1. 02 Jan, 2019 1 commit
  2. 28 Dec, 2018 17 commits
  3. 21 Dec, 2018 4 commits
    • Arnaldo Carvalho de Melo's avatar
      perf trace: Do not hardcode the size of the tracepoint common_ fields · b9b6a2ea
      Arnaldo Carvalho de Melo authored
      We shouldn't hardcode the size of the tracepoint common_ fields, use the
      offset of the 'id'/'__syscallnr' field in the sys_enter event instead.
      
      This caused the augmented syscalls code to fail on a particular build of a
      PREEMPT_RT_FULL kernel where these extra 'common_migrate_disable' and
      'common_padding' fields were before the syscall id one:
      
        # cat /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/format
        name: sys_enter
        ID: 22
        format:
      	field:unsigned short common_type;	offset:0;	size:2;	signed:0;
      	field:unsigned char common_flags;	offset:2;	size:1;	signed:0;
      	field:unsigned char common_preempt_count;	offset:3;	size:1;	signed:0;
      	field:int common_pid;	offset:4;	size:4;	signed:1;
      	field:unsigned short common_migrate_disable;	offset:8;	size:2;	signed:0;
      	field:unsigned short common_padding;	offset:10;	size:2;	signed:0;
      
      	field:long id;	offset:16;	size:8;	signed:1;
      	field:unsigned long args[6];	offset:24;	size:48;	signed:0;
      
        print fmt: "NR %ld (%lx, %lx, %lx, %lx, %lx, %lx)", REC->id, REC->args[0], REC->args[1], REC->args[2], REC->args[3], REC->args[4], REC->args[5]
        #
      
      All those 'common_' prefixed fields are zeroed when they hit a BPF tracepoint
      hook, we better just discard those, i.e. somehow pass an offset to the
      BPF program from the start of the ctx and make adjustments in the 'perf trace'
      handlers to adjust the offset of the syscall arg offsets obtained from tracefs.
      
      Till then, fix it the quick way and add this to the augmented_raw_syscalls.c to
      bet it to work in such kernels:
      
        diff --git a/tools/perf/examples/bpf/augmented_raw_syscalls.c b/tools/perf/examples/bpf/augmented_raw_syscalls.c
        index 53c233370fae..1f746f931e13 100644
        --- a/tools/perf/examples/bpf/augmented_raw_syscalls.c
        +++ b/tools/perf/examples/bpf/augmented_raw_syscalls.c
        @@ -38,12 +38,14 @@ struct bpf_map SEC("maps") syscalls = {
      
         struct syscall_enter_args {
                unsigned long long common_tp_fields;
        +       long               rt_common_tp_fields;
                long               syscall_nr;
                unsigned long      args[6];
         };
      
         struct syscall_exit_args {
                unsigned long long common_tp_fields;
        +       long               rt_common_tp_fields;
                long               syscall_nr;
                long               ret;
         };
      
      Just to check that this was the case. Fix it properly later, for now remove the
      hardcoding of the offset in the 'perf trace' side and document the situation
      with this patch.
      
      Cc: Adrian Hunter <adrian.hunter@intel.com>
      Cc: Jiri Olsa <jolsa@kernel.org>
      Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Wang Nan <wangnan0@huawei.com>
      Link: https://lkml.kernel.org/n/tip-2pqavrktqkliu5b9nzouio21@git.kernel.orgSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      b9b6a2ea
    • Stanislav Fomichev's avatar
      perf build: Don't unconditionally link the libbfd feature test to -liberty and -lz · 14541b1e
      Stanislav Fomichev authored
      Current libbfd feature test unconditionally links against -liberty and -lz.
      While it's required on some systems (e.g. opensuse), it's completely
      unnecessary on the others, where only -lbdf is sufficient (debian).
      This patch streamlines (and renames) the following feature checks:
      
      feature-libbfd           - only link against -lbfd (debian),
                                 see commit 2cf90407 ("perf tools: Fix bfd
      			   dependency libraries detection")
      feature-libbfd-liberty   - link against -lbfd and -liberty
      feature-libbfd-liberty-z - link against -lbfd, -liberty and -lz (opensuse),
                                 see commit 280e7c48 ("perf tools: fix BFD
      			   detection on opensuse")
      
      (feature-liberty{,-z} were renamed to feature-libbfd-liberty{,z}
      for clarity)
      
      The main motivation is to fix this feature test for bpftool which is
      currently broken on debian (libbfd feature shows OFF, but we still
      unconditionally link against -lbfd and it works).
      
