Commit Graph

23 Commits

Author SHA1 Message Date
Arnaldo Carvalho de Melo
602bce09fb perf augmented_raw_syscalls: Move reading filename to the loop
Almost there, next step is to copy more than one filename payload.

Probably to read syscall arg structs, etc we'll need just a variation of
this that will decide what to use, if probe_read_str() or plain
probe_read for structs, i.e. fixed size.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-uf6u0pld6xe4xuo16f04owlz@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-06-05 09:48:55 -03:00
Arnaldo Carvalho de Melo
deaf4da48a perf augmented_raw_syscalls: Change helper to consider just the augmented_filename part
So that we can use it for multiple args, baby steps not to step into the
verifier toes.

In the process make sure we handle -EFAULT from bpf_prog_read_str(), as
this really is needed now that we'll handle more than one augmented
argument, i.e. if there is failure, then we have the argument that fails
have:

  (size = 0, err = -EFAULT, value = [] )

followed by the next, lets say that worked for a second pathname:

  (size = 4, err = 0, value = "/tmp" )

So we can skip the first while telling the user about the problem and
then process the second.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-deyvqi39um6gp6hux6jovos8@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-06-05 09:48:54 -03:00
Arnaldo Carvalho de Melo
0c95a7ff76 perf augmented_raw_syscalls: Move the probe_read_str to a separate function
One more step into copying multiple filenames to support syscalls like
rename*.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-xdqtjexdyp81oomm1rkzeifl@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-06-05 09:47:58 -03:00
Arnaldo Carvalho de Melo
4cae8675ea perf augmented_raw_syscalls: Tell which args are filenames and how many bytes to copy
Since we know what args are strings from reading the syscall
descriptions in tracefs and also already mark such args to be beautified
using the syscall_arg__scnprintf_filename() helper, all we need is to
fill in this info in the 'syscalls' BPF map we were using to state which
syscalls the user is interested in, i.e. the syscall filter.

Right now just set that with PATH_MAX and unroll the syscall arg in the
BPF program, as the verifier isn't liking something clang generates when
unrolling the loop.

This also makes the augmented_raw_syscalls.c program support all arches,
since we removed that set of defines with the hard coded syscall
numbers, all should be automatically set for all arches, with the
syscall id mapping done correcly.

Doing baby steps here, i.e. just the first string arg for a syscall is
printed, syscalls with more than one, say, the various rename* syscalls,
need further work, but lets get first something that the BPF verifier
accepts before increasing the complexity

To test it, something like:

 # perf trace -e string -e /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c

With:

  # cat ~/.perfconfig
  [llvm]
	dump-obj = true
	clang-opt = -g
  [trace]
	#add_events = /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c
	show_zeros = yes
	show_duration = no
	no_inherit = yes
	show_timestamp = no
	show_arg_names = no
	args_alignment = 40
	show_prefix = yes
  #

That commented add_events line is needed for developing this
augmented_raw_syscalls.c BPF program, as if we add it via the
'add_events' mechanism so as to shorten the 'perf trace' command lines,
then we end up not setting up the -v option which precludes us having
access to the bpf verifier log :-\

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Link: https://lkml.kernel.org/n/tip-dn863ya0cbsqycxuy0olvbt1@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-06-05 09:47:58 -03:00
Arnaldo Carvalho de Melo
693bd3949b perf trace: Beautify 'fspick' arguments
Use existing beautifiers for the first 2 args (dfd, path) and wire up
the recently introduced fspick flags table generator.

Now it should be possible to just use:

   perf trace -e fspick

As root and see all move_mount syscalls with its args beautified, either
using the vfs_getname perf probe method or using the
augmented_raw_syscalls.c eBPF helper to get the pathnames, the other
args should work in all cases, i.e. all that is needed can be obtained
directly from the raw_syscalls:sys_enter tracepoint args.

  # cat sys_fspick.c
  #define _GNU_SOURCE        /* See feature_test_macros(7) */
  #include <unistd.h>
  #include <sys/syscall.h>   /* For SYS_xxx definitions */
  #include <fcntl.h>

  #define __NR_fspick 433

  #define FSPICK_CLOEXEC          0x00000001
  #define FSPICK_SYMLINK_NOFOLLOW 0x00000002
  #define FSPICK_NO_AUTOMOUNT     0x00000004
  #define FSPICK_EMPTY_PATH       0x00000008

  static inline int sys_fspick(int fd, const char *path, int flags)
  {
  	syscall(__NR_fspick, fd, path, flags);
  }

  int main(int argc, char *argv[])
  {
  	int flags = 0, fd = 0;

  	open("/foo", 0);
  	sys_fspick(fd++, "/foo1", flags);
  	flags |= FSPICK_CLOEXEC;
  	sys_fspick(fd++, "/foo2", flags);
  	flags |= FSPICK_SYMLINK_NOFOLLOW;
  	sys_fspick(fd++, "/foo3", flags);
  	flags |= FSPICK_NO_AUTOMOUNT;
  	sys_fspick(fd++, "/foo4", flags);
  	flags |= FSPICK_EMPTY_PATH;
  	return sys_fspick(fd++, "/foo5", flags);
  }
  # perf trace -e fspick ./sys_fspick
  LLVM: dumping /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o
  fspick(0, "/foo1", 0)                   = -1 ENOENT (No such file or directory)
  fspick(1, "/foo2", FSPICK_CLOEXEC)      = -1 ENOENT (No such file or directory)
  fspick(2, "/foo3", FSPICK_CLOEXEC|FSPICK_SYMLINK_NOFOLLOW) = -1 ENOENT (No such file or directory)
  fspick(3, "/foo4", FSPICK_CLOEXEC|FSPICK_SYMLINK_NOFOLLOW|FSPICK_NO_AUTOMOUNT) = -1 ENOENT (No such file or directory)
  fspick(4, "/foo5", FSPICK_CLOEXEC|FSPICK_SYMLINK_NOFOLLOW|FSPICK_NO_AUTOMOUNT|FSPICK_EMPTY_PATH) = -1 ENOENT (No such file or directory)
  #

