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=1793210899; b=3WXb8uy2FlTi4Wa5Dd6sivfyUPHnFLGHdDK68JK95WzdoXzEowezZXMH/IdVXW7iAVRN 6ZJlfdFyyR/UEgFnZqWT9B+aCo7ybRcoBChap4MPkIZp6C3r7J5UvPlirTDR3zzrRgmB8 IqNqWl1q4/c7VtJQBtcYyAA9cyLWoYkRAPWupdHpfF3fTZciI2a+JAK6Kj+wxXfRvejtV 2dlMrDn2cZ88BJotVvgQlDzsr/W1mFuxYZ0NiHbDExxtxJ2aDr+ceTrVCJHmo/TinYshq P3ZH2lltU/U10eEeiug8UJHqPdKE/80OBWginMDOzNBC7vi+fY5T/q/4k2Ihp/TJHGg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793210899; 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=gwi+RKfDMZcDqNHSly+kdBXR+fUmZ+SnIEUQjpwsOpY=; b=h0k47tBvekaZ8zjdbJkrWLVRE28oCV76VEoX0Oj/hE/DSFXyAkRMmW275viloJNh3iJE UcTCIO2sQDZTswjM3xlfbu9PBJMOIm9QBeWDCY9pe+QxT2ngq0gtvumEJJNHNYZm5K8/X 3I9VhV6Ub0o1J7Om5Q7AkTMSWQ7B3meN9LZjLQHu6AZfycb2CeA1VW9vco/DDhOBYHtZW PHwyLu4AOuoQno1do34or5kdx17ggAnJHf8rR9sbTc7bEgKhDqvwVv9yN38lRLZ4nYccM okfcRDtAvRWJBHQe74fbtBhIa7ZmGwoLzKAbtrkUYq1uriv2zoXRceAmbWFKuQTx0kQ== 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=nbNFoSpS; 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 9C6BF606A31A; Wed, 28 Oct 2026 18:08:19 +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=nbNFoSpS Received: by smtp.kernel.org (Postfix) with ESMTPSA id B88771F01825; Wed, 28 Oct 2026 18:08:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793210899; bh=gwi+RKfDMZcDqNHSly+kdBXR+fUmZ+SnIEUQjpwsOpY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=nbNFoSpSrETBDC2f/FVu7E6LNPE87dpmNHHZfzO/20AIw/Wo9Osaky8mjLLxRXsfw KeAY9wnUcQBb+GLT4fNJlzX92CsdaPWiRgBIqBteVXX2YdIN+4/e24xSNV+zCVNSff JsCosUsMahS5JNctx5JM3dbr0HcdOSe9/fI/lYvw= 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 5.15 189/571] perf: Fix race between perf_event_exit_task() and perf_pending_task() Date: Wed, 28 Oct 2026 17:55:36 +0100 Message-ID: <20261028170012.495509330@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028170008.009143722@linuxfoundation.org> References: <20261028170008.009143722@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 5.15-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 40d31c3e1eb7a..e350e8d1fb188 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6692,9 +6692,11 @@ 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