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 83104374ED for ; Mon, 20 Nov 2023 20:36:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2022BC433C8; Mon, 20 Nov 2023 20:36:10 +0000 (UTC) Date: Mon, 20 Nov 2023 15:36:23 -0500 From: Steven Rostedt To: Naresh Kamboju Cc: linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org, mhiramat@kernel.org, mark.rutland@arm.com, lkft@linaro.org Subject: Re: selftests: ftrace: WARNING: __list_del_entry_valid_or_report (lib/list_debug.c:62 (discriminator 1)) Message-ID: <20231120153623.49c5119b@gandalf.local.home> In-Reply-To: <20231116123016.140576-1-naresh.kamboju@linaro.org> References: <20231116123016.140576-1-naresh.kamboju@linaro.org> X-Mailer: Claws Mail 3.19.1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 16 Nov 2023 18:00:16 +0530 Naresh Kamboju wrote: > Following kernel crash noticed while running selftests: ftrace on arm64 Juno-r2 > device running stable-rc linux-6.6.y kernel. > > This kernel crash is hard to reproduce. > Can you test this patch. Note, there's a similar bug on 6.7-rc1 which I'll fix first. And when that's accepted, I'll push this one for v6.6. This may be two patches as one if the d_invalidate() issue, and another is a memory leak fix. -- Steve diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c index 5fcfb634fec2..b60048469df1 100644 --- a/fs/tracefs/event_inode.c +++ b/fs/tracefs/event_inode.c @@ -289,6 +289,8 @@ void eventfs_set_ef_status_free(struct tracefs_inode *ti, struct dentry *dentry) ef = dentry->d_fsdata; if (ef) free_ef(ef); + else + kfree(ei); return; } @@ -342,7 +344,6 @@ static void eventfs_post_create_dir(struct eventfs_file *ef) static struct dentry * create_dentry(struct eventfs_file *ef, struct dentry *parent, bool lookup) { - bool invalidate = false; struct dentry *dentry; mutex_lock(&eventfs_mutex); @@ -387,23 +388,24 @@ create_dentry(struct eventfs_file *ef, struct dentry *parent, bool lookup) eventfs_post_create_dir(ef); dentry->d_fsdata = ef; } else { - /* A race here, should try again (unless freed) */ - invalidate = true; - /* + * If we are here then the directory is being freed. + * The simple_recursive_removal() will get rid of the dentry + * here. + */ + dentry = NULL; + /* * Should never happen unless we get here due to being freed. * Otherwise it means two dentries exist with the same name. */ WARN_ON_ONCE(!ef->is_freed); } mutex_unlock(&eventfs_mutex); - if (invalidate) - d_invalidate(dentry); - if (lookup || invalidate) + if (lookup) dput(dentry); - return invalidate ? NULL : dentry; + return dentry; } static bool match_event_file(struct eventfs_file *ef, const char *name) -- 2.42.0