      Tested on debian with only -lbfd installed (without -liberty); I'd
      appreciate if somebody on the other systems can test this new detection
      method.
      Signed-off-by: default avatarStanislav Fomichev <sdf@google.com>
      Acked-by: default avatarJiri Olsa <jolsa@kernel.org>
      Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
      Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Link: http://lkml.kernel.org/r/4dfc634cfcfb236883971b5107cf3c28ec8a31be.1542328222.git.sdf@google.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      14541b1e
    • Arnaldo Carvalho de Melo's avatar
      perf beauty mmap: PROT_WRITE should come before PROT_EXEC · 5ce29d52
      Arnaldo Carvalho de Melo authored
      To match strace output:
      
        # cat mmap.c
        #include <sys/mman.h>
      
        int main(void)
        {
      	  mmap(0, 4096, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
      	  return 0;
        }
        # strace -e mmap ./mmap |& grep -v ^+++
        mmap(NULL, 103484, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f5bae400000
        mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f5bae3fe000
        mmap(NULL, 3889792, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f5bade40000
        mmap(0x7f5bae1ec000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1ac000) = 0x7f5bae1ec000
        mmap(0x7f5bae1f2000, 14976, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f5bae1f2000
        mmap(NULL, 4096, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f5bae419000
        # trace -e mmap ./mmap |& grep -v ^+++
        mmap(NULL, 103484, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f6646c25000
        mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS) = 0x7f6646c23000
        mmap(NULL, 3889792, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f6646665000
        mmap(0x7f6646a11000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1ac000) = 0x7f6646a11000
        mmap(0x7f6646a17000, 14976, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS) = 0x7f6646a17000
        mmap(NULL, 4096, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANONYMOUS) = 0x7f6646c3e000
        #
      Reported-by: default avatarNamhyung Kim <namhyung@kernel.org>
      Cc: Adrian Hunter <adrian.hunter@intel.com>
      Cc: Jiri Olsa <jolsa@kernel.org>
      Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
      Cc: Wang Nan <wangnan0@huawei.com>
      Link: https://lkml.kernel.org/n/tip-nt49d6iqle80cw8f529ovaqi@git.kernel.orgSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      5ce29d52
    • Arnaldo Carvalho de Melo's avatar
      perf trace: Check if the raw_syscalls:sys_{enter,exit} are setup before setting tp filter · f76214f9
      Arnaldo Carvalho de Melo authored
      While updating 'perf trace' on an machine with an old precompiled
      augmented_raw_syscalls.o that didn't setup the syscall map the new 'perf
      trace' codebase notices the augmented_raw_syscalls.o eBPF event, decides
      to use it instead of the old raw_syscalls:sys_{enter,exit} method, but
      then because we don't have the syscall map tries to set the tracepoint
      filter on the sys_{enter,exit} evsels, that are NULL, segfaulting.
      
      Make the code more robust by checking it those tracepoints have
      their respective evsels in place before trying to set the tp filter.
      
      With this we still get everything to work, just not setting up the
      syscall filters, which is better than a segfault. Now to update the
      precompiled augmented_raw_syscalls.o and continue development :-)
      
      Cc: Adrian Hunter <adrian.hunter@intel.com>
      Cc: Jiri Olsa <jolsa@kernel.org>
      Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Wang Nan <wangnan0@huawei.com>
      Link: https://lkml.kernel.org/n/tip-3ft5rjdl05wgz2pwpx2z8btu@git.kernel.orgSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      f76214f9
  4. 18 Dec, 2018 18 commits