From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 D4FAD329391; Sat, 21 Mar 2026 00:54:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774054463; cv=none; b=KBPOcgQqbprSL371zm1WS9vXnc8Laj01pLEFOK17ki0l+RCwqhhURlC/wz8WaVRp6QGPBwhK8YeXj5096DccLh4lPkYOopSfIm149DZokTrw2k2z050vJThK6CJynkWQLwLgKMHJjbwqukS5g86PZRF2QAfYbsvknAsw4GQspTg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774054463; c=relaxed/simple; bh=PEeArNKfdFtHas/K96y4Ll77SY637LRRo0yTKUiZYcQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QBUBMriG91cEk/r/HW0SkvKzTNad60es1B+jvV9v1/FJdrmKgHqwxaTWdjAx8riHsa+BWCn8xTH7a6WqH0SsljkxxIwK+LQrEMwK7131cWd9I1VMR1MPSUcztoKR5B6fje0uTqlZ4BJG1Sevmxree55rVw6gSFR4CNETgtimb7g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mnrnE65Y; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mnrnE65Y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 97E51C4CEF7; Sat, 21 Mar 2026 00:54:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774054463; bh=PEeArNKfdFtHas/K96y4Ll77SY637LRRo0yTKUiZYcQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mnrnE65YuUXx6wnZe89Pe8iU5GLqPwOxRUTc/lGakGTHrXAe056KH8+F0/0eC9+hd OuSgVk6eCFkMm1LUPnYjqoGChMnSnkildU6yWNvDyW7PFu/vSK+4HKx2pBaD+xUcgQ EUrgbXRoPKLRgDaLDX/I2kverlCh6icZ2CuahrzwSOCYjG6Fr8xic5NqUrOz3CbYGo txpfW1U/R+sbbMGNi+IY/AD5mar9Wm2MNK23PGQvJ93YrALvHjotp2RmWZB7jRkqts grePXrbvJB0zhp+wP3oMY34PmU3Vt8Gt+F8MNCh9RPK7K6VdCtDT6ODEEHEXjS6Rc8 szJr8/dx/SiNg== From: SeongJae Park To: Josh Law Cc: SeongJae Park , Andrew Morton , damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v2 3/3] mm/damon/sysfs: check contexts->nr in repeat_call_fn Date: Fri, 20 Mar 2026 17:54:19 -0700 Message-ID: <20260321005420.80596-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260320163559.178101-3-objecting@objecting.org> References: Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Fri, 20 Mar 2026 16:35:59 +0000 Josh Law wrote: > damon_sysfs_repeat_call_fn() calls damon_sysfs_upd_tuned_intervals(), > damon_sysfs_upd_schemes_stats(), and > damon_sysfs_upd_schemes_effective_quotas() without checking > contexts->nr. If nr_contexts is set to 0 via sysfs while DAMON is > running, these functions dereference contexts_arr[0] and cause a NULL > pointer dereference. Add the missing check. > > Fixes: d809a7c64ba8 ("mm/damon/sysfs: implement refresh_ms file internal work") > Cc: # 6.17.x > Signed-off-by: Josh Law > Reviewed-by: SeongJae Park > --- >From the next time, please add patch changelog here. [...] Sashiko also added comments [1] that are very same as those for the previous version of this patch. I replied [2] to those on the thread. In short, nice findings but orthogonal to this patch, and I will work on those separately. [1] https://sashiko.dev/#/patchset/20260320163559.178101-3-objecting@objecting.org [2] https://lore.kernel.org/20260320020630.962-1-sj@kernel.org Thanks, SJ [...]