With the latest linux-next i noticed that some tests in the ftrace test suites are failing on s390, namely: [FAIL] Kprobe event symbol argument [FAIL] Kprobe event with comm arguments The following doesn't work anymore: cd /sys/kernel/tracing echo 'p:testprobe _do_fork comm=$comm ' >kprobe_events echo 1 >events/kprobes/testprobe/enable cat trace it will just show test.sh-519 [012] .... 18.580625: testprobe: (_do_fork+0x0/0x3c8) comm=(fault) Looking at the source i see that there are two helpers for reading strings: fetch_store_string_user() -> read string from user space fetch_store_string() -> read string from kernel space(?) but in the end both are using strncpy_from_user_nofault(), but fetch_store_string() should use strncpy_from_kernel_nofault(). Signed-off-by: Sven Schnelle <svens@xxxxxxxxxxxxx> Acked-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx> Acked-by: Christoph Hellwig <hch@xxxxxx> --- kernel/trace/trace_kprobe.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index b1f21d558e45..ea8d0b094f1b 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1278,7 +1278,7 @@ fetch_store_string(unsigned long addr, void *dest, void *base) * Try to get string again, since the string can be changed while * probing. */ - ret = strncpy_from_user_nofault(__dest, (void *)addr, maxlen); + ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen); if (ret >= 0) *(u32 *)dest = make_data_loc(ret, __dest - base); -- 2.17.1