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-erau5xjtt8wvgnhvdbchstuk@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-05-28 18:37:42 -03:00
Arnaldo Carvalho de Melo
566e30229e perf trace: Beautify 'move_mount' arguments
Use existing beautifiers for the first 4 args (to/from fds, pathnames)
and wire up the recently introduced move_mount flags table generator.

Now it should be possible to just use:

      perf trace -e move_mount

As root and see all move_mount syscalls with its args beautified, except
for the filenames, that need work in the augmented_raw_syscalls.c eBPF
helper to pass more than one, see comment in the
augmented_raw_syscalls.c source code, the other args should work in all
cases, i.e. all that is needed can be obtained directly from the
raw_syscalls:sys_enter tracepoint args.

Running without the strace "skin" (.perfconfig setting output formatting
switches to look like strace output + BPF to collect strings, as we
still need to support collecting multiple string args for the same
syscall, like with move_mount):

  # cat sys_move_mount.c
  #define _GNU_SOURCE         /* See feature_test_macros(7) */
  #include <unistd.h>
  #include <sys/syscall.h>   /* For SYS_xxx definitions */

  #define __NR_move_mount 429

  #define MOVE_MOUNT_F_SYMLINKS		0x00000001 /* Follow symlinks on from path */
  #define MOVE_MOUNT_F_AUTOMOUNTS		0x00000002 /* Follow automounts on from path */
  #define MOVE_MOUNT_F_EMPTY_PATH		0x00000004 /* Empty from path permitted */
  #define MOVE_MOUNT_T_SYMLINKS		0x00000010 /* Follow symlinks on to path */
  #define MOVE_MOUNT_T_AUTOMOUNTS		0x00000020 /* Follow automounts on to path */
  #define MOVE_MOUNT_T_EMPTY_PATH		0x00000040 /* Empty to path permitted */

  static inline int sys_move_mount(int from_fd, const char *from_pathname,
  				 int to_fd, const char *to_pathname,
  				 int flags)
  {
  	  syscall(__NR_move_mount, from_fd, from_pathname, to_fd, to_pathname, flags);
  }

  int main(int argc, char *argv[])
  {
  	  int flags = 0, from_fd = 0, to_fd = 100;

  	  sys_move_mount(from_fd++, "/foo", to_fd++, "bar", flags);
  	  flags |= MOVE_MOUNT_F_SYMLINKS;
  	  sys_move_mount(from_fd++, "/foo1", to_fd++, "bar1", flags);
          flags |= MOVE_MOUNT_F_AUTOMOUNTS;
  	  sys_move_mount(from_fd++, "/foo2", to_fd++, "bar2", flags);
          flags |= MOVE_MOUNT_F_EMPTY_PATH;
  	  sys_move_mount(from_fd++, "/foo3", to_fd++, "bar3", flags);
          flags |= MOVE_MOUNT_T_SYMLINKS;
  	  sys_move_mount(from_fd++, "/foo4", to_fd++, "bar4", flags);
          flags |= MOVE_MOUNT_T_AUTOMOUNTS;
  	  sys_move_mount(from_fd++, "/foo5", to_fd++, "bar5", flags);
          flags |= MOVE_MOUNT_T_EMPTY_PATH;
  	  return sys_move_mount(from_fd++, "/foo6", to_fd++, "bar6", flags);
  }
  # mv ~/.perfconfig  ~/.perfconfig.OFF
  # perf trace -e move_mount ./sys_move_mount
       0.000 ( 0.009 ms): sys_move_mount/28971 move_mount(from_pathname: 0x402010, to_dfd: 100, to_pathname: 0x402015) = -1 ENOENT (No such file or directory)
       0.011 ( 0.003 ms): sys_move_mount/28971 move_mount(from_dfd: 1, from_pathname: 0x40201e, to_dfd: 101, to_pathname: 0x402019, flags: F_SYMLINKS) = -1 ENOENT (No such file or directory)
       0.016 ( 0.002 ms): sys_move_mount/28971 move_mount(from_dfd: 2, from_pathname: 0x402029, to_dfd: 102, to_pathname: 0x402024, flags: F_SYMLINKS|F_AUTOMOUNTS) = -1 ENOENT (No such file or directory)
       0.020 ( 0.002 ms): sys_move_mount/28971 move_mount(from_dfd: 3, from_pathname: 0x402034, to_dfd: 103, to_pathname: 0x40202f, flags: F_SYMLINKS|F_AUTOMOUNTS|F_EMPTY_PATH) = -1 ENOENT (No such file or directory)
       0.023 ( 0.002 ms): sys_move_mount/28971 move_mount(from_dfd: 4, from_pathname: 0x40203f, to_dfd: 104, to_pathname: 0x40203a, flags: F_SYMLINKS|F_AUTOMOUNTS|F_EMPTY_PATH|T_SYMLINKS) = -1 ENOENT (No such file or directory)
       0.027 ( 0.002 ms): sys_move_mount/28971 move_mount(from_dfd: 5, from_pathname: 0x40204a, to_dfd: 105, to_pathname: 0x402045, flags: F_SYMLINKS|F_AUTOMOUNTS|F_EMPTY_PATH|T_SYMLINKS|T_AUTOMOUNTS) = -1 ENOENT (No such file or directory)
       0.031 ( 0.017 ms): sys_move_mount/28971 move_mount(from_dfd: 6, from_pathname: 0x402055, to_dfd: 106, to_pathname: 0x402050, flags: F_SYMLINKS|F_AUTOMOUNTS|F_EMPTY_PATH|T_SYMLINKS|T_AUTOMOUNTS|T_EMPTY_PATH) = -1 ENOENT (No such file or directory)
  #

