2022-11-07 11:03:52

by wangyufen

[permalink] [raw]
Subject: [PATCH v2] tracing: fix memory leak in tracing_read_pipe

kmemleak reports this issue:

unreferenced object 0xffff888105a18900 (size 128):
comm "test_progs", pid 18933, jiffies 4336275356 (age 22801.766s)
hex dump (first 32 bytes):
25 73 00 90 81 88 ff ff 26 05 00 00 42 01 58 04 %s......&...B.X.
03 00 00 00 02 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<00000000560143a1>] __kmalloc_node_track_caller+0x4a/0x140
[<000000006af00822>] krealloc+0x8d/0xf0
[<00000000c309be6a>] trace_iter_expand_format+0x99/0x150
[<000000005a53bdb6>] trace_check_vprintf+0x1e0/0x11d0
[<0000000065629d9d>] trace_event_printf+0xb6/0xf0
[<000000009a690dc7>] trace_raw_output_bpf_trace_printk+0x89/0xc0
[<00000000d22db172>] print_trace_line+0x73c/0x1480
[<00000000cdba76ba>] tracing_read_pipe+0x45c/0x9f0
[<0000000015b58459>] vfs_read+0x17b/0x7c0
[<000000004aeee8ed>] ksys_read+0xed/0x1c0
[<0000000063d3d898>] do_syscall_64+0x3b/0x90
[<00000000a06dda7f>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

iter->fmt alloced in
tracing_read_pipe() -> .. ->trace_iter_expand_format(), but not
freed, to fix, add free in tracing_release_pipe()

Signed-off-by: Wang Yufen <[email protected]>
---
v1 -> v2: del if (iter->fmt), free iter->fmt directly
kernel/trace/trace.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 47a44b0..f9d98e7 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6657,6 +6657,7 @@ static int tracing_release_pipe(struct inode *inode, struct file *file)
mutex_unlock(&trace_types_lock);

free_cpumask_var(iter->started);
+ kfree(iter->fmt);
mutex_destroy(&iter->mutex);
kfree(iter);

--
1.8.3.1



2022-11-07 12:02:45

by wangyufen

[permalink] [raw]
Subject: Re: [PATCH v2] tracing: fix memory leak in tracing_read_pipe


在 2022/11/7 19:04, Wang Yufen 写道:
> kmemleak reports this issue:
>
> unreferenced object 0xffff888105a18900 (size 128):
> comm "test_progs", pid 18933, jiffies 4336275356 (age 22801.766s)
> hex dump (first 32 bytes):
> 25 73 00 90 81 88 ff ff 26 05 00 00 42 01 58 04 %s......&...B.X.
> 03 00 00 00 02 00 00 00 00 00 00 00 00 00 00 00 ................
> backtrace:
> [<00000000560143a1>] __kmalloc_node_track_caller+0x4a/0x140
> [<000000006af00822>] krealloc+0x8d/0xf0
> [<00000000c309be6a>] trace_iter_expand_format+0x99/0x150
> [<000000005a53bdb6>] trace_check_vprintf+0x1e0/0x11d0
> [<0000000065629d9d>] trace_event_printf+0xb6/0xf0
> [<000000009a690dc7>] trace_raw_output_bpf_trace_printk+0x89/0xc0
> [<00000000d22db172>] print_trace_line+0x73c/0x1480
> [<00000000cdba76ba>] tracing_read_pipe+0x45c/0x9f0
> [<0000000015b58459>] vfs_read+0x17b/0x7c0
> [<000000004aeee8ed>] ksys_read+0xed/0x1c0
> [<0000000063d3d898>] do_syscall_64+0x3b/0x90
> [<00000000a06dda7f>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> iter->fmt alloced in
> tracing_read_pipe() -> .. ->trace_iter_expand_format(), but not
> freed, to fix, add free in tracing_release_pipe()
Fixes: efbbdaa22bb7 ("tracing: Show real address for trace event arguments")
> Signed-off-by: Wang Yufen <[email protected]>
> ---
> v1 -> v2: del if (iter->fmt), free iter->fmt directly
> kernel/trace/trace.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index 47a44b0..f9d98e7 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -6657,6 +6657,7 @@ static int tracing_release_pipe(struct inode *inode, struct file *file)
> mutex_unlock(&trace_types_lock);
>
> free_cpumask_var(iter->started);
> + kfree(iter->fmt);
> mutex_destroy(&iter->mutex);
> kfree(iter);
>

