| Message ID | 20240922164702.49615-1-kdipendra88@gmail.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Delegated to: | Mikulas Patocka |
| Headers | show |
| Series | Return error code for failure input for sscanf in parse_cblock_range() | expand |
On Mon, Sep 23, 2024 at 12:47 AM Dipendra Khadka <kdipendra88@gmail.com> wrote: > > Smatch reported following: > ''' > drivers/md/dm-cache-target.c:3204 parse_cblock_range() warn: sscanf doesn't return error codes > drivers/md/dm-cache-target.c:3217 parse_cblock_range() warn: sscanf doesn't return error codes > ''' > > Since, the only negative value that is returned by sscanf is -1. > Returning -ENVAL when sscanf returns -1. > > Signed-off-by: Dipendra Khadka <kdipendra88@gmail.com> > --- > drivers/md/dm-cache-target.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c > index 17f0fab1e254..c35d65e310d6 100644 > --- a/drivers/md/dm-cache-target.c > +++ b/drivers/md/dm-cache-target.c > @@ -3200,8 +3200,8 @@ static int parse_cblock_range(struct cache *cache, const char *str, > * Try and parse form (ii) first. > */ > r = sscanf(str, "%llu-%llu%c", &b, &e, &dummy); > - if (r < 0) > - return r; > + if (r == -1) > + return -EINVAL; > > if (r == 2) { > result->begin = to_cblock(b); > @@ -3213,8 +3213,8 @@ static int parse_cblock_range(struct cache *cache, const char *str, > * That didn't work, try form (i). > */ > r = sscanf(str, "%llu%c", &b, &dummy); > - if (r < 0) > - return r; > + if (r == -1) > + return -EINVAL; > > if (r == 1) { > result->begin = to_cblock(b); Could you please clarify how to reproduce unexpected results? From what I observe, the kernel's sscanf doesn't return -1 on an empty input. Even if a negative value other than -EINVAL is returned, it is handled by the callers. Hank > -- > 2.43.0 > >
Hi I skimmed through the sscanf source code and it seems that it can't return a negative value at all. I think, this should be: r = sscanf(str, "%llu-%llu%c", &b, &e, &dummy); if (r != 2) return -EINVAL; Mikulas On Sun, 22 Sep 2024, Dipendra Khadka wrote: > Smatch reported following: > ''' > drivers/md/dm-cache-target.c:3204 parse_cblock_range() warn: sscanf doesn't return error codes > drivers/md/dm-cache-target.c:3217 parse_cblock_range() warn: sscanf doesn't return error codes > ''' > > Since, the only negative value that is returned by sscanf is -1. > Returning -ENVAL when sscanf returns -1. > > Signed-off-by: Dipendra Khadka <kdipendra88@gmail.com> > --- > drivers/md/dm-cache-target.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c > index 17f0fab1e254..c35d65e310d6 100644 > --- a/drivers/md/dm-cache-target.c > +++ b/drivers/md/dm-cache-target.c > @@ -3200,8 +3200,8 @@ static int parse_cblock_range(struct cache *cache, const char *str, > * Try and parse form (ii) first. > */ > r = sscanf(str, "%llu-%llu%c", &b, &e, &dummy); > - if (r < 0) > - return r; > + if (r == -1) > + return -EINVAL; > > if (r == 2) { > result->begin = to_cblock(b); > @@ -3213,8 +3213,8 @@ static int parse_cblock_range(struct cache *cache, const char *str, > * That didn't work, try form (i). > */ > r = sscanf(str, "%llu%c", &b, &dummy); > - if (r < 0) > - return r; > + if (r == -1) > + return -EINVAL; > > if (r == 1) { > result->begin = to_cblock(b); > -- > 2.43.0 >
