| Message ID | 20230601094158.575019-1-sunliming@kylinos.cn (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | tracing/user_events: Fix the incorrect trace record for null arguments events | expand |
On Thu, Jun 01, 2023 at 05:41:58PM +0800, sunliming wrote: > The user_events support events that has null arguments. But the trace event > is discard and not really committed when the arguments is null, fix this > problem. > Thanks for the patch, this is a good catch! Can you reword this a bit? "fix this problem" could be reworded to "Fix this by not attempting to copy in non-zero data". Would you mind adding this case to either the perf or ftrace self-test? It's a really good edge case. Thanks, -Beau > Signed-off-by: sunliming <sunliming@kylinos.cn> > --- > kernel/trace/trace_events_user.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c > index 0d91dac206ff..296bdfa674cb 100644 > --- a/kernel/trace/trace_events_user.c > +++ b/kernel/trace/trace_events_user.c > @@ -1399,7 +1399,7 @@ static void user_event_ftrace(struct user_event *user, struct iov_iter *i, > if (unlikely(!entry)) > return; > > - if (unlikely(!copy_nofault(entry + 1, i->count, i))) > + if (unlikely(i->count && !copy_nofault(entry + 1, i->count, i))) > goto discard; > > if (!list_empty(&user->validators) && > @@ -1440,7 +1440,7 @@ static void user_event_perf(struct user_event *user, struct iov_iter *i, > > perf_fetch_caller_regs(regs); > > - if (unlikely(!copy_nofault(perf_entry + 1, i->count, i))) > + if (unlikely(i->count && !copy_nofault(perf_entry + 1, i->count, i))) > goto discard; > > if (!list_empty(&user->validators) && > -- > 2.25.1
diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c index 0d91dac206ff..296bdfa674cb 100644 --- a/kernel/trace/trace_events_user.c +++ b/kernel/trace/trace_events_user.c @@ -1399,7 +1399,7 @@ static void user_event_ftrace(struct user_event *user, struct iov_iter *i, if (unlikely(!entry)) return; - if (unlikely(!copy_nofault(entry + 1, i->count, i))) + if (unlikely(i->count && !copy_nofault(entry + 1, i->count, i))) goto discard; if (!list_empty(&user->validators) && @@ -1440,7 +1440,7 @@ static void user_event_perf(struct user_event *user, struct iov_iter *i, perf_fetch_caller_regs(regs); - if (unlikely(!copy_nofault(perf_entry + 1, i->count, i))) + if (unlikely(i->count && !copy_nofault(perf_entry + 1, i->count, i))) goto discard; if (!list_empty(&user->validators) &&
The user_events support events that has null arguments. But the trace event is discard and not really committed when the arguments is null, fix this problem. Signed-off-by: sunliming <sunliming@kylinos.cn> --- kernel/trace/trace_events_user.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)