| Message ID | 20230703042853.1427493-1-tz.stoyanov@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | cf0a624dc706c306294c14e6b3e7694702f25191 |
| Delegated to: | Masami Hiramatsu |
| Headers | show |
| Series | [v3] kernel/trace: Fix cleanup logic of enable_trace_eprobe | expand |
On Mon, 3 Jul 2023 07:28:53 +0300 "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote: > The enable_trace_eprobe() function enables all event probes, attached > to given trace probe. If an error occurs in enabling one of the event > probes, all others should be roll backed. There is a bug in that roll > back logic - instead of all event probes, only the failed one is > disabled. This looks good to me. Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Thank you, > > Reported-by: Dan Carpenter <dan.carpenter@linaro.org> > Fixes: 7491e2c44278 ("tracing: Add a probe that attaches to trace events") > Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com> > --- > Changes since v1: https://lore.kernel.org/all/20230628121811.338655-1-tz.stoyanov@gmail.com/ > - Added one-time warning, suggested by Steven Rostedt. > Changed since v2: https://lore.kernel.org/lkml/20230630121627.833560-1-tz.stoyanov@gmail.com/ > - Added counter of successfully enabled eprobes, suggested by Steven Rostedt. > > kernel/trace/trace_eprobe.c | 18 ++++++++++++++++-- > 1 file changed, 16 insertions(+), 2 deletions(-) > > diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c > index cb0077ba2b49..a0a704ba27db 100644 > --- a/kernel/trace/trace_eprobe.c > +++ b/kernel/trace/trace_eprobe.c > @@ -644,6 +644,7 @@ static int enable_trace_eprobe(struct trace_event_call *call, > struct trace_eprobe *ep; > bool enabled; > int ret = 0; > + int cnt = 0; > > tp = trace_probe_primary_from_call(call); > if (WARN_ON_ONCE(!tp)) > @@ -667,12 +668,25 @@ static int enable_trace_eprobe(struct trace_event_call *call, > if (ret) > break; > enabled = true; > + cnt++; > } > > if (ret) { > /* Failed to enable one of them. Roll back all */ > - if (enabled) > - disable_eprobe(ep, file->tr); > + if (enabled) { > + /* > + * It's a bug if one failed for something other than memory > + * not being available but another eprobe succeeded. > + */ > + WARN_ON_ONCE(ret != -ENOMEM); > + > + list_for_each_entry(pos, trace_probe_probe_list(tp), list) { > + ep = container_of(pos, struct trace_eprobe, tp); > + disable_eprobe(ep, file->tr); > + if (!--cnt) > + break; > + } > + } > if (file) > trace_probe_remove_file(tp, file); > else > -- > 2.41.0 >
On Mon, 3 Jul 2023 07:28:53 +0300 "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote: > The enable_trace_eprobe() function enables all event probes, attached > to given trace probe. If an error occurs in enabling one of the event > probes, all others should be roll backed. There is a bug in that roll > back logic - instead of all event probes, only the failed one is > disabled. > > Reported-by: Dan Carpenter <dan.carpenter@linaro.org> > Fixes: 7491e2c44278 ("tracing: Add a probe that attaches to trace events") > Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Thanks Tzvetomir! -- Steve > --- > Changes since v1: https://lore.kernel.org/all/20230628121811.338655-1-tz.stoyanov@gmail.com/ > - Added one-time warning, suggested by Steven Rostedt. > Changed since v2: https://lore.kernel.org/lkml/20230630121627.833560-1-tz.stoyanov@gmail.com/ > - Added counter of successfully enabled eprobes, suggested by Steven Rostedt. > > kernel/trace/trace_eprobe.c | 18 ++++++++++++++++-- > 1 file changed, 16 insertions(+), 2 deletions(-) > > diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c > index cb0077ba2b49..a0a704ba27db 100644 > --- a/kernel/trace/trace_eprobe.c > +++ b/kernel/trace/trace_eprobe.c > @@ -644,6 +644,7 @@ static int enable_trace_eprobe(struct trace_event_call *call, > struct trace_eprobe *ep; > bool enabled; > int ret = 0; > + int cnt = 0; > > tp = trace_probe_primary_from_call(call); > if (WARN_ON_ONCE(!tp)) > @@ -667,12 +668,25 @@ static int enable_trace_eprobe(struct trace_event_call *call, > if (ret) > break; > enabled = true; > + cnt++; > } > > if (ret) { > /* Failed to enable one of them. Roll back all */ > - if (enabled) > - disable_eprobe(ep, file->tr); > + if (enabled) { > + /* > + * It's a bug if one failed for something other than memory > + * not being available but another eprobe succeeded. > + */ > + WARN_ON_ONCE(ret != -ENOMEM); > + > + list_for_each_entry(pos, trace_probe_probe_list(tp), list) { > + ep = container_of(pos, struct trace_eprobe, tp); > + disable_eprobe(ep, file->tr); > + if (!--cnt) > + break; > + } > + } > if (file) > trace_probe_remove_file(tp, file); > else
diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c index cb0077ba2b49..a0a704ba27db 100644 --- a/kernel/trace/trace_eprobe.c +++ b/kernel/trace/trace_eprobe.c @@ -644,6 +644,7 @@ static int enable_trace_eprobe(struct trace_event_call *call, struct trace_eprobe *ep; bool enabled; int ret = 0; + int cnt = 0; tp = trace_probe_primary_from_call(call); if (WARN_ON_ONCE(!tp)) @@ -667,12 +668,25 @@ static int enable_trace_eprobe(struct trace_event_call *call, if (ret) break; enabled = true; + cnt++; } if (ret) { /* Failed to enable one of them. Roll back all */ - if (enabled) - disable_eprobe(ep, file->tr); + if (enabled) { + /* + * It's a bug if one failed for something other than memory + * not being available but another eprobe succeeded. + */ + WARN_ON_ONCE(ret != -ENOMEM); + + list_for_each_entry(pos, trace_probe_probe_list(tp), list) { + ep = container_of(pos, struct trace_eprobe, tp); + disable_eprobe(ep, file->tr); + if (!--cnt) + break; + } + } if (file) trace_probe_remove_file(tp, file); else
The enable_trace_eprobe() function enables all event probes, attached to given trace probe. If an error occurs in enabling one of the event probes, all others should be roll backed. There is a bug in that roll back logic - instead of all event probes, only the failed one is disabled. Reported-by: Dan Carpenter <dan.carpenter@linaro.org> Fixes: 7491e2c44278 ("tracing: Add a probe that attaches to trace events") Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com> --- Changes since v1: https://lore.kernel.org/all/20230628121811.338655-1-tz.stoyanov@gmail.com/ - Added one-time warning, suggested by Steven Rostedt. Changed since v2: https://lore.kernel.org/lkml/20230630121627.833560-1-tz.stoyanov@gmail.com/ - Added counter of successfully enabled eprobes, suggested by Steven Rostedt. kernel/trace/trace_eprobe.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-)