kernel/linux.git/tools/perf/util/sort.c, branch v3.0.34

perf tools: Incorrect use of snprintf results in SEGV

2012-03-23T18:20:51+00:00

commit b832796caa1fda8516464a003c8c7cc547bc20c2 upstream. I have a workload where perf top scribbles over the stack and we SEGV. What makes it interesting is that an snprintf is causing this. The workload is a c++ gem that has method names over 3000 characters long, but snprintf is designed to avoid overrunning buffers. So what went wrong? The problem is we assume snprintf returns the number of characters written: ret += repsep_snprintf(bf + ret, size - ret, "[%c] ", self->level); ... ret += repsep_snprintf(bf + ret, size - ret, "%s", self->ms.sym->name); Unfortunately this is not how snprintf works. snprintf returns the number of characters that would have been written if there was enough space. In the above case, if the first snprintf returns a value larger than size, we pass a negative size into the second snprintf and happily scribble over the stack. If you have 3000 character c++ methods thats a lot of stack to trample. This patch fixes repsep_snprintf by clamping the value at size - 1 which is the maximum snprintf can write before adding the NULL terminator. I get the sinking feeling that there are a lot of other uses of snprintf that have this same bug, we should audit them all. Cc: David Ahern Cc: Eric B Munson Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Yanmin Zhang Link: http://lkml.kernel.org/r/20120307114249.44275ca3@kryten Signed-off-by: Anton Blanchard Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Greg Kroah-Hartman

perf hist: Better displaying of unresolved DSOs and symbols

2010-12-06T17:12:34+00:00

In the event that a DSO has not been identified, just print out [unknown] instead of the instruction pointer as we previously were doing, which is pretty meaningless for a shared object (at least to the users perspective). The IP we print out is fairly meaningless in general anyway - it's just one (the first) of the many addresses that were lumped together as unidentified, and could span many shared objects and symbols. In reality if we see this [unknown] output then the report -D output is going to be more useful anyway as we can see all the different address that it represents. If we are printing the symbols we are still going to see this IP in that column anyway since they shouldn't resolve either. This patch also changes the symbol address printouts so that they print out 0x before the address, are left aligned, and changes the %L format string (which relies on a glibc bug) to %ll. Before: 74.11% :3259 4a6c [k] 4a6c After: 74.11% :3259 [unknown] [k] 0x4a6c Cc: Frederic Weisbecker Cc: Mike Galbraith Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Stephane Eranian LKML-Reference: <1291603026-11785-2-git-send-email-imunsie@au1.ibm.com> Signed-off-by: Ian Munsie Signed-off-by: Arnaldo Carvalho de Melo

perf hists: Fixup addr snprintf width on 32 bit arches

2010-08-05T22:38:01+00:00

By using BITS_PER_LONG/4 as the width specifier. Cc: Frederic Weisbecker Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Stephane Eranian LKML-Reference: Signed-off-by: Arnaldo Carvalho de Melo

perf sort: Make column width code per hists instance

2010-07-23T11:55:59+00:00

They were globals, and since we support multiple hists and sessions at the same time, it doesn't make sense to calculate those values considereing all symbols in all sessions. Cc: Frederic Weisbecker Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Stephane Eranian LKML-Reference: Signed-off-by: Arnaldo Carvalho de Melo

perf report: Implement --sort cpu

2010-06-05T12:35:53+00:00

In a shared multi-core environment, users want to analyze why their program was slow. In particular, if the code ran slower only on certain CPUs due to interference from other programs or kernel threads, the user should be able to notice that. Sample usage: perf record -f -a -- sleep 3 perf report --sort cpu,comm Workload: program is running on 16 CPUs Experiencing interference from an antagonist only on 4 CPUs. Samples: 106218177676 cycles Overhead CPU Command ........ ... ............... 6.25% 2 program 6.24% 6 program 6.24% 11 program 6.24% 5 program 6.24% 9 program 6.24% 10 program 6.23% 15 program 6.23% 7 program 6.23% 3 program 6.23% 14 program 6.22% 1 program 6.20% 13 program 3.17% 12 program 3.15% 8 program 3.14% 0 program 3.13% 4 program 3.11% 4 antagonist 3.11% 0 antagonist 3.10% 8 antagonist 3.07% 12 antagonist Cc: David S. Miller Cc: Frédéric Weisbecker Cc: Ingo Molnar Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Tom Zanussi LKML-Reference: <20100505181612.GA5091@sharma-home.net> Signed-off-by: Arun Sharma Signed-off-by: Arnaldo Carvalho de Melo

perf options: Type check all the remaining OPT_ variants

2010-05-17T19:22:41+00:00

OPT_SET_INT was renamed to OPT_SET_UINT since the only use in these tools is to set something that has an enum type, that is builtin compatible with unsigned int. Several string constifications were done to make OPT_STRING require a const char * type. Cc: Frédéric Weisbecker Cc: Mike Galbraith Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Tom Zanussi LKML-Reference: Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Fix accidentally preprocessed snprintf callback

2010-04-14T19:59:21+00:00

struct sort_entry has a callback named snprintf that turns an entry into a string result. But there are glibc versions that implement snprintf through a macro. The following expression is then going to get the snprintf call preprocessed: ent->snprintf(...) to finally end up in a build error: util/hist.c: Dans la fonction «hist_entry__snprintf» : util/hist.c:539: erreur: «struct sort_entry» has no member named «__builtin___snprintf_chk» To fix this, prepend struct sort_entry callbacks with an "se_" prefix. Signed-off-by: Frederic Weisbecker Cc: Peter Zijlstra Cc: Paul Mackerras Cc: Ingo Molnar Signed-off-by: Arnaldo Carvalho de Melo

perf tools: sort_dimension__add shouldn't die

2010-04-02T19:28:35+00:00

Propagate error instead. LKML-Reference: Cc: Frédéric Weisbecker Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Paul Mackerras Signed-off-by: Arnaldo Carvalho de Melo

perf hist: Replace ->print() routines by ->snprintf() equivalents

2010-04-02T19:28:15+00:00

Then hist_entry__fprintf will just us the newly introduced hist_entry__snprintf, add the newline and fprintf it to the supplied FILE descriptor. This allows us to remove the use_browser checking in the color_printf routines, that now got color_snprintf variants too. The newt TUI browser (and other GUIs that may come in the future) don't have to worry about stdio specific stuff in the strings they get from the se->snprintf routines and instead use whatever means to do the equivalent. Also the newt TUI browser don't have to use the fmemopen() hack, instead it can use the se->snprintf routines directly. For now tho use the hist_entry__snprintf routine to reduce the patch size. Cc: Frédéric Weisbecker Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Paul Mackerras Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Introduce struct map_symbol

2010-03-26T07:52:57+00:00

That will be in both struct hist_entry and struct callchain_list, so that the TUI can store a pointer to the pair (map, symbol) in the trees where hist_entries and callchain_lists are present, to allow precise annotation instead of looking for the first symbol with the selected name. Signed-off-by: Arnaldo Carvalho de Melo Cc: Frédéric Weisbecker Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Paul Mackerras LKML-Reference: <1269459619-982-4-git-send-email-acme@infradead.org> Signed-off-by: Ingo Molnar