On Tue, Dec 05, 2017 at 04:56:49PM -0700, Ross Zwisler wrote: > I recently upgraded my compiler from > gcc (GCC) 6.4.1 20170727 (Red Hat 6.4.1-1) > to > gcc (GCC) 7.2.1 20170915 (Red Hat 7.2.1-2) > and started getting a bunch of compiler warnings in io/fsmap.c: > > fsmap.c: In function ‘fsmap_f’: > fsmap.c:228:40: warning: ‘%lld’ directive output may be truncated writing > between 1 and 17 bytes into a region of size between 12 and 28 > [-Wformat-truncation=] > snprintf(bbuf, sizeof(bbuf), "[%lld..%lld]:", > ^~~~ > fsmap.c:228:32: note: directive argument in the range [0, 36028797018963967] > snprintf(bbuf, sizeof(bbuf), "[%lld..%lld]:", > ^~~~~~~~~~~~~~~ > fsmap.c:228:3: note: ‘snprintf’ output between 8 and 40 bytes into a > destination of size 32 > snprintf(bbuf, sizeof(bbuf), "[%lld..%lld]:", > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > (long long)BTOBBT(p->fmr_physical), > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > (long long)BTOBBT(p->fmr_physical + p->fmr_length - 1)); > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > The issue is that 'bbuf' is only defined to be 32 characters wide, but each > signed long long can potentially print as many as 19 characters > (9223372036854775807 is the max value). The format we're using for bbuf is > "[%lld..%lld]:" which has 2 signed long longs plus 6 other characters > "[..]:\0", which means it's possible we'll print up to 44 characters, > overflowing our 32 char buffer. > > Fix this by bumping all the buffer sizes in dump_map_verbose() to 64 > characters. > > Signed-off-by: Ross Zwisler <[email protected]> > Cc: Darrick J. Wong <[email protected]>
Looks ok, Reviewed-by: Darrick J. Wong <[email protected]> > Fixes: 3fcab549a234 ("xfs_io: support the new getfsmap ioctl") > --- > io/fsmap.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/io/fsmap.c b/io/fsmap.c > index 448fb535..3d8a6700 100644 > --- a/io/fsmap.c > +++ b/io/fsmap.c > @@ -184,8 +184,8 @@ dump_map_verbose( > off64_t agoff, bperag; > int foff_w, boff_w, aoff_w, tot_w, agno_w, own_w; > int nr_w, dev_w; > - char rbuf[32], bbuf[32], abuf[32], obuf[32]; > - char nbuf[32], dbuf[32], gbuf[32]; > + char rbuf[64], bbuf[64], abuf[64], obuf[64]; > + char nbuf[64], dbuf[64], gbuf[64]; > char owner[OWNER_BUF_SZ]; > int sunit, swidth; > int flg = 0; > -- > 2.14.3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html _______________________________________________ Linux-nvdimm mailing list [email protected] https://lists.01.org/mailman/listinfo/linux-nvdimm