On Mon, 23 Sep 2024, Ming-Hung Tsai wrote: > On Mon, Sep 23, 2024 at 12:47 AM Dipendra Khadka <kdipendra88@gmail.com> wrote: > > > > Smatch reported following: > > ''' > > drivers/md/dm-cache-target.c:3204 parse_cblock_range() warn: sscanf doesn't return error codes > > drivers/md/dm-cache-target.c:3217 parse_cblock_range() warn: sscanf doesn't return error codes > > ''' > > > > Since, the only negative value that is returned by sscanf is -1. > > Returning -ENVAL when sscanf returns -1. > > > > Signed-off-by: Dipendra Khadka <kdipendra88@gmail.com> > > --- > > drivers/md/dm-cache-target.c | 8 ++++---- > > 1 file changed, 4 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c > > index 17f0fab1e254..c35d65e310d6 100644 > > --- a/drivers/md/dm-cache-target.c > > +++ b/drivers/md/dm-cache-target.c > > @@ -3200,8 +3200,8 @@ static int parse_cblock_range(struct cache *cache, const char *str, > > * Try and parse form (ii) first. > > */ > > r = sscanf(str, "%llu-%llu%c", &b, &e, &dummy); > > - if (r < 0) > > - return r; > > + if (r == -1) > > + return -EINVAL; > > > > if (r == 2) { > > result->begin = to_cblock(b); > > @@ -3213,8 +3213,8 @@ static int parse_cblock_range(struct cache *cache, const char *str, > > * That didn't work, try form (i). > > */ > > r = sscanf(str, "%llu%c", &b, &dummy); > > - if (r < 0) > > - return r; > > + if (r == -1) > > + return -EINVAL; > > > > if (r == 1) { > > result->begin = to_cblock(b); > > > Could you please clarify how to reproduce unexpected results? From > what I observe, the kernel's sscanf doesn't return -1 on an empty > input. Even if a negative value other than -EINVAL is returned, it is > handled by the callers. > > Hank I applied the patch, but I deleted the conditions "if (r == -1) return -EINVAL;" sscanf in the kernel doesn't return negative numbers. Mikulas
Hi, On Mon, 23 Sept 2024 at 20:55, Mikulas Patocka <mpatocka@redhat.com> wrote: > > > > On Mon, 23 Sep 2024, Ming-Hung Tsai wrote: > > > On Mon, Sep 23, 2024 at 12:47 AM Dipendra Khadka <kdipendra88@gmail.com> wrote: > > > > > > Smatch reported following: > > > ''' > > > drivers/md/dm-cache-target.c:3204 parse_cblock_range() warn: sscanf doesn't return error codes > > > drivers/md/dm-cache-target.c:3217 parse_cblock_range() warn: sscanf doesn't return error codes > > > ''' > > > > > > Since, the only negative value that is returned by sscanf is -1. > > > Returning -ENVAL when sscanf returns -1. > > > > > > Signed-off-by: Dipendra Khadka <kdipendra88@gmail.com> > > > --- > > > drivers/md/dm-cache-target.c | 8 ++++---- > > > 1 file changed, 4 insertions(+), 4 deletions(-) > > > > > > diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c > > > index 17f0fab1e254..c35d65e310d6 100644 > > > --- a/drivers/md/dm-cache-target.c > > > +++ b/drivers/md/dm-cache-target.c > > > @@ -3200,8 +3200,8 @@ static int parse_cblock_range(struct cache *cache, const char *str, > > > * Try and parse form (ii) first. > > > */ > > > r = sscanf(str, "%llu-%llu%c", &b, &e, &dummy); > > > - if (r < 0) > > > - return r; > > > + if (r == -1) > > > + return -EINVAL; > > > > > > if (r == 2) { > > > result->begin = to_cblock(b); > > > @@ -3213,8 +3213,8 @@ static int parse_cblock_range(struct cache *cache, const char *str, > > > * That didn't work, try form (i). > > > */ > > > r = sscanf(str, "%llu%c", &b, &dummy); > > > - if (r < 0) > > > - return r; > > > + if (r == -1) > > > + return -EINVAL; > > > > > > if (r == 1) { > > > result->begin = to_cblock(b); > > > > > > Could you please clarify how to reproduce unexpected results? From > > what I observe, the kernel's sscanf doesn't return -1 on an empty > > input. Even if a negative value other than -EINVAL is returned, it is > > handled by the callers. > > > > Hank > > I applied the patch, but I deleted the conditions "if (r == -1) return > -EINVAL;" > > sscanf in the kernel doesn't return negative numbers. > Do I have to send v2 with if (r != 2) return -EINVAL; or what should I do now? > Mikulas Best Regards, Dipendra
