From: Dave Chinner <david@fromorbit.com>
To: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>,
"Darrick J . Wong" <darrick.wong@oracle.com>,
linux-nvdimm <linux-nvdimm@lists.01.org>,
fstests <fstests@vger.kernel.org>,
linux-xfs <linux-xfs@vger.kernel.org>
Subject: Re: [xfsprogs PATCH v2 1/3] xfs_io: fix compiler warnings in getfsmap code
Date: Wed, 6 Dec 2017 11:27:43 +1100 [thread overview]
Message-ID: <20171206002743.GC5858@dastard> (raw)
In-Reply-To: <20171205235651.17102-2-ross.zwisler@linux.intel.com>
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 <ross.zwisler@linux.intel.com>
> Cc: Darrick J. Wong <darrick.wong@oracle.com>
> Fixes: 3fcab549a234 ("xfs_io: support the new getfsmap ioctl")
FYI, I posted a fix for this weeks ago. I think Eric has already
picked it up, but it hasn't been pushed out into the for-next branch
yet.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
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WARNING: multiple messages have this Message-ID (diff)
From: Dave Chinner <david@fromorbit.com>
To: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: linux-xfs <linux-xfs@vger.kernel.org>,
linux-nvdimm <linux-nvdimm@lists.01.org>,
fstests <fstests@vger.kernel.org>, Jan Kara <jack@suse.cz>,
Dan Williams <dan.j.williams@intel.com>,
"Darrick J . Wong" <darrick.wong@oracle.com>
Subject: Re: [xfsprogs PATCH v2 1/3] xfs_io: fix compiler warnings in getfsmap code
Date: Wed, 6 Dec 2017 11:27:43 +1100 [thread overview]
Message-ID: <20171206002743.GC5858@dastard> (raw)
In-Reply-To: <20171205235651.17102-2-ross.zwisler@linux.intel.com>
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 <ross.zwisler@linux.intel.com>
> Cc: Darrick J. Wong <darrick.wong@oracle.com>
> Fixes: 3fcab549a234 ("xfs_io: support the new getfsmap ioctl")
FYI, I posted a fix for this weeks ago. I think Eric has already
picked it up, but it hasn't been pushed out into the for-next branch
yet.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2017-12-06 0:23 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-05 23:56 [xfsprogs PATCH v2 0/3] Add necessary items for MAP_SYNC testing Ross Zwisler
2017-12-05 23:56 ` Ross Zwisler
2017-12-05 23:56 ` [xfsprogs PATCH v2 1/3] xfs_io: fix compiler warnings in getfsmap code Ross Zwisler
2017-12-05 23:56 ` Ross Zwisler
2017-12-06 0:03 ` Darrick J. Wong
2017-12-06 0:03 ` Darrick J. Wong
2017-12-06 0:27 ` Dave Chinner [this message]
2017-12-06 0:27 ` Dave Chinner
2017-12-06 13:59 ` Eric Sandeen
2017-12-06 13:59 ` Eric Sandeen
2017-12-06 20:10 ` Ross Zwisler
2017-12-06 20:10 ` Ross Zwisler
2017-12-06 20:47 ` Darrick J. Wong
2017-12-06 20:47 ` Darrick J. Wong
2017-12-06 20:58 ` Ross Zwisler
2017-12-06 20:58 ` Ross Zwisler
2017-12-05 23:56 ` [xfsprogs PATCH v2 2/3] xfs_io: add MAP_SYNC support to mmap() Ross Zwisler
2017-12-05 23:56 ` Ross Zwisler
2017-12-21 17:09 ` Darrick J. Wong
2017-12-21 17:09 ` Darrick J. Wong
2017-12-21 17:41 ` Ross Zwisler
2017-12-21 17:41 ` Ross Zwisler
2017-12-21 17:46 ` Darrick J. Wong
2017-12-21 17:46 ` Darrick J. Wong
2017-12-05 23:56 ` [xfsprogs PATCH v2 3/3] xfs_io: add a new 'log_writes' command Ross Zwisler
2017-12-05 23:56 ` Ross Zwisler
2017-12-06 0:29 ` Dave Chinner
2017-12-06 0:29 ` Dave Chinner
2017-12-06 4:38 ` Ross Zwisler
2017-12-06 4:38 ` Ross Zwisler
2017-12-06 4:41 ` Ross Zwisler
2017-12-06 4:41 ` Ross Zwisler
2017-12-06 5:43 ` Dave Chinner
2017-12-06 5:43 ` Dave Chinner
2017-12-06 18:13 ` [xfsprogs PATCH v3 " Ross Zwisler
2017-12-06 18:13 ` Ross Zwisler
2017-12-21 17:14 ` Darrick J. Wong
2017-12-21 17:14 ` Darrick J. Wong
2017-12-13 16:45 ` [xfsprogs PATCH v2 0/3] Add necessary items for MAP_SYNC testing Ross Zwisler
2017-12-13 16:45 ` Ross Zwisler
2017-12-21 16:55 ` Ross Zwisler
2017-12-21 16:55 ` Ross Zwisler
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