Commit d122ed62 authored Jun 28, 2019 by Takeshi Misawa Committed by Steven Rostedt (VMware) Jun 28, 2019

tracing: Fix memory leak in tracing_err_log_open()

When tracing_err_log_open() calls 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().

Link: http://lkml.kernel.org/r/20190628105640.GA1863@DESKTOP



Fixes: 8a062902 ("tracing: Add tracing error log")
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Takeshi Misawa <jeliantsurux@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

parent 39611265

kernel/trace/trace.c

+13 −1

Original line number	Diff line number	Diff line
		@@ -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)

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