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[60.156.123.150]) by smtp.gmail.com with ESMTPSA id q198sm3153032pfq.155.2019.06.28.03.56.42 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 28 Jun 2019 03:56:43 -0700 (PDT) Date: Fri, 28 Jun 2019 19:56:40 +0900 From: Takeshi Misawa To: Steven Rostedt Cc: Tom Zanussi , Ingo Molnar , linux-kernel@vger.kernel.org Subject: [PATCH v2] tracing: Fix memory leak in tracing_err_log_open() Message-ID: <20190628105640.GA1863@DESKTOP> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If tracing_err_log_open() call seq_open(), allocated memory is not freed. kmemleak report: unreferenced object 0xffff92c0781d1100 (size 128): comm "tail", pid 15116, jiffies 4295163855 (age 22.704s) hex dump (first 32 bytes): 00 f0 08 e5 c0 92 ff ff 00 10 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<000000000d0687d5>] kmem_cache_alloc+0x11f/0x1e0 [<000000003e3039a8>] seq_open+0x2f/0x90 [<000000008dd36b7d>] tracing_err_log_open+0x67/0x140 [<000000005a431ae2>] do_dentry_open+0x1df/0x3a0 [<00000000a2910603>] vfs_open+0x2f/0x40 [<0000000038b0a383>] path_openat+0x2e8/0x1690 [<00000000fe025bda>] do_filp_open+0x9b/0x110 [<00000000483a5091>] do_sys_open+0x1ba/0x260 [<00000000c558b5fd>] __x64_sys_openat+0x20/0x30 [<000000006881ec07>] do_syscall_64+0x5a/0x130 [<00000000571c2e94>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fix this by calling seq_release() in tracing_err_log_fops.release(). Signed-off-by: Takeshi Misawa --- Dear Steven Rostedt Thanks for reviewing. > Actually, I think it is safer to have the condition be: > > if (file->f_mode & FMODE_READ) > > As that would match the open. > > Can you send a v2? I send a v2 patch. Regards. --- kernel/trace/trace.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 83e08b78dbee..4122ccde6ec2 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -7126,12 +7126,24 @@ static ssize_t tracing_err_log_write(struct file *file, return count; } +static int tracing_err_log_release(struct inode *inode, struct file *file) +{ + struct trace_array *tr = inode->i_private; + + trace_array_put(tr); + + if (file->f_mode & FMODE_READ) + seq_release(inode, file); + + return 0; +} + static const struct file_operations tracing_err_log_fops = { .open = tracing_err_log_open, .write = tracing_err_log_write, .read = seq_read, .llseek = seq_lseek, - .release = tracing_release_generic_tr, + .release = tracing_err_log_release, }; static int tracing_buffers_open(struct inode *inode, struct file *filp) -- 2.17.1