Since @symbol variable access is not supported by uprobe event, it must be
correctly warn user instead of kernel version update.
Committer testing:
With/without the patch:
[root@quaco ~]# perf probe -x ~/bin/perf -L sigtrap_handler
<sigtrap_handler@/home/acme/git/perf-tools-next/tools/perf/tests/sigtrap.c:0>
0 sigtrap_handler(int signum __maybe_unused, siginfo_t *info, void *ucontext __maybe_unused)
1 {
2 if (!__atomic_fetch_add(&ctx.signal_count, 1, __ATOMIC_RELAXED))
3 ctx.first_siginfo = *info;
4 __atomic_fetch_sub(&ctx.tids_want_signal, syscall(SYS_gettid), __ATOMIC_RELAXED);
5 }
static void *test_thread(void *arg)
{
[root@quaco ~]# perf probe -x ~/bin/perf sigtrap_handler:4 "ctx.signal_count"
Without the patch:
[root@quaco ~]# perf probe -x ~/bin/perf sigtrap_handler:4 "ctx.signal_count"
Failed to write event: Invalid argument
Please upgrade your kernel to at least 3.14 to have access to feature @ctx
Error: Failed to add events.
[root@quaco ~]#
With the patch:
[root@quaco ~]#
Failed to write event: Invalid argument
@ctx accesses a variable by symbol name, but that is not supported for user application probe.
Error: Failed to add events.
[root@quaco ~]#
Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Closes: https://lore.kernel.org/all/ZLWDEjvFjrrEJODp@kernel.org/
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: https://lore.kernel.org/r/169055397023.67089.12693645664676964310.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
if (!tev->uprobes || tev->nargs == 0 || !buf)
goto out;
- for (i = 0; i < tev->nargs; i++)
- if (strglobmatch(tev->args[i].value, "[$@+-]*")) {
- pr_warning("Please upgrade your kernel to at least "
- "3.14 to have access to feature %s\n",
+ for (i = 0; i < tev->nargs; i++) {
+ if (strchr(tev->args[i].value, '@')) {
+ pr_warning("%s accesses a variable by symbol name, but that is not supported for user application probe.\n",
+ tev->args[i].value);
+ break;
+ }
+ if (strglobmatch(tev->args[i].value, "[$+-]*")) {
+ pr_warning("Please upgrade your kernel to at least 3.14 to have access to feature %s\n",
tev->args[i].value);
break;
}
+ }
out:
free(buf);
}