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authorSascha Ortmann <sascha.ortmann@stud.uni-hannover.de>2020-06-18 18:33:01 +0200
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2020-06-23 21:51:50 -0400
commit20dc3847cc2fc886ee4eb9112e6e2fad9419b0c7 (patch)
tree5d576c0db4095400b0d3ec3403304936a9bc6966 /kernel
parent6784beada631800f2c5afd567e5628c843362cee (diff)
tracing/boottime: Fix kprobe multiple events
Fix boottime kprobe events to report and abort after each failure when adding probes. As an example, when we try to set multiprobe kprobe events in bootconfig like this: ftrace.event.kprobes.vfsevents { probes = "vfs_read $arg1 $arg2,, !error! not reported;?", // leads to error "vfs_write $arg1 $arg2" } This will not work as expected. After commit da0f1f4167e3af69e ("tracing/boottime: Fix kprobe event API usage"), the function trace_boot_add_kprobe_event will not produce any error message when adding a probe fails at kprobe_event_gen_cmd_start. Furthermore, we continue to add probes when kprobe_event_gen_cmd_end fails (and kprobe_event_gen_cmd_start did not fail). In this case the function even returns successfully when the last call to kprobe_event_gen_cmd_end is successful. The behaviour of reporting and aborting after failures is not consistent. The function trace_boot_add_kprobe_event now reports each failure and stops adding probes immediately. Link: https://lkml.kernel.org/r/20200618163301.25854-1-sascha.ortmann@stud.uni-hannover.de Cc: stable@vger.kernel.org Cc: linux-kernel@i4.cs.fau.de Co-developed-by: Maximilian Werner <maximilian.werner96@gmail.com> Fixes: da0f1f4167e3 ("tracing/boottime: Fix kprobe event API usage") Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Maximilian Werner <maximilian.werner96@gmail.com> Signed-off-by: Sascha Ortmann <sascha.ortmann@stud.uni-hannover.de> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace_boot.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
index 8b5490cb02bb..fa0fc08c6ef8 100644
--- a/kernel/trace/trace_boot.c
+++ b/kernel/trace/trace_boot.c
@@ -101,12 +101,16 @@ trace_boot_add_kprobe_event(struct xbc_node *node, const char *event)
kprobe_event_cmd_init(&cmd, buf, MAX_BUF_LEN);
ret = kprobe_event_gen_cmd_start(&cmd, event, val);
- if (ret)
+ if (ret) {
+ pr_err("Failed to generate probe: %s\n", buf);
break;
+ }
ret = kprobe_event_gen_cmd_end(&cmd);
- if (ret)
+ if (ret) {
pr_err("Failed to add probe: %s\n", buf);
+ break;
+ }
}
return ret;