From 2448e3493cb3874baa90725c87869455ebf11cd2 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 11 Jul 2014 21:06:38 +0200 Subject: [PATCH 1/5] tracing: instance_rmdir() leaks ftrace_event_file->filter instance_rmdir() path destroys the event files but forgets to free file->filter. Change remove_event_file_dir() to free_event_filter(). Link: http://lkml.kernel.org/p/20140711190638.GA19517@redhat.com Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Srikar Dronamraju Cc: Tom Zanussi Cc: "zhangwei(Jovi)" Cc: stable@vger.kernel.org # 3.11+ Fixes: f6a84bdc75b5 "tracing: Introduce remove_event_file_dir()" Signed-off-by: Oleg Nesterov Signed-off-by: Steven Rostedt --- kernel/trace/trace_events.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index f99e0b3bca8c..2de53628689f 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -470,6 +470,7 @@ static void remove_event_file_dir(struct ftrace_event_file *file) list_del(&file->list); remove_subsystem(file->system); + free_event_filter(file->filter); kmem_cache_free(file_cachep, file); } From 8abfb8727f4a724d31f9ccfd8013fbd16d539445 Mon Sep 17 00:00:00 2001 From: "zhangwei(Jovi)" Date: Thu, 18 Jul 2013 16:31:05 +0800 Subject: [PATCH 2/5] tracing: Add ftrace_trace_stack into __trace_puts/__trace_bputs Currently trace option stacktrace is not applicable for trace_printk with constant string argument, the reason is in __trace_puts/__trace_bputs ftrace_trace_stack is missing. In contrast, when using trace_printk with non constant string argument(will call into __trace_printk/__trace_bprintk), then trace option stacktrace is workable, this inconstant result will confuses users a lot. Link: http://lkml.kernel.org/p/51E7A7C9.9040401@huawei.com Cc: stable@vger.kernel.org # 3.10+ Signed-off-by: zhangwei(Jovi) Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index f243444a3772..a6ffc8918dda 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -466,6 +466,9 @@ int __trace_puts(unsigned long ip, const char *str, int size) struct print_entry *entry; unsigned long irq_flags; int alloc; + int pc; + + pc = preempt_count(); if (unlikely(tracing_selftest_running || tracing_disabled)) return 0; @@ -475,7 +478,7 @@ int __trace_puts(unsigned long ip, const char *str, int size) local_save_flags(irq_flags); buffer = global_trace.trace_buffer.buffer; event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc, - irq_flags, preempt_count()); + irq_flags, pc); if (!event) return 0; @@ -492,6 +495,7 @@ int __trace_puts(unsigned long ip, const char *str, int size) entry->buf[size] = '\0'; __buffer_unlock_commit(buffer, event); + ftrace_trace_stack(buffer, irq_flags, 4, pc); return size; } @@ -509,6 +513,9 @@ int __trace_bputs(unsigned long ip, const char *str) struct bputs_entry *entry; unsigned long irq_flags; int size = sizeof(struct bputs_entry); + int pc; + + pc = preempt_count(); if (unlikely(tracing_selftest_running || tracing_disabled)) return 0; @@ -516,7 +523,7 @@ int __trace_bputs(unsigned long ip, const char *str) local_save_flags(irq_flags); buffer = global_trace.trace_buffer.buffer; event = trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size, - irq_flags, preempt_count()); + irq_flags, pc); if (!event) return 0; @@ -525,6 +532,7 @@ int __trace_bputs(unsigned long ip, const char *str) entry->str = str; __buffer_unlock_commit(buffer, event); + ftrace_trace_stack(buffer, irq_flags, 4, pc); return 1; } From 5f8bf2d263a20b986225ae1ed7d6759dc4b93af9 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Tue, 15 Jul 2014 11:05:12 -0400 Subject: [PATCH 3/5] tracing: Fix graph tracer with stack tracer on other archs Running my ftrace tests on PowerPC, it failed the test that checks if function_graph tracer is affected by the stack tracer. It was. Looking into this, I found that the update_function_graph_func() must be called even if the trampoline function is not changed. This is because archs like PowerPC do not support ftrace_ops being passed by assembly and instead uses a helper function (what the trampoline function points to). Since this function is not changed even when multiple