061zfzodDDOPuM3LipPz38cQRReDPOBrI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=RZR8+gC2hyLd/izb/dUJ+QPIdxxzKaS/dIhM/G6C7t/UUl1PgOFbTteVL7p0eojW6 +5PzfnDxx34p5DqUdNnSxASI5HD+bMXIURycp8URPgX/NizRTiW2reGd7oT3zSaPoz UXCt7/uIDNZIkPFZGNg/xuvm8MTr5Z4IYKB9C6zA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Luo Gengkun , "Peter Zijlstra (Intel)" , Sasha Levin Subject: [PATCH 6.1 0249/1887] perf: Fix race between perf_event_exit_task() and perf_pending_task() Date: Wed, 28 Oct 2026 17:39:05 +0100 Message-ID: <20261028170504.897512394@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028170459.200466217@linuxfoundation.org> References: <20261028170459.200466217@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Luo Gengkun [ Upstream commit ffb684f2aa141eeb0caa6308422e7e05d1ded7c4 ] A race condition exists between perf_event_exit_task() and perf_pending_task() during begin_new_exec(). During begin_new_exec(), perf_event_exit_task() may be called, and the PF_EXITING flag is not set on task. So perf_sigtrap() continues to execute and triggers WARN_ON_ONCE(event->ctx->task != current). Since both task exit and exec paths can call perf_event_exit_task() which sets ctx->task to TASK_TOMBSTONE, fix this by explicitly checking if event->ctx->task equals TASK_TOMBSTONE and dropping the redundant PF_EXITING check. Fixes: 97ba62b27867 ("perf: Add support for SIGTRAP on perf events") Signed-off-by: Luo Gengkun Signed-off-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/20260920075026.990582-1-luogengkun2@huawei.com Signed-off-by: Sasha Levin --- kernel/events/core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index e5c79c55ce48e..013c3a4afb8a3 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6596,9 +6596,11 @@ static void perf_sigtrap(struct perf_event *event) { /* * Both perf_pending_task() and perf_pending_irq() can race with the - * task exiting. + * task exiting or exec-ing. We can determine if such a race has + * occurred by checking if perf_event_exit_task(), which will set + * ctx->task to TASK_TOMBSTONE, has already been called. */ - if (current->flags & PF_EXITING) + if (event->ctx->task == TASK_TOMBSTONE) return; /* -- 2.53.0