On Mon, Jun 10, 2019 at 03:47:54PM -0300, Arnaldo Carvalho de Melo wrote: [...] > > > I tested with the lastest perf/core branch which contains the patch: > > > 'perf augmented_raw_syscalls: Tell which args are filenames and how > > > many bytes to copy' and got the error as below: > > > > > > # perf trace -e string -e /mnt/linux-kernel/linux-cs-dev/tools/perf/examples/bpf/augmented_raw_syscalls.c > > > Error: Invalid syscall access, chmod, chown, creat, futimesat, lchown, link, lstat, mkdir, mknod, newfstatat, open, readlink, rename, > > > rmdir, stat, statfs, symlink, truncate, unlink > > Humm, I think that we can just make the code that parses the > tools/perf/trace/strace/groups/string file to ignore syscalls it can't > find in the syscall_tbl, i.e. trace those if they exist in the arch. Agree. > > > Hint: try 'perf list syscalls:sys_enter_*' > > > Hint: and: 'man syscalls' > > > > > > So seems mksyscalltbl has not included completely for syscalls, I > > > use below command to generate syscalltbl_arm64[] array and it don't > > > include related entries for access, chmod, chown, etc ... > > So, we need to investigate why is that these are missing, good thing we > have this 'strings' group :-) > > > > You could refer the generated syscalltbl_arm64 in: > > > http://paste.ubuntu.com/p/8Bj7Jkm2mP/ > > > > After digging into this issue on Arm64, below is summary info: > > > > - arm64 uses the header include/uapi/linux/unistd.h to define system > > call numbers, in this header some system calls are not defined (I > > think the reason is these system calls are obsolete at the end) so the > > corresponding strings are missed in the array syscalltbl_native, > > for arm64 the array is defined in the file: > > tools/perf/arch/arm64/include/generated/asm/syscalls.c. > > Yeah, I looked at the 'access' case and indeed it is not present in > include/uapi/asm-generic/unistd.h, which is the place > include/uapi/linux/unistd.h ends up. > > Ok please take a look at the patch at the end of this message, should be ok? > > I tested it by changing the strace/gorups/string file to have a few > unknown syscalls, running it with -v we see: > > [root@quaco perf]# perf trace -v -e string ls > Skipping unknown syscalls: access99, acct99, add_key99 > <SNIP other verbose messages> > normal operation not considering those unknown syscalls. I did testing with the patch, but it failed after I added eBPF event with below command, I even saw segmentation fault; please see below inline comments. perf --debug verbose=10 trace -e string -e \ /mnt/linux-kernel/linux-cs-dev/tools/perf/examples/bpf/augmented_raw_syscalls.c [...] > commit e0b34a78c4ed0a6422f5b2dafa0c8936e537ee41 > Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> > Date: Mon Jun 10 15:37:45 2019 -0300 > > perf trace: Skip unknown syscalls when expanding strace like syscall groups > > We have $INSTALL_DIR/share/perf-core/strace/groups/string files with > syscalls that should be selected when 'string' is used, meaning, in this > case, syscalls that receive as one of its arguments a string, like a > pathname. > > But those were first selected and tested on x86_64, and end up failing > in architectures where some of those syscalls are not available, like > the 'access' syscall on arm64, which makes using 'perf trace -e string' > in such archs to fail. > > Since this the routine doing the validation is used only when reading > such files, do not fail when some syscall is not found in the > syscalltbl, instead just use pr_debug() to register that in case people > are suspicious of problems. > > Now using 'perf trace -e string' should work on arm64, selecting only > the syscalls that have a string and are available on that architecture. > > Reported-by: Leo Yan <leo.yan@xxxxxxxxxx> > Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx> > Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx> > Cc: Alexei Starovoitov <ast@xxxxxxxxxx> > Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx> > Cc: Jiri Olsa <jolsa@xxxxxxxxxx> > Cc: Martin KaFai Lau <kafai@xxxxxx> > Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> > Cc: Mike Leach <mike.leach@xxxxxxxxxx> > Cc: Namhyung Kim <namhyung@xxxxxxxxxx> > Cc: Song Liu <songliubraving@xxxxxx> > Cc: Suzuki K Poulose <suzuki.poulose@xxxxxxx> > Cc: Yonghong Song <yhs@xxxxxx> > Link: https://lkml.kernel.org/n/tip-oa4c2x8p3587jme0g89fyg18@xxxxxxxxxxxxxx > Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> > > diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c > index 1a2a605cf068..eb70a4b71755 100644 > --- a/tools/perf/builtin-trace.c > +++ b/tools/perf/builtin-trace.c > @@ -1529,6 +1529,7 @@ static int trace__read_syscall_info(struct trace *trace, int id) > static int trace__validate_ev_qualifier(struct trace *trace) > { > int err = 0, i; > + bool printed_invalid_prefix = false; > size_t nr_allocated; > struct str_node *pos; > > @@ -1555,14 +1556,15 @@ static int trace__validate_ev_qualifier(struct trace *trace) > if (id >= 0) > goto matches; > > - if (err == 0) { > - fputs("Error:\tInvalid syscall ", trace->output); > - err = -EINVAL; > + if (!printed_invalid_prefix) { > + pr_debug("Skipping unknown syscalls: "); > + printed_invalid_prefix = true; > } else { > - fputs(", ", trace->output); > + pr_debug(", "); > } > > - fputs(sc, trace->output); > + pr_debug("%s", sc); > + continue; Here adds 'continue' so that we want to let ev_qualifier_ids.entries to only store valid system call ids. But this is not sufficient, because we have initialized ev_qualifier_ids.nr at the beginning of the function: trace->ev_qualifier_ids.nr = strlist__nr_entries(trace->ev_qualifier); This sentence will set ids number to the string table's length; but actually some strings are not really supported; this leads to some items in trace->ev_qualifier_ids.entries[] will be not initialized properly. If we want to get neat entries and entry number, I suggest at the beginning of the function we use variable 'nr_allocated' to store string table length and use it to allocate entries: nr_allocated = strlist__nr_entries(trace->ev_qualifier); trace->ev_qualifier_ids.entries = malloc(nr_allocated * sizeof(trace->ev_qualifier_ids.entries[0])); If we find any matched string, then increment the nr field under 'matches' tag: matches: trace->ev_qualifier_ids.nr++; trace->ev_qualifier_ids.entries[i++] = id; This can ensure the entries[0..nr-1] has valid id and we can use ev_qualifier_ids.nr to maintain the valid system call numbers. > } > matches: > trace->ev_qualifier_ids.entries[i++] = id; > @@ -1591,15 +1593,14 @@ static int trace__validate_ev_qualifier(struct trace *trace) > } > } > > - if (err < 0) { > - fputs("\nHint:\ttry 'perf list syscalls:sys_enter_*'" > - "\nHint:\tand: 'man syscalls'\n", trace->output); > -out_free: > - zfree(&trace->ev_qualifier_ids.entries); > - trace->ev_qualifier_ids.nr = 0; > - } > out: > + if (printed_invalid_prefix) > + pr_debug("\n"); > return err; > +out_free: > + zfree(&trace->ev_qualifier_ids.entries); > + trace->ev_qualifier_ids.nr = 0; > + goto out; Nitpick: directly return err and 'goto out' is not necessary. Thanks, Leo Yan > } > > /*
