kernel/linux.git/tools, branch v3.0.28

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 tools: Fix perf stack to non executable on x86_64

2012-02-20T20:48:09+00:00

commit 7a0153ee15575a4d07b5da8c96b79e0b0fd41a12 upstream. By adding following objects: bench/mem-memcpy-x86-64-asm.o the x86_64 perf binary ended up with executable stack. The reason was that above object are assembler sourced and is missing the GNU-stack note section. In such case the linker assumes that the final binary should not be restricted at all and mark the stack as RWX. Adding section ".note.GNU-stack" definition to mentioned object, with all flags disabled, thus omiting this object from linker stack flags decision. Problem introduced in: $ git describe ea7872b v2.6.37-rc2-19-gea7872b Reported-at: https://bugzilla.redhat.com/show_bug.cgi?id=783570 Reported-by: Clark Williams Acked-by: Eric Dumazet Cc: Corey Ashford Cc: Ingo Molnar Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1328100848-5630-1-git-send-email-jolsa@redhat.com Signed-off-by: Jiri Olsa [ committer note: Backported fix to perf/urgent (3.3-rc2+) ] Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Greg Kroah-Hartman

perf evsel: Fix an issue where perf report fails to show the proper percentage

2012-02-20T20:48:08+00:00

commit a4a03fc7ef89020baca4f19174e6a43767c6d78a upstream. This patch fixes an issue where perf report shows nan% for certain perf.data files. The below is from a report for a do_fork probe: -nan% sshd [kernel.kallsyms] [k] do_fork -nan% packagekitd [kernel.kallsyms] [k] do_fork -nan% dbus-daemon [kernel.kallsyms] [k] do_fork -nan% bash [kernel.kallsyms] [k] do_fork A git bisect shows commit f3bda2c as the cause. However, looking back through the git history, I saw commit 640c03c which seems to have removed the required initialization for perf_sample->period. The problem only started showing after commit f3bda2c. The below patch re-introduces the initialization and it fixes the problem for me. With the below patch, for the same perf.data: 73.08% bash [kernel.kallsyms] [k] do_fork 8.97% 11-dhclient [kernel.kallsyms] [k] do_fork 6.41% sshd [kernel.kallsyms] [k] do_fork 3.85% 20-chrony [kernel.kallsyms] [k] do_fork 2.56% sendmail [kernel.kallsyms] [k] do_fork This patch applies over current linux-tip commit 9949284. Problem introduced in: $ git describe 640c03c v2.6.37-rc3-83-g640c03c Cc: Ananth N Mavinakayanahalli Cc: Ingo Molnar Cc: Robert Richter Cc: Srikar Dronamraju Link: http://lkml.kernel.org/r/20120203170113.5190.25558.stgit@localhost6.localdomain6 Signed-off-by: Naveen N. Rao Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Greg Kroah-Hartman

perf: Fix parsing of __print_flags() in TP_printk()

2012-01-12T19:35:05+00:00

commit 49908a1b25d448d68fd26faca260e1850201575f upstream. A update is made to the sched:sched_switch event that adds some logic to the first parameter of the __print_flags() that shows the state of tasks. This change cause perf to fail parsing the flags. A simple fix is needed to have the parser be able to process ops within the argument. Reported-by: Andrew Vagin Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman

perf: Fix parsing of __print_flags() in TP_printk()