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-83rim8g4k0s4gieieh5nnlck@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-05-28 18:37:42 -03:00
Arnaldo Carvalho de Melo
8a70c6b162 perf augmented_raw_syscalls: Fix up comment
Cut'n'paste error, the second comment is about the syscalls that have as
its second arg a string.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-zo5s6rloy42u41acsf6q3pvi@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-05-28 18:37:42 -03:00
Arnaldo Carvalho de Melo
59f3bd7802 perf augmented_raw_syscalls: Use a PERCPU_ARRAY map to copy more string bytes
The previous method, copying to the BPF stack limited us in how many
bytes we could copy from strings, use a PERCPU_ARRAY map like devised by
the sysdig guys[1] to copy more bytes:

Before:

  # trace --no-inherit -e openat touch `python -c "print "$s" 'a' * 2000"`
  touch: cannot touch 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa': File name too long
  openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
  openat(AT_FDCWD, "/lib64/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
  openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
  openat(AT_FDCWD, "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", O_CREAT|O_NOCTTY|O_NONBLOCK|O_WRONLY, S_IRUGO|S_IWUGO) = -1 ENAMETOOLONG (File name too long)
  openat(AT_FDCWD, "/usr/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = 3
  openat(AT_FDCWD, "/usr/share/locale/en_US.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
  openat(AT_FDCWD, "/usr/share/locale/en_US.utf8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
  <SNIP some openat calls>
  #

After:

  [root@quaco acme]# trace --no-inherit -e openat touch `python -c "print "$s" 'a' * 2000"`
  <STRIP what is the same as in the 'before' part>
  openat(AT_FDCWD, "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", O_CREAT|O_NOCTTY|O_NONBLOC) = -1 ENAMETOOLONG (File name too long)
  <STRIP what is the same as in the 'before' part>

If we leave something like 'perf trace -e string' to trace all syscalls
with a string, and then do some 'perf top', to get some annotation for
the augmented_raw_syscalls.o BPF program we get:

       │     → callq  *ffffffffc45576d1                                                                                                          ▒
       │                augmented_args->filename.size = probe_read_str(&augmented_args->filename.value,                                          ▒
  0.05 │       mov    %eax,0x40(%r13)

Looking with pahole, expanding types, asking for hex offsets and sizes,
and use of BTF type information to see what is at that 0x40 offset from
%r13:

  # pahole -F btf -C augmented_args_filename --expand_types --hex /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o
  struct augmented_args_filename {
	struct syscall_enter_args {
		long long unsigned int common_tp_fields;                                 /*     0   0x8 */
		long int           syscall_nr;                                           /*   0x8   0x8 */
		long unsigned int  args[6];                                              /*  0x10  0x30 */
	} args; /*     0  0x40 */
	/* --- cacheline 1 boundary (64 bytes) --- */
	struct augmented_filename {
		unsigned int       size;                                                 /*  0x40   0x4 */
		int                reserved;                                             /*  0x44   0x4 */
		char               value[4096];                                          /*  0x48 0x1000 */
	} filename; /*  0x40 0x1008 */

	/* size: 4168, cachelines: 66, members: 2 */
	/* last cacheline: 8 bytes */
  };
  #

Then looking if PATH_MAX leaves some signature in the tests:

       │                if (augmented_args->filename.size < sizeof(augmented_args->filename.value)) {                                            ▒
       │       cmp    $0xfff,%rdi

0xfff == 4095
sizeof(augmented_args->filename.value) == PATH_MAX == 4096

[1] https://sysdig.com/blog/the-art-of-writing-ebpf-programs-a-primer/

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Daniel Borkmann <borkmann@iogearbox.net>
Cc: Gianluca Borello <g.borello@gmail.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
cc: Martin Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Yonghong Song <yhs@fb.com>
Link: https://lkml.kernel.org/n/tip-76gce2d2ghzq537ubwhjkone@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-04-01 14:49:24 -03:00
Arnaldo Carvalho de Melo
c52a82f779 perf augmented_raw_syscalls: Copy strings from all syscalls with 1st or 2nd string arg
Gets the augmented_raw_syscalls a bit more useful as-is, add a comment
stating that the intent is to have all this in a map populated by
userspace via the 'syscalls' BPF map, that right now has only a flag
stating if the syscall is filtered or not.