ftrace_ops are added to the code, the test that falls out before calling update_function_graph_func() will miss that the update must still be done. Call update_function_graph_function() for all calls to update_ftrace_function() Cc: stable@vger.kernel.org # 3.3+ Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 5b372e3ed675..ac9d1dad630b 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -265,12 +265,12 @@ static void update_ftrace_function(void) func = ftrace_ops_list_func; } + update_function_graph_func(); + /* If there's no change, then do nothing more here */ if (ftrace_trace_function == func) return; - update_function_graph_func(); - /* * If we are using the list function, it doesn't care * about the function_trace_ops. From f0160a5a2912267c02cfe692eac955c360de5fdf Mon Sep 17 00:00:00 2001 From: "zhangwei(Jovi)" Date: Thu, 18 Jul 2013 16:31:18 +0800 Subject: [PATCH 4/5] tracing: Add TRACE_ITER_PRINTK flag check in __trace_puts/__trace_bputs The TRACE_ITER_PRINTK check in __trace_puts/__trace_bputs is missing, so add it, to be consistent with __trace_printk/__trace_bprintk. Those functions are all called by the same function: trace_printk(). Link: http://lkml.kernel.org/p/51E7A7D6.8090900@huawei.com Cc: stable@vger.kernel.org # 3.11+ Signed-off-by: zhangwei(Jovi) Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index a6ffc8918dda..bda9621638cc 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -468,6 +468,9 @@ int __trace_puts(unsigned long ip, const char *str, int size) int alloc; int pc; + if (!(trace_flags & TRACE_ITER_PRINTK)) + return 0; + pc = preempt_count(); if (unlikely(tracing_selftest_running || tracing_disabled)) @@ -515,6 +518,9 @@ int __trace_bputs(unsigned long ip, const char *str) int size = sizeof(struct bputs_entry); int pc; + if (!(trace_flags & TRACE_ITER_PRINTK)) + return 0; + pc = preempt_count(); if (unlikely(tracing_selftest_running || tracing_disabled)) From 97b8ee845393701edc06e27ccec2876ff9596019 Mon Sep 17 00:00:00 2001 From: Martin Lau Date: Mon, 9 Jun 2014 23:06:42 -0700 Subject: [PATCH 5/5] ring-buffer: Fix polling on trace_pipe ring_buffer_poll_wait() should always put the poll_table to its wait_queue even there is immediate data available. Otherwise, the following epoll and read sequence will eventually hang forever: 1. Put some data to make the trace_pipe ring_buffer read ready first 2. epoll_ctl(efd, EPOLL_CTL_ADD, trace_pipe_fd, ee) 3. epoll_wait() 4. read(trace_pipe_fd) till EAGAIN 5. Add some more data to the trace_pipe ring_buffer 6. epoll_wait() -> this epoll_wait() will block forever ~ During the epoll_ctl(efd, EPOLL_CTL_ADD,...) call in step 2, ring_buffer_poll_wait() returns immediately without adding poll_table, which has poll_table->_qproc pointing to ep_poll_callback(), to its wait_queue. ~ During the epoll_wait() call in step 3 and step 6, ring_buffer_poll_wait() cannot add ep_poll_callback() to its wait_queue because the poll_table->_qproc is NULL and it is how epoll works. ~ When there is new data available in step 6, ring_buffer does not know it has to call ep_poll_callback() because it is not in its wait queue. Hence, block forever. Other poll implementation seems to call poll_wait() unconditionally as the very first thing to do. For example, tcp_poll() in tcp.c. Link: http://lkml.kernel.org/p/20140610060637.GA14045@devbig242.prn2.facebook.com Cc: stable@vger.kernel.org # 2.6.27 Fixes: 2a2cc8f7c4d0 "ftrace: allow the event pipe to be polled" Reviewed-by: Chris Mason Signed-off-by: Martin Lau Signed-off-by: Steven Rostedt --- kernel/trace/ring_buffer.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 7c56c3d06943..ff7027199a9a 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -616,10 +616,6 @@ int ring_buffer_poll_wait(struct ring_buffer *buffer, int cpu, struct ring_buffer_per_cpu *cpu_buffer; struct rb_irq_work *work; - if ((cpu == RING_BUFFER_ALL_CPUS && !ring_buffer_empty(buffer)) || - (cpu != RING_BUFFER_ALL_CPUS && !ring_buffer_empty_cpu(buffer, cpu))) - return POLLIN | POLLRDNORM; - if (cpu == RING_BUFFER_ALL_CPUS) work = &buffer->irq_work; else {