2022-11-07 13:45:23

by Masami Hiramatsu

[permalink] [raw]
Subject: Re: [PATCH v2] tracing: fix memory leak in tracing_read_pipe

On Mon, 7 Nov 2022 19:45:04 +0800
wangyufen <[email protected]> wrote:

>
> 在 2022/11/7 19:04, Wang Yufen 写道:
> > kmemleak reports this issue:
> >
> > unreferenced object 0xffff888105a18900 (size 128):
> > comm "test_progs", pid 18933, jiffies 4336275356 (age 22801.766s)
> > hex dump (first 32 bytes):
> > 25 73 00 90 81 88 ff ff 26 05 00 00 42 01 58 04 %s......&...B.X.
> > 03 00 00 00 02 00 00 00 00 00 00 00 00 00 00 00 ................
> > backtrace:
> > [<00000000560143a1>] __kmalloc_node_track_caller+0x4a/0x140
> > [<000000006af00822>] krealloc+0x8d/0xf0
> > [<00000000c309be6a>] trace_iter_expand_format+0x99/0x150
> > [<000000005a53bdb6>] trace_check_vprintf+0x1e0/0x11d0
> > [<0000000065629d9d>] trace_event_printf+0xb6/0xf0
> > [<000000009a690dc7>] trace_raw_output_bpf_trace_printk+0x89/0xc0
> > [<00000000d22db172>] print_trace_line+0x73c/0x1480
> > [<00000000cdba76ba>] tracing_read_pipe+0x45c/0x9f0
> > [<0000000015b58459>] vfs_read+0x17b/0x7c0
> > [<000000004aeee8ed>] ksys_read+0xed/0x1c0
> > [<0000000063d3d898>] do_syscall_64+0x3b/0x90
> > [<00000000a06dda7f>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
> >
> > iter->fmt alloced in
> > tracing_read_pipe() -> .. ->trace_iter_expand_format(), but not
> > freed, to fix, add free in tracing_release_pipe()
> Fixes: efbbdaa22bb7 ("tracing: Show real address for trace event arguments")

Oops, good catch!

Cc: [email protected]

Acked-by: Masami Hiramatsu (Google) <[email protected]>

Thank you,

> > Signed-off-by: Wang Yufen <[email protected]>
> > ---
> > v1 -> v2: del if (iter->fmt), free iter->fmt directly
> > kernel/trace/trace.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> > index 47a44b0..f9d98e7 100644
> > --- a/kernel/trace/trace.c
> > +++ b/kernel/trace/trace.c
> > @@ -6657,6 +6657,7 @@ static int tracing_release_pipe(struct inode *inode, struct file *file)
> > mutex_unlock(&trace_types_lock);
> >
> > free_cpumask_var(iter->started);
> > + kfree(iter->fmt);
> > mutex_destroy(&iter->mutex);
> > kfree(iter);
> >


--
Masami Hiramatsu (Google) <[email protected]>

2022-11-17 03:13:58

by Steven Rostedt

[permalink] [raw]
Subject: Re: [PATCH v2] tracing: fix memory leak in tracing_read_pipe

On Mon, 7 Nov 2022 22:17:10 +0900
Masami Hiramatsu (Google) <[email protected]> wrote:

> Oops, good catch!
>
> Cc: [email protected]
>
> Acked-by: Masami Hiramatsu (Google) <[email protected]>

Queued, thanks Wang and Masami!

-- Steve