With it:

  # grep -B1 augmented_raw ~/.perfconfig
  [trace]
	add_events = /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o
  #
  # perf trace -e string
  weechat/6001 stat("/etc/localtime", 0x7ffe22c23d10)  = 0
  gnome-shell/1943 openat(AT_FDCWD, "/proc/self/stat", O_RDONLY) = 81
  weechat/6001 stat("/etc/localtime", 0x7ffe22c23d10)  = 0
  gmain/2475 inotify_add_watch(20<anon_inode:inotify>, "/home/acme/.config/firewall", 16789454) = -1 ENOENT (No such file or directory)
  gmain/2391 inotify_add_watch(3<anon_inode:inotify>, "", 16789454) = -1 ENOENT (No such file or directory)
  gmain/2391 inotify_add_watch(3<anon_inode:inotify>, "/var/cache/app-info/yaml", 16789454) = -1 ENOENT (No such file or directory)
  gmain/2391 inotify_add_watch(3<anon_inode:inotify>, "/var/lib/app-info/xmls", 16789454) = -1 ENOENT (No such file or directory)
  gmain/2391 inotify_add_watch(3<anon_inode:inotify>, "/var/lib/app-info/yaml", 16789454) = -1 ENOENT (No such file or directory)
  gmain/2391 inotify_add_watch(3<anon_inode:inotify>, "/usr/share/app-info/yaml", 16789454) = -1 ENOENT (No such file or directory)
  gmain/2391 inotify_add_watch(3<anon_inode:inotify>, "/usr/local/share/app-info/xmls", 16789454) = -1 ENOENT (No such file or directory)
  gmain/2391 inotify_add_watch(3<anon_inode:inotify>, "/usr/local/share/app-info/yaml", 16789454) = -1 ENOENT (No such file or directory)
  gmain/2391 inotify_add_watch(3<anon_inode:inotify>, "/home/acme/.local/share/app-info/yaml", 16789454) = -1 ENOENT (No such file or directory)
  gmain/1121 inotify_add_watch(12<anon_inode:inotify>, "/etc/NetworkManager/VPN", 16789454) = -1 ENOENT (No such file or directory)
  weechat/6001 stat("/etc/localtime", 0x7ffe22c23d10)  = 0
  gmain/2050 inotify_add_watch(8<anon_inode:inotify>, "/home/acme/~", 16789454) = -1 ENOENT (No such file or directory)
  gmain/2521 inotify_add_watch(6<anon_inode:inotify>, "/var/lib/fwupd/remotes.d/lvfs-testing", 16789454) = -1 ENOENT (No such file or directory)
  weechat/6001 stat("/etc/localtime", 0x7ffe22c23d10)  = 0
  DOM Worker/22714  ... [continued]: openat())             = 257
  FS Broker 3982/3990 openat(AT_FDCWD, "/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY) = 187
  DOMCacheThread/16652 mkdir("/home/acme/.mozilla/firefox/ina67tev.default/storage/default/https+++web.whatsapp.com/cache/morgue/192", S_IRUGO|S_IXUGO|S_IWUSR) = -1 EEXIST (File exists)
  ^C#

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-a1hxffoy8t43e0wq6bzhp23u@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-04-01 14:49:24 -03:00
Arnaldo Carvalho de Melo
56d8175a4d perf augmented_raw_syscalls: Use bpf_map()
To make the code more compact and also paving the way to have the BTF
annotation to be done transparently.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Yonghong Song <yhs@fb.com>
Link: https://lkml.kernel.org/n/tip-pjlf38sv3i1hbn5vzkr4y3ol@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-01-25 15:12:10 +01:00
Arnaldo Carvalho de Melo
5620196951 perf: Make perf_event_output() propagate the output() return
For the original mode of operation it isn't needed, since we report back
errors via PERF_RECORD_LOST records in the ring buffer, but for use in
bpf_perf_event_output() it is convenient to return the errors, basically
-ENOSPC.

Currently bpf_perf_event_output() returns an error indication, the last
thing it does, which is to push it to the ring buffer is that can fail
and if so, this failure won't be reported back to its users, fix it.

Reported-by: Jamal Hadi Salim <jhs@mojatatu.com>
Tested-by: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/r/20190118150938.GN5823@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-01-21 17:00:57 -03:00
Arnaldo Carvalho de Melo
c48ee107bb perf augmented_raw_syscalls: Copy 'access' arg as well
This will all come from userspace, but to test the changes to make 'perf
trace' output similar to strace's, do this one more now manually.

To update the precompiled augmented_raw_syscalls.o binary I just run:

  # perf record -e ~acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c sleep 1
  LLVM: dumping /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.022 MB perf.data ]
  #

Because to have augmented_raw_syscalls to be always used and a fast
startup and remove the need to have the llvm toolchain installed, I'm
using:

  # perf config | grep add_events
  trace.add_events=/home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o
  #

So when doing changes to augmented_raw_syscals.c one needs to rebuild
the .o file.

This will be done automagically later, i.e. have a 'make' behaviour of
recompiling when the .c gets changed.

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-lw3i2atyq8549fpqwmszn3qp@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-12-18 16:15:18 -03:00
Arnaldo Carvalho de Melo
4623ce405d perf augmented_raw_syscalls: Do not include stdio.h
We're not using that puts() thing, and thus we don't need to define the
__bpf_stdout__ map, reducing the setup time.

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-3452xgatncpil7v22minkwbo@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-12-18 12:24:00 -03:00
Arnaldo Carvalho de Melo
27f2992e7b perf augmented_syscalls: Switch to using a struct for the syscalls map values
We'll start adding more perf-syscall stuff, so lets do this prep step so
that the next ones are just about adding more fields.

