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| author | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2020-01-24 10:07:42 -0500 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2020-01-27 10:56:02 -0500 |
| commit | 20279420ae3a8ef4c5d9fedc360a2c37a1dbdf1b (patch) | |
| tree | 72990cd47041ddbbfb1bed4b12b662a9d54eeb4d /kernel | |
| parent | b61387cb732cf283d318b2165c44913525fe545f (diff) | |
| download | linux-20279420ae3a8ef4c5d9fedc360a2c37a1dbdf1b.tar.bz2 | |
tracing/kprobes: Have uname use __get_str() in print_fmt
Thomas Richter reported:
> Test case 66 'Use vfs_getname probe to get syscall args filenames'
> is broken on s390, but works on x86. The test case fails with:
>
> [root@m35lp76 perf]# perf test -F 66
> 66: Use vfs_getname probe to get syscall args filenames
> :Recording open file:
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 0.004 MB /tmp/__perf_test.perf.data.TCdYj\
> (20 samples) ]
> Looking at perf.data file for vfs_getname records for the file we touched:
> FAILED!
> [root@m35lp76 perf]#
The root cause was the print_fmt of the kprobe event that referenced the
"ustring"
> Setting up the kprobe event using perf command:
>
> # ./perf probe "vfs_getname=getname_flags:72 pathname=filename:ustring"
>
> generates this format file:
> [root@m35lp76 perf]# cat /sys/kernel/debug/tracing/events/probe/\
> vfs_getname/format
> name: vfs_getname
> ID: 1172
> format:
> field:unsigned short common_type; offset:0; size:2; signed:0;
> field:unsigned char common_flags; offset:2; size:1; signed:0;
> field:unsigned char common_preempt_count; offset:3; size:1; signed:0;
> field:int common_pid; offset:4; size:4; signed:1;
>
> field:unsigned long __probe_ip; offset:8; size:8; signed:0;
> field:__data_loc char[] pathname; offset:16; size:4; signed:1;
>
> print fmt: "(%lx) pathname=\"%s\"", REC->__probe_ip, REC->pathname
Instead of using "__get_str(pathname)" it referenced it directly.
Link: http://lkml.kernel.org/r/20200124100742.4050c15e@gandalf.local.home
Cc: stable@vger.kernel.org
Fixes: 88903c464321 ("tracing/probe: Add ustring type for user-space string")
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Reported-by: Thomas Richter <tmricht@linux.ibm.com>
Tested-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/trace_probe.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index 9ae87be422f2..ab8b6436d53f 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -876,7 +876,8 @@ static int __set_print_fmt(struct trace_probe *tp, char *buf, int len, for (i = 0; i < tp->nr_args; i++) { parg = tp->args + i; if (parg->count) { - if (strcmp(parg->type->name, "string") == 0) + if ((strcmp(parg->type->name, "string") == 0) || + (strcmp(parg->type->name, "ustring") == 0)) fmt = ", __get_str(%s[%d])"; else fmt = ", REC->%s[%d]"; @@ -884,7 +885,8 @@ static int __set_print_fmt(struct trace_probe *tp, char *buf, int len, pos += snprintf(buf + pos, LEN_OR_ZERO, fmt, parg->name, j); } else { - if (strcmp(parg->type->name, "string") == 0) + if ((strcmp(parg->type->name, "string") == 0) || + (strcmp(parg->type->name, "ustring") == 0)) fmt = ", __get_str(%s)"; else fmt = ", REC->%s"; |