WARN: Cannot open record data: uftrace_524528: No such file or directory?

[m9rco]

$ uftrace --version                                                                                                                                                        130
uftrace v0.16-13-gc546 ( x86_64 dwarf python3 luajit tui perf sched dynamic kernel )

In C++11, I executed the following command through client_server:

uftrace record --data=uftrace_524528 --time client_executer # uftrace_(\d) 

client_executer has generated mcount:

$ readelf -s client_executer | grep mco
   182: 0000000000000000     0 FUNC    GLOBAL DEFAULT  UND mcount@GLIBC_2.2.5 (3)
 17569: 0000000000000000     0 FUNC    GLOBAL DEFAULT  UND mcount@@GLIBC_2.2.5

Then, the following directories were generated in the client_server directory:

drwxr-xr-x 2 root root      4096 Aug 20 10:37 uftrace_524528
drwxr-xr-x 2 root root      4096 Aug 20 10:38 uftrace_524529
drwxr-xr-x 2 root root      4096 Aug 20 10:38 uftrace_524530

I want to view information through uftrace or analyze data but cannot find the path:

uftrace info -d uftrace_524528   
WARN: cannot open record data: uftrace_524528: No such file or directory

Trying the absolute path also prompts the same:

uftrace info -d $PWD/uftrace_524528   
WARN: cannot open record data: /data/home/app/client_server/bin/uftrace_524528: No such file or directory

However, this directory truly exists:

ls /data/home/app/client_server/bin/uftrace_524528

total 437M
-rw-r--r-- 1 root root 435M Aug 20 10:47 2206632.dat
-rw-rw-rw- 1 root root    0 Aug 20 10:37 default.opts
-rw-rw-rw- 1 root root  80K Aug 20 10:47 perf-cpu0.dat
-rw-rw-rw- 1 root root  80K Aug 20 10:47 perf-cpu10.dat
-rw-rw-rw- 1 root root  40K Aug 20 10:42 perf-cpu11.dat
-rw-rw-rw- 1 root root  80K Aug 20 10:46 perf-cpu12.dat
-rw-rw-rw- 1 root root  80K Aug 20 10:46 perf-cpu13.dat
-rw-rw-rw- 1 root root  88K Aug 20 10:47 perf-cpu14.dat
-rw-rw-rw- 1 root root  48K Aug 20 10:43 perf-cpu15.dat
-rw-rw-rw- 1 root root  80K Aug 20 10:47 perf-cpu16.dat
-rw-rw-rw- 1 root root  80K Aug 20 10:47 perf-cpu17.dat
-rw-rw-rw- 1 root root  80K Aug 20 10:47 perf-cpu18.dat
-rw-rw-rw- 1 root root  64K Aug 20 10:45 perf-cpu19.dat
-rw-rw-rw- 1 root root  80K Aug 20 10:47 perf-cpu1.dat
-rw-rw-rw- 1 root root  72K Aug 20 10:46 perf-cpu20.dat
-rw-rw-rw- 1 root root  80K Aug 20 10:46 perf-cpu21.dat
-rw-rw-rw- 1 root root  72K Aug 20 10:46 perf-cpu22.dat
-rw-rw-rw- 1 root root  64K Aug 20 10:45 perf-cpu23.dat
-rw-rw-rw- 1 root root  80K Aug 20 10:47 perf-cpu24.dat
-rw-rw-rw- 1 root root  80K Aug 20 10:47 perf-cpu25.dat
-rw-rw-rw- 1 root root  88K Aug 20 10:47 perf-cpu26.dat
-rw-rw-rw- 1 root root  40K Aug 20 10:42 perf-cpu27.dat
-rw-rw-rw- 1 root root  80K Aug 20 10:46 perf-cpu28.dat
-rw-rw-rw- 1 root root  80K Aug 20 10:47 perf-cpu29.dat
-rw-rw-rw- 1 root root  88K Aug 20 10:47 perf-cpu2.dat
-rw-rw-rw- 1 root root  80K Aug 20 10:47 perf-cpu30.dat
-rw-rw-rw- 1 root root  56K Aug 20 10:44 perf-cpu31.dat
-rw-rw-rw- 1 root root  80K Aug 20 10:47 perf-cpu3.dat
-rw-rw-rw- 1 root root  80K Aug 20 10:47 perf-cpu4.dat
-rw-rw-rw- 1 root root  72K Aug 20 10:47 perf-cpu5.dat
-rw-rw-rw- 1 root root  72K Aug 20 10:47 perf-cpu6.dat
-rw-rw-rw- 1 root root  48K Aug 20 10:43 perf-cpu7.dat
-rw-rw-rw- 1 root root  80K Aug 20 10:47 perf-cpu8.dat
-rw-rw-rw- 1 root root  80K Aug 20 10:47 perf-cpu9.dat
-rw-rw-rw- 1 root root 2.5K Aug 20 10:37 sid-8291393f2d0d1620.map
-rw-rw-rw- 1 root root 245K Aug 20 10:38 task.txt

sequenceDiagram
    participant client_server
    participant client_executer
    participant uftrace

    client_server->>client_executer: creates
    client_executer->>uftrace: monitored by uftrace --time --data uftrace_*
    uftrace->>uftrace: generates uftrace_* directory

Loading

[namhyung]

Strange.. uftrace data directories should have info file in them and that's the first file uftrace opens. Have you finished your target program properly?

[m9rco]

@namhyung Yes，and there are files in this directory, do I need to upload the file content? Is there any debugging path?

1.2G    uftrace_524528
1.2G    uftrace_524529
1.2G    uftrace_524530

uftrace info -vv -d $PWD/uftrace_524528

uftrace: cannot open uftrace_524528/info file
WARN: cannot open record data: uftrace_524528: No such file or directory

(END)

My program is launched through client_server (a daemon), and then client_executer (which is also a daemon and started via command line) is initiated. I'm not sure if this call path has an impact, but it actually generated a uftrace_(\d) folder. However, strangely, the command prompt indicates that it cannot find the folder.

[m9rco]

uftrace/utils/data-file.c

Lines 371 to 391 in 7e07a43

	if (!strcmp(opts->dirname, UFTRACE_DIR_NAME)) {
	/* try again inside the current directory */
	fp = fopen("./info", "rb");
	if (fp != NULL) {
	opts->dirname = "./";
	goto ok;
	}
	/* retry with old default dirname */
	snprintf(buf, sizeof(buf), "%s/info", UFTRACE_DIR_OLD_NAME);
	fp = fopen(buf, "rb");
	if (fp != NULL) {
	opts->dirname = UFTRACE_DIR_OLD_NAME;
	goto ok;
	}
	saved_errno = errno;
	/* restore original file name for error reporting */
	snprintf(buf, sizeof(buf), "%s/info", opts->dirname);
	}

It looks like it seems to have failed to generate the file info.

uftrace/utils/data-file.c

Line 394 in 7e07a43

pr_dbg("cannot open %s file\n", buf);

When I uftrace record, I add some logs for reference, but the trouble is that it's not very convenient for me to see the supplemented logs.

[m9rco]

Strange.. uftrace data directories should have info file in them and that's the first file uftrace opens. Have you finished your target program properly?

soga~ It looks like what caused it not to be generated? Or was it deleted without reason?

[m9rco]

I'm really sorry, I think it must be my usage error, perhaps I don't understand uftrace well enough. I found that after I killed the program with kill -15 $(uftrace exec), I was able to fully generate uftrace/info.

[namhyung]

No problem! Glad to see it works and thanks for the report! :)