Run it with the .c file once to cache the .o file:

  # trace --filter-pids 2834,2199 -e openat,augmented_raw_syscalls.c
  LLVM: dumping augmented_raw_syscalls.o
       0.000 ( 0.021 ms): tmux: server/4952 openat(dfd: CWD, filename: /proc/5691/cmdline                         ) = 11
     349.807 ( 0.040 ms): DNS Res~er #39/11082 openat(dfd: CWD, filename: /etc/hosts, flags: CLOEXEC                 ) = 44
    4988.759 ( 0.052 ms): gsd-color/2431 openat(dfd: CWD, filename: /etc/localtime                             ) = 18
    4988.976 ( 0.029 ms): gsd-color/2431 openat(dfd: CWD, filename: /etc/localtime                             ) = 18
  ^C[root@quaco bpf]#

From now on, we can use just the newly built .o file, skipping the
compilation step for a faster startup:

  # trace --filter-pids 2834,2199 -e openat,augmented_raw_syscalls.o
       0.000 ( 0.046 ms): DNS Res~er #39/11088 openat(dfd: CWD, filename: /etc/hosts, flags: CLOEXEC                 ) = 44
    1946.408 ( 0.190 ms): systemd/1 openat(dfd: CWD, filename: /proc/1071/cgroup, flags: CLOEXEC          ) = 20
    1946.792 ( 0.215 ms): systemd/1 openat(dfd: CWD, filename: /proc/954/cgroup, flags: CLOEXEC           ) = 20
  ^C#

Now on to do the same in the builtin-trace.c side of things.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-k8mwu04l8es29rje5loq9vg7@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-12-18 12:23:58 -03:00
Arnaldo Carvalho de Melo
b27b38ed94 perf trace: Implement syscall filtering in augmented_syscalls
Just another map, this time an BPF_MAP_TYPE_ARRAY, stating with
one bool per syscall, stating if it should be filtered or not.

So, with a pre-built augmented_raw_syscalls.o file, we use:

  # perf trace -e open*,augmented_raw_syscalls.o
     0.000 ( 0.016 ms): DNS Res~er #37/29652 openat(dfd: CWD, filename: /etc/hosts, flags: CLOEXEC                 ) = 138
   187.039 ( 0.048 ms): gsd-housekeepi/2436 openat(dfd: CWD, filename: /etc/fstab, flags: CLOEXEC                 ) = 11
   187.348 ( 0.041 ms): gsd-housekeepi/2436 openat(dfd: CWD, filename: /proc/self/mountinfo, flags: CLOEXEC       ) = 11
   188.793 ( 0.036 ms): gsd-housekeepi/2436 openat(dfd: CWD, filename: /proc/self/mountinfo, flags: CLOEXEC       ) = 11
   189.803 ( 0.029 ms): gsd-housekeepi/2436 openat(dfd: CWD, filename: /proc/self/mountinfo, flags: CLOEXEC       ) = 11
   190.774 ( 0.027 ms): gsd-housekeepi/2436 openat(dfd: CWD, filename: /proc/self/mountinfo, flags: CLOEXEC       ) = 11
   284.620 ( 0.149 ms): DataStorage/3076 openat(dfd: CWD, filename: /home/acme/.mozilla/firefox/ina67tev.default/SiteSecurityServiceState.txt, flags: CREAT|TRUNC|WRONLY, mode: IRUGO|IWUSR|IWGRP) = 167
  ^C#

What is it that this gsd-housekeeping thingy needs to open
/proc/self/mountinfo four times periodically? :-)

This map will be extended to tell per-syscall parameters, i.e. how many
bytes to copy per arg, using the function signature to get the types and
then the size of those types, via BTF.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-cy222g9ucvnym3raqvxp0hpg@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-12-18 12:23:58 -03:00
Arnaldo Carvalho de Melo
4aa792de0b Revert "perf augmented_syscalls: Drop 'write', 'poll' for testing without self pid filter"
Now that we have the "filtered_pids" logic in place, no need to do this
rough filter to avoid the feedback loop from 'perf trace's own syscalls,
revert it.

This reverts commit 7ed71f124284359676b6496ae7db724fee9da753.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-88vh02cnkam0vv5f9vp02o3h@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-11-21 12:00:31 -03:00
Arnaldo Carvalho de Melo
e312747b49 perf augmented_syscalls: Remove example hardcoded set of filtered pids
Now that 'perf trace' fills in that "filtered_pids" BPF map, remove the
set of filtered pids used as an example to test that feature.

That feature works like this:

Starting a system wide 'strace' like 'perf trace' augmented session we
noticed that lots of events take place for a pid, which ends up being
the feedback loop of perf trace's syscalls being processed by the
'gnome-terminal' process:

  # perf trace -e tools/perf/examples/bpf/augmented_raw_syscalls.c
     0.391 ( 0.002 ms): gnome-terminal/2469 read(fd: 17</dev/ptmx>, buf: 0x564b79f750bc, count: 8176) = 453
     0.394 ( 0.001 ms): gnome-terminal/2469 read(fd: 17</dev/ptmx>, buf: 0x564b79f75280, count: 7724) = -1 EAGAIN Resource temporarily unavailable
     0.438 ( 0.001 ms): gnome-terminal/2469 read(fd: 4<anon_inode:[eventfd]>, buf: 0x7fffc696aeb0, count: 16) = 8
     0.519 ( 0.001 ms): gnome-terminal/2469 read(fd: 17</dev/ptmx>, buf: 0x564b79f75280, count: 7724) = 114
     0.522 ( 0.001 ms): gnome-terminal/2469 read(fd: 17</dev/ptmx>, buf: 0x564b79f752f1, count: 7611) = -1 EAGAIN Resource temporarily unavailable
  ^C

