| Message ID | 20210712215535.1471256-4-richard.henderson@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Fixes for clang-13 plus tcg/ppc | expand |
On Mon, Jul 12, 2021 at 02:55:27PM -0700, Richard Henderson wrote: > From clang-13: > util/selfmap.c:26:21: error: variable 'errors' set but not used \ > [-Werror,-Wunused-but-set-variable] > > Quite right of course, but there's no reason not to check errors. > > First, incrementing errors is incorrect, because qemu_strtoul > returns an errno not a count -- just or them together so that > we have a non-zero value at the end. > > Second, if we have an error, do not add the struct to the list, > but free it instead. > > Cc: Alex Bennée <alex.bennee@linaro.org> > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > --- > util/selfmap.c | 28 ++++++++++++++++------------ > 1 file changed, 16 insertions(+), 12 deletions(-) > > diff --git a/util/selfmap.c b/util/selfmap.c > index 2ec99dfdda..0178c2ff8b 100644 > --- a/util/selfmap.c > +++ b/util/selfmap.c > @@ -23,29 +23,33 @@ GSList *read_self_maps(void) > gchar **fields = g_strsplit(lines[i], " ", 6); > if (g_strv_length(fields) > 4) { > MapInfo *e = g_new0(MapInfo, 1); > - int errors; > + int errors = 0; > const char *end; > > - errors = qemu_strtoul(fields[0], &end, 16, &e->start); > - errors += qemu_strtoul(end + 1, NULL, 16, &e->end); > + errors |= qemu_strtoul(fields[0], &end, 16, &e->start); > + errors |= qemu_strtoul(end + 1, NULL, 16, &e->end); > > e->is_read = fields[1][0] == 'r'; > e->is_write = fields[1][1] == 'w'; > e->is_exec = fields[1][2] == 'x'; > e->is_priv = fields[1][3] == 'p'; > > - errors += qemu_strtoul(fields[2], NULL, 16, &e->offset); > + errors |= qemu_strtoul(fields[2], NULL, 16, &e->offset); > e->dev = g_strdup(fields[3]); e->dev now contains malloc'd memory... > - errors += qemu_strtou64(fields[4], NULL, 10, &e->inode); > + errors |= qemu_strtou64(fields[4], NULL, 10, &e->inode); ...and if this qemu_strtou64 fails... > > - /* > - * The last field may have leading spaces which we > - * need to strip. > - */ > - if (g_strv_length(fields) == 6) { > - e->path = g_strdup(g_strchug(fields[5])); > + if (!errors) { > + /* > + * The last field may have leading spaces which we > + * need to strip. > + */ > + if (g_strv_length(fields) == 6) { > + e->path = g_strdup(g_strchug(fields[5])); > + } > + map_info = g_slist_prepend(map_info, e); > + } else { > + g_free(e); ...you've now leaked it. Oops. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org
On 7/13/21 9:06 AM, Eric Blake wrote: >> e->dev = g_strdup(fields[3]); > > e->dev now contains malloc'd memory... > >> - errors += qemu_strtou64(fields[4], NULL, 10, &e->inode); >> + errors |= qemu_strtou64(fields[4], NULL, 10, &e->inode); > > ...and if this qemu_strtou64 fails... > >> >> - /* >> - * The last field may have leading spaces which we >> - * need to strip. >> - */ >> - if (g_strv_length(fields) == 6) { >> - e->path = g_strdup(g_strchug(fields[5])); >> + if (!errors) { >> + /* >> + * The last field may have leading spaces which we >> + * need to strip. >> + */ >> + if (g_strv_length(fields) == 6) { >> + e->path = g_strdup(g_strchug(fields[5])); >> + } >> + map_info = g_slist_prepend(map_info, e); >> + } else { >> + g_free(e); > > ...you've now leaked it. Oops. Yep, thanks. r~
diff --git a/util/selfmap.c b/util/selfmap.c index 2ec99dfdda..0178c2ff8b 100644 --- a/util/selfmap.c +++ b/util/selfmap.c @@ -23,29 +23,33 @@ GSList *read_self_maps(void) gchar **fields = g_strsplit(lines[i], " ", 6); if (g_strv_length(fields) > 4) { MapInfo *e = g_new0(MapInfo, 1); - int errors; + int errors = 0; const char *end; - errors = qemu_strtoul(fields[0], &end, 16, &e->start); - errors += qemu_strtoul(end + 1, NULL, 16, &e->end); + errors |= qemu_strtoul(fields[0], &end, 16, &e->start); + errors |= qemu_strtoul(end + 1, NULL, 16, &e->end); e->is_read = fields[1][0] == 'r'; e->is_write = fields[1][1] == 'w'; e->is_exec = fields[1][2] == 'x'; e->is_priv = fields[1][3] == 'p'; - errors += qemu_strtoul(fields[2], NULL, 16, &e->offset); + errors |= qemu_strtoul(fields[2], NULL, 16, &e->offset); e->dev = g_strdup(fields[3]); - errors += qemu_strtou64(fields[4], NULL, 10, &e->inode); + errors |= qemu_strtou64(fields[4], NULL, 10, &e->inode); - /* - * The last field may have leading spaces which we - * need to strip. - */ - if (g_strv_length(fields) == 6) { - e->path = g_strdup(g_strchug(fields[5])); + if (!errors) { + /* + * The last field may have leading spaces which we + * need to strip. + */ + if (g_strv_length(fields) == 6) { + e->path = g_strdup(g_strchug(fields[5])); + } + map_info = g_slist_prepend(map_info, e); + } else { + g_free(e); } - map_info = g_slist_prepend(map_info, e); } g_strfreev(fields);
From clang-13: util/selfmap.c:26:21: error: variable 'errors' set but not used \ [-Werror,-Wunused-but-set-variable] Quite right of course, but there's no reason not to check errors. First, incrementing errors is incorrect, because qemu_strtoul returns an errno not a count -- just or them together so that we have a non-zero value at the end. Second, if we have an error, do not add the struct to the list, but free it instead. Cc: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> --- util/selfmap.c | 28 ++++++++++++++++------------ 1 file changed, 16 insertions(+), 12 deletions(-) -- 2.25.1