On Mon, 23 Sep 2024, Dipendra Khadka wrote: > Hi, > > On Mon, 23 Sept 2024 at 20:55, Mikulas Patocka <mpatocka@redhat.com> wrote: > > > > > > > > On Mon, 23 Sep 2024, Ming-Hung Tsai wrote: > > > > > On Mon, Sep 23, 2024 at 12:47 AM Dipendra Khadka <kdipendra88@gmail.com> wrote: > > > > > > > > Smatch reported following: > > > > ''' > > > > drivers/md/dm-cache-target.c:3204 parse_cblock_range() warn: sscanf doesn't return error codes > > > > drivers/md/dm-cache-target.c:3217 parse_cblock_range() warn: sscanf doesn't return error codes > > > > ''' > > > > > > > > Since, the only negative value that is returned by sscanf is -1. > > > > Returning -ENVAL when sscanf returns -1. > > > > > > > > Signed-off-by: Dipendra Khadka <kdipendra88@gmail.com> > > > > --- > > > > drivers/md/dm-cache-target.c | 8 ++++---- > > > > 1 file changed, 4 insertions(+), 4 deletions(-) > > > > > > > > diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c > > > > index 17f0fab1e254..c35d65e310d6 100644 > > > > --- a/drivers/md/dm-cache-target.c > > > > +++ b/drivers/md/dm-cache-target.c > > > > @@ -3200,8 +3200,8 @@ static int parse_cblock_range(struct cache *cache, const char *str, > > > > * Try and parse form (ii) first. > > > > */ > > > > r = sscanf(str, "%llu-%llu%c", &b, &e, &dummy); > > > > - if (r < 0) > > > > - return r; > > > > + if (r == -1) > > > > + return -EINVAL; > > > > > > > > if (r == 2) { > > > > result->begin = to_cblock(b); > > > > @@ -3213,8 +3213,8 @@ static int parse_cblock_range(struct cache *cache, const char *str, > > > > * That didn't work, try form (i). > > > > */ > > > > r = sscanf(str, "%llu%c", &b, &dummy); > > > > - if (r < 0) > > > > - return r; > > > > + if (r == -1) > > > > + return -EINVAL; > > > > > > > > if (r == 1) { > > > > result->begin = to_cblock(b); > > > > > > > > > Could you please clarify how to reproduce unexpected results? From > > > what I observe, the kernel's sscanf doesn't return -1 on an empty > > > input. Even if a negative value other than -EINVAL is returned, it is > > > handled by the callers. > > > > > > Hank > > > > I applied the patch, but I deleted the conditions "if (r == -1) return > > -EINVAL;" > > > > sscanf in the kernel doesn't return negative numbers. > > > > Do I have to send v2 with > if (r != 2) > return -EINVAL; > > or what should I do now? > > Mikulas > > Best Regards, > Dipendra You can do nothing :) I fixed the patch and I'll send it to Linus in this merge window. Mikulas
On Mon, 23 Sept 2024 at 21:45, Mikulas Patocka <mpatocka@redhat.com> wrote: > > > > On Mon, 23 Sep 2024, Dipendra Khadka wrote: > > > Hi, > > > > On Mon, 23 Sept 2024 at 20:55, Mikulas Patocka <mpatocka@redhat.com> wrote: > > > > > > > > > > > > On Mon, 23 Sep 2024, Ming-Hung Tsai wrote: > > > > > > > On Mon, Sep 23, 2024 at 12:47 AM Dipendra Khadka <kdipendra88@gmail.com> wrote: > > > > > > > > > > Smatch reported following: > > > > > ''' > > > > > drivers/md/dm-cache-target.c:3204 parse_cblock_range() warn: sscanf doesn't return error codes > > > > > drivers/md/dm-cache-target.c:3217 parse_cblock_range() warn: sscanf doesn't return error codes > > > > > ''' > > > > > > > > > > Since, the only negative value that is returned by sscanf is -1. > > > > > Returning -ENVAL when sscanf returns -1. > > > > > > > > > > Signed-off-by: Dipendra Khadka <kdipendra88@gmail.com> > > > > > --- > > > > > drivers/md/dm-cache-target.c | 8 ++++---- > > > > > 1 file changed, 4 insertions(+), 4 deletions(-) > > > > > > > > > > diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c > > > > > index 17f0fab1e254..c35d65e310d6 100644 > > > > > --- a/drivers/md/dm-cache-target.c > > > > > +++ b/drivers/md/dm-cache-target.c > > > > > @@ -3200,8 +3200,8 @@ static int parse_cblock_range(struct cache *cache, const char *str, > > > > > * Try and parse form (ii) first. > > > > > */ > > > > > r = sscanf(str, "%llu-%llu%c", &b, &e, &dummy); > > > > > - if (r < 0) > > > > > - return r; > > > > > + if (r == -1) > > > > > + return -EINVAL; > > > > > > > > > > if (r == 2) { > > > > > result->begin = to_cblock(b); > > > > > @@ -3213,8 +3213,8 @@ static int parse_cblock_range(struct cache *cache, const char *str, > > > > > * That didn't work, try form (i). > > > > > */ > > > > > r = sscanf(str, "%llu%c", &b, &dummy); > > > > > - if (r < 0) > > > > > - return r; > > > > > + if (r == -1) > > > > > + return -EINVAL; > > > > > > > > > > if (r == 1) { > > > > > result->begin = to_cblock(b); > > > > > > > > > > > > Could you please clarify how to reproduce unexpected results? From > > > > what I observe, the kernel's sscanf doesn't return -1 on an empty > > > > input. Even if a negative value other than -EINVAL is returned, it is > > > > handled by the callers. > > > > > > > > Hank > > > > > > I applied the patch, but I deleted the conditions "if (r == -1) return > > > -EINVAL;" > > > > > > sscanf in the kernel doesn't return negative numbers. > > > > > > > Do I have to send v2 with > > if (r != 2) > > return -EINVAL; > > > > or what should I do now? > > > Mikulas > > > > Best Regards, > > Dipendra > > You can do nothing :) > > I fixed the patch and I'll send it to Linus in this merge window. > Oh, ok. Thank you for your time. > Mikulas Best Regards, Dipendra.
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c index 17f0fab1e254..c35d65e310d6 100644 --- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -3200,8 +3200,8 @@ static int parse_cblock_range(struct cache *cache, const char *str, * Try and parse form (ii) first. */ r = sscanf(str, "%llu-%llu%c", &b, &e, &dummy); - if (r < 0) - return r; + if (r == -1) + return -EINVAL; if (r == 2) { result->begin = to_cblock(b); @@ -3213,8 +3213,8 @@ static int parse_cblock_range(struct cache *cache, const char *str, * That didn't work, try form (i). */ r = sscanf(str, "%llu%c", &b, &dummy); - if (r < 0) - return r; + if (r == -1) + return -EINVAL; if (r == 1) { result->begin = to_cblock(b);
Smatch reported following: ''' drivers/md/dm-cache-target.c:3204 parse_cblock_range() warn: sscanf doesn't return error codes drivers/md/dm-cache-target.c:3217 parse_cblock_range() warn: sscanf doesn't return error codes ''' Since, the only negative value that is returned by sscanf is -1. Returning -ENVAL when sscanf returns -1. Signed-off-by: Dipendra Khadka <kdipendra88@gmail.com> --- drivers/md/dm-cache-target.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)