So we can use --filter-pids to get rid of that one, and in this case what is
being used to implement that functionality is that "filtered_pids" BPF map that
the tools/perf/examples/bpf/augmented_raw_syscalls.c created and that 'perf trace'
bpf loader noticed and created a "struct bpf_map" associated that then got populated
by 'perf trace':

  # perf trace --filter-pids 2469 -e tools/perf/examples/bpf/augmented_raw_syscalls.c
     0.020 ( 0.002 ms): gnome-shell/1663 epoll_pwait(epfd: 12<anon_inode:[eventpoll]>, events: 0x7ffd8f3ef960, maxevents: 32, sigsetsize: 8) = 1
     0.025 ( 0.002 ms): gnome-shell/1663 read(fd: 24</dev/input/event4>, buf: 0x560c01bb8240, count: 8112) = 48
     0.029 ( 0.001 ms): gnome-shell/1663 read(fd: 24</dev/input/event4>, buf: 0x560c01bb8258, count: 8088) = -1 EAGAIN Resource temporarily unavailable
     0.032 ( 0.001 ms): gnome-shell/1663 read(fd: 24</dev/input/event4>, buf: 0x560c01bb8240, count: 8112) = -1 EAGAIN Resource temporarily unavailable
     0.040 ( 0.003 ms): gnome-shell/1663 recvmsg(fd: 46<socket:[35893]>, msg: 0x7ffd8f3ef950) = -1 EAGAIN Resource temporarily unavailable
    21.529 ( 0.002 ms): gnome-shell/1663 epoll_pwait(epfd: 5<anon_inode:[eventpoll]>, events: 0x7ffd8f3ef960, maxevents: 32, sigsetsize: 8) = 1
    21.533 ( 0.004 ms): gnome-shell/1663 recvmsg(fd: 82<socket:[42826]>, msg: 0x7ffd8f3ef7b0, flags: DONTWAIT|CMSG_CLOEXEC) = 236
    21.581 ( 0.006 ms): gnome-shell/1663 ioctl(fd: 8</dev/dri/card0>, cmd: DRM_I915_GEM_BUSY, arg: 0x7ffd8f3ef060) = 0
    21.605 ( 0.020 ms): gnome-shell/1663 ioctl(fd: 8</dev/dri/card0>, cmd: DRM_I915_GEM_CREATE, arg: 0x7ffd8f3eeea0) = 0
    21.626 ( 0.119 ms): gnome-shell/1663 ioctl(fd: 8</dev/dri/card0>, cmd: DRM_I915_GEM_SET_DOMAIN, arg: 0x7ffd8f3eee94) = 0
    21.746 ( 0.081 ms): gnome-shell/1663 ioctl(fd: 8</dev/dri/card0>, cmd: DRM_I915_GEM_PWRITE, arg: 0x7ffd8f3eeea0) = 0
  ^C

Oops, yet another gnome process that is involved with the output that
'perf trace' generates, lets filter that out too:

  # perf trace --filter-pids 2469,1663 -e tools/perf/examples/bpf/augmented_raw_syscalls.c
         ? (         ): wpa_supplicant/1366  ... [continued]: select()) = 0 Timeout
     0.006 ( 0.002 ms): wpa_supplicant/1366 clock_gettime(which_clock: BOOTTIME, tp: 0x7fffe5b1e430) = 0
     0.011 ( 0.001 ms): wpa_supplicant/1366 clock_gettime(which_clock: BOOTTIME, tp: 0x7fffe5b1e3e0) = 0
     0.014 ( 0.001 ms): wpa_supplicant/1366 clock_gettime(which_clock: BOOTTIME, tp: 0x7fffe5b1e430) = 0
         ? (         ): gmain/1791  ... [continued]: poll()) = 0 Timeout
     0.017 (         ): wpa_supplicant/1366 select(n: 6, inp: 0x55646fed3ad0, outp: 0x55646fed3b60, exp: 0x55646fed3bf0, tvp: 0x7fffe5b1e4a0) ...
   157.879 ( 0.019 ms): gmain/1791 inotify_add_watch(fd: 8<anon_inode:inotify>, pathname: , mask: 16789454) = -1 ENOENT No such file or directory
         ? (         ): cupsd/1001  ... [continued]: epoll_pwait()) = 0
         ? (         ): gsd-color/1908  ... [continued]: poll()) = 0 Timeout
   499.615 (         ): cupsd/1001 epoll_pwait(epfd: 4<anon_inode:[eventpoll]>, events: 0x557a21166500, maxevents: 4096, timeout: 1000, sigsetsize: 8) ...
   586.593 ( 0.004 ms): gsd-color/1908 recvmsg(fd: 3<socket:[38074]>, msg: 0x7ffdef34e800) = -1 EAGAIN Resource temporarily unavailable
         ? (         ): fwupd/2230  ... [continued]: poll()) = 0 Timeout
         ? (         ): rtkit-daemon/906  ... [continued]: poll()) = 0 Timeout
         ? (         ): rtkit-daemon/907  ... [continued]: poll()) = 1
   724.603 ( 0.007 ms): rtkit-daemon/907 read(fd: 6<anon_inode:[eventfd]>, buf: 0x7f05ff768d08, count: 8) = 8
         ? (         ): ssh/5461  ... [continued]: select()) = 1
   810.431 ( 0.002 ms): ssh/5461 clock_gettime(which_clock: BOOTTIME, tp: 0x7ffd7f39f870) = 0
   ^C

