[PATCH 08/33] perf trace beauty ioctl: Fix off-by-one error in cmd->string table

From: Arnaldo Carvalho de Melo
Date: Mon Aug 26 2019 - 21:37:12 EST

From: Benjamin Peterson <benjamin@xxxxxxxxxx>

While tracing a program that calls isatty(3), I noticed that strace
reported TCGETS for the request argument of the underlying ioctl(2)
syscall while perf trace reported TCSETS. strace is corrrect. The bug in
perf was due to the tty ioctl beauty table starting at 0x5400 rather
than 0x5401.

Committer testing:

Using augmented_raw_syscalls.o and settings to make 'perf trace'
use strace formatting, i.e. with this in ~/.perfconfig

# cat ~/.perfconfig
add_events = /home/acme/git/linux/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

# strace -e ioctl stty > /dev/null
ioctl(0, TCGETS, {B38400 opost isig icanon echo ...}) = 0
ioctl(1, TIOCGWINSZ, 0x7fff8a9b0860) = -1 ENOTTY (Inappropriate ioctl for device)
ioctl(1, TCGETS, 0x7fff8a9b0540) = -1 ENOTTY (Inappropriate ioctl for device)
+++ exited with 0 +++


# perf trace -e ioctl stty > /dev/null
ioctl(0, TCSETS, 0x7fff2cf79f20) = 0
ioctl(1, TIOCSWINSZ, 0x7fff2cf79f40) = -1 ENOTTY (Inappropriate ioctl for device)
ioctl(1, TCSETS, 0x7fff2cf79c20) = -1 ENOTTY (Inappropriate ioctl for device)


# perf trace -e ioctl stty > /dev/null
ioctl(0, TCGETS, 0x7ffed0763920) = 0
ioctl(1, TIOCGWINSZ, 0x7ffed0763940) = -1 ENOTTY (Inappropriate ioctl for device)
ioctl(1, TCGETS, 0x7ffed0763620) = -1 ENOTTY (Inappropriate ioctl for device)

Signed-off-by: Benjamin Peterson <benjamin@xxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Fixes: 1cc47f2d46206d67285aea0ca7e8450af571da13 ("perf trace beauty ioctl: Improve 'cmd' beautifier")
Link: http://lkml.kernel.org/r/20190823033625.18814-1-benjamin@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
tools/perf/trace/beauty/ioctl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/trace/beauty/ioctl.c b/tools/perf/trace/beauty/ioctl.c
index 52242fa4072b..e19eb6ea361d 100644
--- a/tools/perf/trace/beauty/ioctl.c
+++ b/tools/perf/trace/beauty/ioctl.c
@@ -21,7 +21,7 @@
static size_t ioctl__scnprintf_tty_cmd(int nr, int dir, char *bf, size_t size)
static const char *ioctl_tty_cmd[] = {