Re: [PATCH] traing: Fix memory leak of iter->temp when reading trace_pipe
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2023-07-13 14:34:05
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On Thu, 13 Jul 2023 22:14:35 +0800 Zheng Yejian [off-list ref] wrote:
kmemleak reports:
unreferenced object 0xffff88814d14e200 (size 256):
comm "cat", pid 336, jiffies 4294871818 (age 779.490s)
hex dump (first 32 bytes):
04 00 01 03 00 00 00 00 08 00 00 00 00 00 00 00 ................
0c d8 c8 9b ff ff ff ff 04 5a ca 9b ff ff ff ff .........Z......
backtrace:
[<ffffffff9bdff18f>] __kmalloc+0x4f/0x140
[<ffffffff9bc9238b>] trace_find_next_entry+0xbb/0x1d0
[<ffffffff9bc9caef>] trace_print_lat_context+0xaf/0x4e0
[<ffffffff9bc94490>] print_trace_line+0x3e0/0x950
[<ffffffff9bc95499>] tracing_read_pipe+0x2d9/0x5a0
[<ffffffff9bf03a43>] vfs_read+0x143/0x520
[<ffffffff9bf04c2d>] ksys_read+0xbd/0x160
[<ffffffff9d0f0edf>] do_syscall_64+0x3f/0x90
[<ffffffff9d2000aa>] entry_SYSCALL_64_after_hwframe+0x6e/0xd8
when reading file 'trace_pipe', 'iter->temp' is allocated or relocated
in trace_find_next_entry() but not freed before 'trace_pipe' is closed.
To fix it, free 'iter->temp' in tracing_release_pipe().
Signed-off-by: Zheng Yejian <redacted>Why is it that every time I send a pull request to Linus, I get another fix??? Anyway, Linus, hold off. I'll send a v3 with this included as well. -- Steve
quoted hunk ↗ jump to hunk
--- kernel/trace/trace.c | 1 + 1 file changed, 1 insertion(+)diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 4529e264cb86..94cfaa884578 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c@@ -6764,6 +6764,7 @@ static int tracing_release_pipe(struct inode *inode, struct file *file) free_cpumask_var(iter->started); kfree(iter->fmt); + kfree(iter->temp); mutex_destroy(&iter->mutex); kfree(iter);