From 3a43ce68ae1758fa6a839386025ef45acb6baa22 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sat, 8 Aug 2009 04:26:37 +0200 Subject: perf_counter: Fix tracepoint sampling to be part of generic sampling Based on Peter's comments, make tracepoint sampling generic just like all the other sampling bits are. This is a rename with no code changes: - PERF_SAMPLE_TP_RECORD to PERF_SAMPLE_RAW - struct perf_tracepoint_record to perf_raw_record We want the system in place that transport tracepoints raw samples events into the perf ring buffer to be generalized and usable by any type of counter. Reported-by; Peter Zijlstra Signed-off-by: Frederic Weisbecker Cc: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Mike Galbraith Cc: Paul Mackerras LKML-Reference: <1249698400-5441-4-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar --- include/linux/perf_counter.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'include') diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h index a67dd5c5b6d..2aabe43c1d0 100644 --- a/include/linux/perf_counter.h +++ b/include/linux/perf_counter.h @@ -121,7 +121,7 @@ enum perf_counter_sample_format { PERF_SAMPLE_CPU = 1U << 7, PERF_SAMPLE_PERIOD = 1U << 8, PERF_SAMPLE_STREAM_ID = 1U << 9, - PERF_SAMPLE_TP_RECORD = 1U << 10, + PERF_SAMPLE_RAW = 1U << 10, PERF_SAMPLE_MAX = 1U << 11, /* non-ABI */ }; @@ -414,9 +414,9 @@ struct perf_callchain_entry { __u64 ip[PERF_MAX_STACK_DEPTH]; }; -struct perf_tracepoint_record { - int size; - char *record; +struct perf_raw_record { + u32 size; + void *data; }; struct task_struct; @@ -687,7 +687,7 @@ struct perf_sample_data { struct pt_regs *regs; u64 addr; u64 period; - void *private; + struct perf_raw_record *raw; }; extern int perf_counter_overflow(struct perf_counter *counter, int nmi, -- cgit v1.2.3-70-g09d2 From a044560c3a1f0ad75ce685c1ed7604820b9ed319 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 10 Aug 2009 11:16:52 +0200 Subject: perf_counter: Correct PERF_SAMPLE_RAW output PERF_SAMPLE_* output switches should unconditionally output the correct format, as they are the only way to unambiguously parse the PERF_EVENT_SAMPLE data. Signed-off-by: Peter Zijlstra Acked-by: Frederic Weisbecker Cc: Arnaldo Carvalho de Melo Cc: Mike Galbraith Cc: Paul Mackerras LKML-Reference: <1249896447.17467.74.camel@twins> Signed-off-by: Ingo Molnar --- include/linux/perf_counter.h | 2 ++ include/trace/ftrace.h | 3 ++- kernel/perf_counter.c | 30 ++++++++++++++++++++++++------ 3 files changed, 28 insertions(+), 7 deletions(-) (limited to 'include') diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h index 2aabe43c1d0..a9d823a93fe 100644 --- a/include/linux/perf_counter.h +++ b/include/linux/perf_counter.h @@ -369,6 +369,8 @@ enum perf_event_type { * * { u64 nr, * u64 ips[nr]; } && PERF_SAMPLE_CALLCHAIN + * { u32 size; + * char data[size];}&& PERF_SAMPLE_RAW * }; */ PERF_EVENT_SAMPLE = 9, diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index 7fb16d90e7b..7167b9b97da 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -685,7 +685,8 @@ static void ftrace_profile_##call(proto) \ pc = preempt_count(); \ \ __data_size = ftrace_get_offsets_##call(&__data_offsets, args); \ - __entry_size = ALIGN(__data_size + sizeof(*entry), sizeof(u64));\ + __entry_size = ALIGN(__data_size + sizeof(*entry) + sizeof(u32),\ + sizeof(u64)); \ \ do { \ char raw_data[__entry_size]; \ diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index 546e62d6294..5229d1666fa 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -2646,7 +2646,6 @@ static void perf_counter_output(struct perf_counter *counter, int nmi, u64 counter; } group_entry; struct perf_callchain_entry *callchain = NULL; - struct perf_raw_record *raw = NULL; int callchain_size = 0; u64 time; struct { @@ -2716,9 +2715,15 @@ static void perf_counter_output(struct perf_counter *counter, int nmi, } if (sample_type & PERF_SAMPLE_RAW) { - raw = data->raw; - if (raw) - header.size += raw->size; + int size = sizeof(u32); + + if (data->raw) + size += data->raw->size; + else + size += sizeof(u32); + + WARN_ON_ONCE(size & (sizeof(u64)-1)); + header.size += size; } ret = perf_output_begin(&handle, counter, header.size, nmi, 1); @@ -2784,8 +2789,21 @@ static void perf_counter_output(struct perf_counter *counter, int nmi, } } - if ((sample_type & PERF_SAMPLE_RAW) && raw) - perf_output_copy(&handle, raw->data, raw->size); + if (sample_type & PERF_SAMPLE_RAW) { + if (data->raw) { + perf_output_put(&handle, data->raw->size); + perf_output_copy(&handle, data->raw->data, data->raw->size); + } else { + struct { + u32 size; + u32 data; + } raw = { + .size = sizeof(u32), + .data = 0, + }; + perf_output_put(&handle, raw); + } + } perf_output_end(&handle); } -- cgit v1.2.3-70-g09d2 From 304703aba31a87903b8c0db8f5e6890cac2d596d Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Mon, 10 Aug 2009 16:11:32 +0200 Subject: perf_counter: Subtract the buffer size field from the event record size We compute the perf raw sample size by aligning the raw ftrace event size plus the buffer size field itself. We do that instead of aligning only the perf raw sample size, so that we might economize some in some cases. But this buffer size field is not stored in the perf raw sample, we must then substract its size from the buffer once we computed the alignment unless we may get a useless u32 field in the buffer. Signed-off-by: Frederic Weisbecker Acked-by: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Mike Galbraith Cc: Paul Mackerras LKML-Reference: <20090810141129.GA5124@nowhere> Signed-off-by: Ingo Molnar --- include/trace/ftrace.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index 7167b9b97da..a05524fa245 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -637,7 +637,12 @@ __attribute__((section("_ftrace_events"))) event_##call = { \ * pc = preempt_count(); * * __data_size = ftrace_get_offsets_(&__data_offsets, args); - * __entry_size = __data_size + sizeof(*entry); + * + * // Below we want to get the aligned size by taking into account + * // the u32 field that will later store the buffer size + * __entry_size = ALIGN(__data_size + sizeof(*entry) + sizeof(u32), + * sizeof(u64)); + * __entry_size -= sizeof(u32); * * do { * char raw_data[__entry_size]; <- allocate our sample in the stack @@ -687,6 +692,7 @@ static void ftrace_profile_##call(proto) \ __data_size = ftrace_get_offsets_##call(&__data_offsets, args); \ __entry_size = ALIGN(__data_size + sizeof(*entry) + sizeof(u32),\ sizeof(u64)); \ + __entry_size -= sizeof(u32); \ \ do { \ char raw_data[__entry_size]; \ -- cgit v1.2.3-70-g09d2 From 1853db0e02ae4088f102b0d8e59e83dc98f93f03 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Mon, 10 Aug 2009 16:38:36 +0200 Subject: perf_counter: Zero dead bytes from ftrace raw samples size alignment After aligning the ftrace raw samples, there are dead bytes storing random data from the stack. We don't want to leak these to userspace, then zero these out. Before: 0x2de88 [0x50]: event: 9 . . ... raw event: size 80 bytes . 0000: 09 00 00 00 01 00 50 00 d0 c7 00 81 ff ff ff ff ......P........ . 0010: 68 01 00 00 68 01 00 00 2c 00 00 00 00 00 00 00 h...h...,...... . 0020: 2c 00 00 00 2b 00 01 02 68 01 00 00 68 01 00 00 ,...+...h...h.. . 0030: 6b 6f 6e 64 65 6d 61 6e 64 2f 30 00 00 00 00 00 kondemand/0.... . 0040: 68 01 00 00 40 7f 46 81 ff ff ff ff 00 10 1b 7f h...@.F........ ^ ^ ^ ^ Leak After: 0x2d318 [0x50]: event: 9 . . ... raw event: size 80 bytes . 0000: 09 00 00 00 01 00 50 00 d0 c7 00 81 ff ff ff ff ......P........ . 0010: 68 01 00 00 68 01 00 00 68 14 00 00 00 00 00 00 h...h...h...... . 0020: 2c 00 00 00 2b 00 01 02 68 01 00 00 68 01 00 00 ,...+...h...h.. . 0030: 6b 6f 6e 64 65 6d 61 6e 64 2f 30 00 00 00 00 00 kondemand/0.... . 0040: 68 01 00 00 a0 80 46 81 ff ff ff ff 00 00 00 00 h.....F........ ^ ^ ^ ^ Fixed Reported-by: Peter Zijlstra Signed-off-by: Frederic Weisbecker Cc: Frederic Weisbecker Cc: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Mike Galbraith LKML-Reference: <1249915116-5210-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar Cc: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Mike Galbraith --- include/trace/ftrace.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include') diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index a05524fa245..f64fbaae781 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -648,6 +648,9 @@ __attribute__((section("_ftrace_events"))) event_##call = { \ * char raw_data[__entry_size]; <- allocate our sample in the stack * struct trace_entry *ent; * + * zero dead bytes from alignment to avoid stack leak to userspace: + * + * *(u64 *)(&raw_data[__entry_size - sizeof(u64)]) = 0ULL; * entry = (struct ftrace_raw_ *)raw_data; * ent = &entry->ent; * tracing_generic_entry_update(ent, irq_flags, pc); @@ -698,6 +701,7 @@ static void ftrace_profile_##call(proto) \ char raw_data[__entry_size]; \ struct trace_entry *ent; \ \ + *(u64 *)(&raw_data[__entry_size - sizeof(u64)]) = 0ULL; \ entry = (struct ftrace_raw_##call *)raw_data; \ ent = &entry->ent; \ tracing_generic_entry_update(ent, irq_flags, pc); \ -- cgit v1.2.3-70-g09d2