Several syscall exit events for syscalls in flight when 'perf trace' started, etc. Saner :-)

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-c3tu5yg204p5mvr9kvwew07n@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-11-21 12:00:31 -03:00
Arnaldo Carvalho de Melo
ed9a77ba77 perf augmented_syscalls: Use pid_filter
Just to test filtering a bunch of pids, now its time to go and get that
hooked up in 'perf trace', right after we load the bpf program, if we
find a "pids_filtered" map defined, we'll populate it with the filtered
pids.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-1i9s27wqqdhafk3fappow84x@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-11-21 12:00:31 -03:00
Arnaldo Carvalho de Melo
77ecb64050 perf augmented_syscalls: Drop 'write', 'poll' for testing without self pid filter
When testing system wide tracing without filtering the syscalls called
by 'perf trace' itself we get into a feedback loop, drop for now those
two syscalls, that are the ones that 'perf trace' does in its loop for
writing the syscalls it intercepts, to help with testing till we get
that filtering in place.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-rkbu536af66dbsfx51sr8yof@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-11-21 12:00:31 -03:00
Arnaldo Carvalho de Melo
66067538e0 perf augmented_syscalls: Remove needless linux/socket.h include
Leftover from when we started augmented_raw_syscalls.c from
tools/perf/examples/bpf/augmented_syscalls.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: e58a0322dbac ("perf examples bpf: Start augmenting raw_syscalls:sys_{start,exit}")
Link: https://lkml.kernel.org/n/tip-pmts9ls2skh8n3zisb4txudd@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-11-21 12:00:31 -03:00
Arnaldo Carvalho de Melo
55f127b431 perf augmented_syscalls: Filter on a hard coded pid
Just to show where we'll hook pid based filters, and what we use to
obtain the current pid, using a BPF getpid() equivalent.

Now we need to remove that hardcoded PID with a BPF hash map, so that we
start by filtering 'perf trace's own PID, implement the --filter-pid
functionality, etc.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-oshrcgcekiyhd0whwisxfvtv@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-11-21 12:00:31 -03:00
Arnaldo Carvalho de Melo
79ef68c7e1 perf augmented_syscalls: Start collecting pathnames in the BPF program
This is the start of having the raw_syscalls:sys_enter BPF handler
collecting pointer arguments, namely pathnames, and with two syscalls
that have that pointer in different arguments, "open" as it as its first
argument, "openat" as the second.

With this in place the existing beautifiers in 'perf trace' works, those
args are shown instead of just the pointer that comes with the syscalls
tracepoints.

This also serves to show and document pitfalls in the process of using
just that place in the kernel (raw_syscalls:sys_enter) plus tables
provided by userspace to collect syscall pointer arguments.

One is the need to use a barrier, as suggested by Edward, to avoid clang
optimizations that make the kernel BPF verifier to refuse loading our
pointer contents collector.

The end result should be a generic eBPF program that works in all
architectures, with the differences amongst archs resolved by the
userspace component, 'perf trace', that should get all its tables
created automatically from the kernel components where they are defined,
via string table constructors for things not expressed in BTF/DWARF
(enums, structs, etc), and otherwise using those observability files
(BTF).

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: Edward Cree <ecree@solarflare.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Yonghong Song <yhs@fb.com>
Link: https://lkml.kernel.org/n/tip-37dz54pmotgpnwg9tb6zuk9j@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-11-05 12:41:10 -03:00
Arnaldo Carvalho de Melo
febf8a3712 perf examples bpf: Start augmenting raw_syscalls:sys_{start,exit}
The previous approach of attaching to each syscall showed how it is
possible to augment tracepoints and use that augmentation, pointer
payloads, in the existing beautifiers in 'perf trace', but for a more
general solution we now will try to augment the main
raw_syscalls:sys_{enter,exit} syscalls, and then pass instructions in
maps so that it knows which syscalls and which pointer contents, and how
many bytes for each of the arguments should be copied.

Start with just the bare minimum to collect what is provided by those
two tracepoints via the __augmented_syscalls__ map + bpf-output perf
event, which results in perf trace showing them without connecting
enter+exit:

  # perf trace -e tools/perf/examples/bpf/augmented_raw_syscalls.c sleep 1
     0.000 sleep/11563 raw_syscalls:sys_exit:NR 59 = 0
     0.019 (         ): sleep/11563 brk() ...
     0.021 sleep/11563 raw_syscalls:sys_exit:NR 12 = 94682642325504
     0.033 (         ): sleep/11563 access(filename:, mode: R) ...
     0.037 sleep/11563 raw_syscalls:sys_exit:NR 21 = -2
     0.041 (         ): sleep/11563 openat(dfd: CWD, filename: , flags: CLOEXEC) ...
     0.044 sleep/11563 raw_syscalls:sys_exit:NR 257 = 3
     0.045 (         ): sleep/11563 fstat(fd: 3, statbuf: 0x7ffdbf7119b0) ...
     0.046 sleep/11563 raw_syscalls:sys_exit:NR 5 = 0
     0.047 (         ): sleep/11563 mmap(len: 103334, prot: READ, flags: PRIVATE, fd: 3) ...
     0.049 sleep/11563 raw_syscalls:sys_exit:NR 9 = 140196285493248
     0.050 (         ): sleep/11563 close(fd: 3) ...
     0.051 sleep/11563 raw_syscalls:sys_exit:NR 3 = 0
     0.059 (         ): sleep/11563 openat(dfd: CWD, filename: , flags: CLOEXEC) ...
     0.062 sleep/11563 raw_syscalls:sys_exit:NR 257 = 3
     0.063 (         ): sleep/11563 read(fd: 3, buf: 0x7ffdbf711b78, count: 832) ...
     0.065 sleep/11563 raw_syscalls:sys_exit:NR 0 = 832
     0.066 (         ): sleep/11563 fstat(fd: 3, statbuf: 0x7ffdbf711a10) ...
     0.067 sleep/11563 raw_syscalls:sys_exit:NR 5 = 0
     0.068 (         ): sleep/11563 mmap(len: 8192, prot: READ|WRITE, flags: PRIVATE|ANONYMOUS) ...
     0.070 sleep/11563 raw_syscalls:sys_exit:NR 9 = 140196285485056
     0.073 (         ): sleep/11563 mmap(len: 3889792, prot: EXEC|READ, flags: PRIVATE|DENYWRITE, fd: 3) ...
     0.076 sleep/11563 raw_syscalls:sys_exit:NR 9 = 140196279463936
     0.077 (         ): sleep/11563 mprotect(start: 0x7f81fd8a8000, len: 2093056) ...
     0.083 sleep/11563 raw_syscalls:sys_exit:NR 10 = 0
     0.084 (         ): sleep/11563 mmap(addr: 0x7f81fdaa7000, len: 24576, prot: READ|WRITE, flags: PRIVATE|FIXED|DENYWRITE, fd: 3, off: 1753088) ...
     0.088 sleep/11563 raw_syscalls:sys_exit:NR 9 = 140196283314176
     0.091 (         ): sleep/11563 mmap(addr: 0x7f81fdaad000, len: 14976, prot: READ|WRITE, flags: PRIVATE|FIXED|ANONYMOUS) ...
     0.093 sleep/11563 raw_syscalls:sys_exit:NR 9 = 140196283338752
     0.097 (         ): sleep/11563 close(fd: 3) ...
     0.098 sleep/11563 raw_syscalls:sys_exit:NR 3 = 0
     0.107 (         ): sleep/11563 arch_prctl(option: 4098, arg2: 140196285490432) ...
     0.108 sleep/11563 raw_syscalls:sys_exit:NR 158 = 0
     0.143 (         ): sleep/11563 mprotect(start: 0x7f81fdaa7000, len: 16384, prot: READ) ...
     0.146 sleep/11563 raw_syscalls:sys_exit:NR 10 = 0
     0.157 (         ): sleep/11563 mprotect(start: 0x561d037e7000, len: 4096, prot: READ) ...
     0.160 sleep/11563 raw_syscalls:sys_exit:NR 10 = 0
     0.163 (         ): sleep/11563 mprotect(start: 0x7f81fdcd5000, len: 4096, prot: READ) ...
     0.165 sleep/11563 raw_syscalls:sys_exit:NR 10 = 0
     0.166 (         ): sleep/11563 munmap(addr: 0x7f81fdcbb000, len: 103334) ...
     0.174 sleep/11563 raw_syscalls:sys_exit:NR 11 = 0
     0.216 (         ): sleep/11563 brk() ...
     0.217 sleep/11563 raw_syscalls:sys_exit:NR 12 = 94682642325504
     0.217 (         ): sleep/11563 brk(brk: 0x561d05453000) ...
     0.219 sleep/11563 raw_syscalls:sys_exit:NR 12 = 94682642460672
     0.220 (         ): sleep/11563 brk() ...
     0.221 sleep/11563 raw_syscalls:sys_exit:NR 12 = 94682642460672
     0.224 (         ): sleep/11563 open(filename: , flags: CLOEXEC) ...
     0.228 sleep/11563 raw_syscalls:sys_exit:NR 2 = 3
     0.229 (         ): sleep/11563 fstat(fd: 3, statbuf: 0x7f81fdaacaa0) ...
     0.230 sleep/11563 raw_syscalls:sys_exit:NR 5 = 0
     0.231 (         ): sleep/11563 mmap(len: 113045344, prot: READ, flags: PRIVATE, fd: 3) ...
     0.234 sleep/11563 raw_syscalls:sys_exit:NR 9 = 140196166418432
     0.237 (         ): sleep/11563 close(fd: 3) ...
     0.238 sleep/11563 raw_syscalls:sys_exit:NR 3 = 0
     0.262 (         ): sleep/11563 nanosleep(rqtp: 0x7ffdbf7126f0) ...
  1000.399 sleep/11563 raw_syscalls:sys_exit:NR 35 = 0
  1000.440 (         ): sleep/11563 close(fd: 1) ...
  1000.447 sleep/11563 raw_syscalls:sys_exit:NR 3 = 0
  1000.454 (         ): sleep/11563 close(fd: 2) ...
  1000.468 (         ): sleep/11563 exit_group(                                                           )
  #

In the next csets we'll connect those events to the existing enter/exit
raw_syscalls handlers in 'perf trace', just like we did with the
syscalls:sys_{enter,exit}_* tracepoints.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-5nl8l4hx1tl9pqdx65nkp6pw@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-11-01 14:11:45 -03:00