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* [PATCH] tracing/probe: fix memleak in fetch_op_data operations
@ 2020-06-15 14:30 Vamshi K Sthambamkadi
  2020-06-15 21:13 ` Steven Rostedt
  2020-06-16  8:41 ` Masami Hiramatsu
  0 siblings, 2 replies; 7+ messages in thread
From: Vamshi K Sthambamkadi @ 2020-06-15 14:30 UTC (permalink / raw)
  To: rostedt; +Cc: mingo, linux-kernel

kmemleak report:
    [<57dcc2ca>] __kmalloc_track_caller+0x139/0x2b0
    [<f1c45d0f>] kstrndup+0x37/0x80
    [<f9761eb0>] parse_probe_arg.isra.7+0x3cc/0x630
    [<055bf2ba>] traceprobe_parse_probe_arg+0x2f5/0x810
    [<655a7766>] trace_kprobe_create+0x2ca/0x950
    [<4fc6a02a>] create_or_delete_trace_kprobe+0xf/0x30
    [<6d1c8a52>] trace_run_command+0x67/0x80
    [<be812cc0>] trace_parse_run_command+0xa7/0x140
    [<aecfe401>] probes_write+0x10/0x20
    [<2027641c>] __vfs_write+0x30/0x1e0
    [<6a4aeee1>] vfs_write+0x96/0x1b0
    [<3517fb7d>] ksys_write+0x53/0xc0
    [<dad91db7>] __ia32_sys_write+0x15/0x20
    [<da347f64>] do_syscall_32_irqs_on+0x3d/0x260
    [<fd0b7e7d>] do_fast_syscall_32+0x39/0xb0
    [<ea5ae810>] entry_SYSENTER_32+0xaf/0x102

Post parse_probe_arg(), the FETCH_OP_DATA operation type is overwritten
to FETCH_OP_ST_STRING, as a result memory is never freed since
traceprobe_free_probe_arg() iterates only over SYMBOL and DATA op types

Setup fetch string operation correctly after fetch_op_data operation.

Signed-off-by: Vamshi K Sthambamkadi <vamshi.k.sthambamkadi@gmail.com>
---
 kernel/trace/trace_probe.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index b8a928e..d2867cc 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -639,8 +639,8 @@ static int traceprobe_parse_probe_arg_body(char *arg, ssize_t *size,
 			ret = -EINVAL;
 			goto fail;
 		}
-		if ((code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM) ||
-		     parg->count) {
+		if ((code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM ||
+		     code->op == FETCH_OP_DATA) || parg->count) {
 			/*
 			 * IMM, DATA and COMM is pointing actual address, those
 			 * must be kept, and if parg->count != 0, this is an
-- 
2.7.4


^ permalink raw reply	[flat|nested] 7+ messages in thread
* Re: [PATCH] tracing/probe: fix memleak in fetch_op_data operations
@ 2020-06-15 15:10 Markus Elfring
  0 siblings, 0 replies; 7+ messages in thread
From: Markus Elfring @ 2020-06-15 15:10 UTC (permalink / raw)
  To: Vamshi K Sthambamkadi, Ingo Molnar, Steven Rostedt
  Cc: linux-kernel, kernel-janitors

…
> Post parse_probe_arg(), the FETCH_OP_DATA operation type is overwritten
> to FETCH_OP_ST_STRING, as a result memory is never freed …

How do you think about to use the term “memory leak” in the patch subject?

Will the tag “Fixes” become helpful for the commit message?

Regards,
Markus

^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, back to index

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-06-15 14:30 [PATCH] tracing/probe: fix memleak in fetch_op_data operations Vamshi K Sthambamkadi
2020-06-15 21:13 ` Steven Rostedt
2020-06-16  8:46   ` Masami Hiramatsu
2020-06-16 14:19     ` Oleg Nesterov
2020-06-16 16:21       ` Srikar Dronamraju
2020-06-16  8:41 ` Masami Hiramatsu
2020-06-15 15:10 Markus Elfring

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