2011-12-09T16:52:49+00:00

commit d06c27b22aa66e48e32f03f9387328a9af9b0625 upstream. A update is made to the sched:sched_switch event that adds some logic to the first parameter of the __print_flags() that shows the state of tasks. This change cause perf to fail parsing the flags. A simple fix is needed to have the parser be able to process ops within the argument. Reported-by: Andrew Vagin Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman

perf probe: Fix to show correct error string

2011-11-11T17:35:53+00:00

commit 44a56040a0037a845d5fa218dffde464579f0cab upstream. Fix perf probe to show correct error string when it fails to delete an event. The write(2) returns -1 if failed, and errno stores real error number. Signed-off-by: Masami Hiramatsu Cc: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Paul Mackerras Cc: Ingo Molnar Link: http://lkml.kernel.org/r/20111004104504.14591.41266.stgit@fedora15 Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman

perf symbols: Fix ppc64 SEGV in dso__load_sym with debuginfo files

2011-10-03T18:41:02+00:00

commit adb091846318f86e4f46c7d6a7b40d2f478abdbe upstream. 64bit PowerPC debuginfo files have an empty function descriptor section. I hit a SEGV when perf tried to use this section for symbol resolution. To fix this we need to check the section is valid and we can do this by checking for type SHT_PROGBITS. Cc: Cc: Ingo Molnar Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Eric B Munson Link: http://lkml.kernel.org/r/20110824065242.895239970@samba.org Signed-off-by: Anton Blanchard Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Greg Kroah-Hartman

perf tools: do not look at ./config for configuration

2011-08-17T17:55:54+00:00

commit aba8d056078e47350d85b06a9cabd5afcc4b72ea upstream. In addition to /etc/perfconfig and $HOME/.perfconfig, perf looks for configuration in the file ./config, imitating git which looks at $GIT_DIR/config. If ./config is not a perf configuration file, it fails, or worse, treats it as a configuration file and changes behavior in some unexpected way. "config" is not an unusual name for a file to be lying around and perf does not have a private directory dedicated for its own use, so let's just stop looking for configuration in the cwd. Callers needing context-sensitive configuration can use the PERF_CONFIG environment variable. Requested-by: Christian Ohm Cc: 632923@bugs.debian.org Cc: Ben Hutchings Cc: Christian Ohm Cc: Ingo Molnar Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20110805165838.GA7237@elie.gateway.2wire.net Signed-off-by: Jonathan Nieder Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Greg Kroah-Hartman

perf tools: Fix endian conversion reading event attr from file header

2011-08-05T04:58:35+00:00

commit eda3913bb70ecebac13adccffe1e7f96e93cee02 upstream. The perf_event_attr struct has two __u32's at the top and they need to be swapped individually. With this change I was able to analyze a perf.data collected in a 32-bit PPC VM on an x86 system. I tested both 32-bit and 64-bit binaries for the Intel analysis side; both read the PPC perf.data file correctly. -v2: - changed the existing perf_event__attr_swap() to swap only elements of perf_event_attr and exported it for use in swapping the attributes in the file header - updated swap_ops used for processing events Signed-off-by: David Ahern Acked-by: Frederic Weisbecker Cc: acme@ghostprotocols.net Cc: peterz@infradead.org Cc: paulus@samba.org Link: http://lkml.kernel.org/r/1310754849-12474-1-git-send-email-dsahern@gmail.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

perf tools, x86: Fix 32-bit compile on 64-bit system

2011-08-05T04:58:35+00:00

commit 08a4a43fc407d780bdde36d98f89c0dbb2a6be6b upstream. Builds for 32-bit perf binaries on a 64-bit host currently fail with this error: [...] bench/../../../arch/x86/lib/memcpy_64.S: Assembler messages: bench/../../../arch/x86/lib/memcpy_64.S:29: Error: bad register name `%rdi' bench/../../../arch/x86/lib/memcpy_64.S:34: Error: invalid instruction suffix for `movs' bench/../../../arch/x86/lib/memcpy_64.S:50: Error: bad register name `%rdi' bench/../../../arch/x86/lib/memcpy_64.S:61: Error: bad register name `%rdi' ... The problem is the detection of the host arch without considering passed in flags. This change fixes 32-bit builds via: make EXTRA_CFLAGS=-m32 and 64-bit builds still reference the memcpy_64.S. Signed-off-by: David Ahern Acked-by: Frederic Weisbecker Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1310420304-21452-1-git-send-email-dsahern@gmail.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman