From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 C3FBC1DF75C for ; Fri, 12 Dec 2025 01:10:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765501833; cv=none; b=NEm6TX2dhEHM4WLzPVV4WDISDBW4k2+57MZIxSpfFuINIi/4ss0qwDnRh/24JxVZjwESyqt+lQhKzhqLYwBTNctlBoL6MamVn8H6rgpQ6c/T0e6hIyqQpI+UlLJAoZahosgf7fZjkEwqXDtK1ej8aIk1fE+W9s3YD+nw7AjUw4M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765501833; c=relaxed/simple; bh=sw1U5Mfb1ZMDNSsvbYhIlqmrQbh37PU+rQKqE3CxzNw=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=pmtO6deAy/ilICPJpYhHKn/PMLDq5dHxDum4KGV0MvX60Z5bX+RjnaGaVJ8VnWKMf0XEl9v/97VQkPLRRAySSi+sPzeuiRg7WDad+LpqtIqJyTDQecabYuUw8CutjQjyxM06V1rortmWtvTFUeksEB4Hqen3CssSBmCBx/lLgaQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=Ao5RULeb; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=EGpwO8/c; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="Ao5RULeb"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="EGpwO8/c" From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1765501824; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=jti70Q/7Q1AvZq8q8ZHE0U+7Ot1babJ+rR/jp/8JxWo=; b=Ao5RULebgtzJ0NYYVFqmzMMCxvBSdF8tFHEDgLDN2PGYRhCkzfp5Vgt6ajErKtmJymkBim RtV31niAqBkCEqIY2sYVBocAOBq8DTd1rdw8bWitgo5P/2HadbSqZGRGamYwcTPtRLJTVz +lnIIMj1EfAM2thASiuAmmjuavDIcrwL20HfsTosuVxc8xfzYxJnJ7xKRDb4xpjQIcn4+s j++H1H2qjVXhevpMg9sDjxH2NiSCiJ8KU7GGF6xA1YLCH/nsWdM+IgPUHdOlBXSQdYDvCm 81VvbzOIJRno09JkHfdUeA2ZvsaAYmxpuRmaHYkCptcaDhHo6yN13U6K2ns+3A== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1765501824; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=jti70Q/7Q1AvZq8q8ZHE0U+7Ot1babJ+rR/jp/8JxWo=; b=EGpwO8/cf2SAnnSiTaCeGr/F6m18RWOhzGUcLIP/7y/7A/Orv5rT3hNSE3eqmc5HBrPMHQ l0IdWGkAswfQIVDw== To: "Kumar, Kaushlendra" , "peterz@infradead.org" Cc: "linux-kernel@vger.kernel.org" Subject: RE: [PATCH] smpboot: Add NULL check before kthread_unpark() In-Reply-To: References: <20251124051144.1427596-1-kaushlendra.kumar@intel.com> <877buug79m.ffs@tglx> Date: Fri, 12 Dec 2025 10:10:19 +0900 Message-ID: <87zf7oec90.ffs@tglx> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Wed, Dec 10 2025 at 08:21, Kaushlendra Kumar wrote: > On Mon, Nov 24 2025, Thomas Gleixner wrote: >> On Mon, Nov 24 2025 at 10:41, Kaushlendra Kumar wrote: >>> Add NULL check for tsk before calling kthread_unpark() in >>> smpboot_unpark_thread() to prevent potential null pointer dereference. >> >> How is that ever going to be NULL? > Thanks for the review. > Here I was only concerned about edge cases during CPU hotplug state transitions. Then describe your concern and the edge cases in detail. Thanks, tglx