Revision 9b4fe5fb0bdd8f31f24cbfe77e38ec8155c250c5 authored by Neil Horman on 12 July 2013, 17:35:33 UTC, committed by David S. Miller on 12 July 2013, 23:28:02 UTC
this bug: https://bugzilla.redhat.com/show_bug.cgi?id=951695 Reported a dma debug backtrace: WARNING: at lib/dma-debug.c:937 check_unmap+0x47d/0x930() Hardware name: To Be Filled By O.E.M. via-rhine 0000:00:12.0: DMA-API: device driver failed to check map error[device address=0x0000000075a837b2] [size=90 bytes] [mapped as single] Modules linked in: ip6_tables gspca_spca561 gspca_main videodev media snd_hda_codec_realtek snd_hda_intel i2c_viapro snd_hda_codec snd_hwdep snd_seq ppdev mperf via_rhine coretemp snd_pcm mii microcode snd_page_alloc snd_timer snd_mpu401 snd_mpu401_uart snd_rawmidi snd_seq_device snd soundcore parport_pc parport shpchp ata_generic pata_acpi radeon i2c_algo_bit drm_kms_helper ttm drm pata_via sata_via i2c_core uinput Pid: 295, comm: systemd-journal Not tainted 3.9.0-0.rc6.git2.1.fc20.x86_64 #1 Call Trace: <IRQ> [<ffffffff81068dd0>] warn_slowpath_common+0x70/0xa0 [<ffffffff81068e4c>] warn_slowpath_fmt+0x4c/0x50 [<ffffffff8137ec6d>] check_unmap+0x47d/0x930 [<ffffffff810ace9f>] ? local_clock+0x5f/0x70 [<ffffffff8137f17f>] debug_dma_unmap_page+0x5f/0x70 [<ffffffffa0225edc>] ? rhine_ack_events.isra.14+0x3c/0x50 [via_rhine] [<ffffffffa02275f8>] rhine_napipoll+0x1d8/0xd80 [via_rhine] [<ffffffff815d3d51>] ? net_rx_action+0xa1/0x380 [<ffffffff815d3e22>] net_rx_action+0x172/0x380 [<ffffffff8107345f>] __do_softirq+0xff/0x400 [<ffffffff81073925>] irq_exit+0xb5/0xc0 [<ffffffff81724cd6>] do_IRQ+0x56/0xc0 [<ffffffff81719ff2>] common_interrupt+0x72/0x72 <EOI> [<ffffffff8170ff57>] ? __slab_alloc+0x4c2/0x526 [<ffffffff811992e0>] ? mmap_region+0x2b0/0x5a0 [<ffffffff810d5807>] ? __lock_is_held+0x57/0x80 [<ffffffff811992e0>] ? mmap_region+0x2b0/0x5a0 [<ffffffff811bf1bf>] kmem_cache_alloc+0x2df/0x360 [<ffffffff811992e0>] mmap_region+0x2b0/0x5a0 [<ffffffff811998e6>] do_mmap_pgoff+0x316/0x3d0 [<ffffffff81183ca0>] vm_mmap_pgoff+0x90/0xc0 [<ffffffff81197d6c>] sys_mmap_pgoff+0x4c/0x190 [<ffffffff81367d7e>] ? trace_hardirqs_on_thunk+0x3a/0x3f [<ffffffff8101eb42>] sys_mmap+0x22/0x30 [<ffffffff81722fd9>] system_call_fastpath+0x16/0x1b Usual problem with the usual fix, add the appropriate calls to dma_mapping_error where appropriate Untested, as I don't have hardware, but its pretty straightforward Signed-off-by: Neil Horman <nhorman@tuxdriver.com> CC: David S. Miller <davem@davemloft.net> CC: Roger Luethi <rl@hellgate.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
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sparse.txt
Copyright 2004 Linus Torvalds
Copyright 2004 Pavel Machek <pavel@ucw.cz>
Copyright 2006 Bob Copeland <me@bobcopeland.com>
Using sparse for typechecking
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"__bitwise" is a type attribute, so you have to do something like this:
typedef int __bitwise pm_request_t;
enum pm_request {
PM_SUSPEND = (__force pm_request_t) 1,
PM_RESUME = (__force pm_request_t) 2
};
which makes PM_SUSPEND and PM_RESUME "bitwise" integers (the "__force" is
there because sparse will complain about casting to/from a bitwise type,
but in this case we really _do_ want to force the conversion). And because
the enum values are all the same type, now "enum pm_request" will be that
type too.
And with gcc, all the __bitwise/__force stuff goes away, and it all ends
up looking just like integers to gcc.
Quite frankly, you don't need the enum there. The above all really just
boils down to one special "int __bitwise" type.
So the simpler way is to just do
typedef int __bitwise pm_request_t;
#define PM_SUSPEND ((__force pm_request_t) 1)
#define PM_RESUME ((__force pm_request_t) 2)
and you now have all the infrastructure needed for strict typechecking.
One small note: the constant integer "0" is special. You can use a
constant zero as a bitwise integer type without sparse ever complaining.
This is because "bitwise" (as the name implies) was designed for making
sure that bitwise types don't get mixed up (little-endian vs big-endian
vs cpu-endian vs whatever), and there the constant "0" really _is_
special.
__bitwise__ - to be used for relatively compact stuff (gfp_t, etc.) that
is mostly warning-free and is supposed to stay that way. Warnings will
be generated without __CHECK_ENDIAN__.
__bitwise - noisy stuff; in particular, __le*/__be* are that. We really
don't want to drown in noise unless we'd explicitly asked for it.
Using sparse for lock checking
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The following macros are undefined for gcc and defined during a sparse
run to use the "context" tracking feature of sparse, applied to
locking. These annotations tell sparse when a lock is held, with
regard to the annotated function's entry and exit.
__must_hold - The specified lock is held on function entry and exit.
__acquires - The specified lock is held on function exit, but not entry.
__releases - The specified lock is held on function entry, but not exit.
If the function enters and exits without the lock held, acquiring and
releasing the lock inside the function in a balanced way, no
annotation is needed. The tree annotations above are for cases where
sparse would otherwise report a context imbalance.
Getting sparse
~~~~~~~~~~~~~~
You can get latest released versions from the Sparse homepage at
https://sparse.wiki.kernel.org/index.php/Main_Page
Alternatively, you can get snapshots of the latest development version
of sparse using git to clone..
git://git.kernel.org/pub/scm/devel/sparse/sparse.git
DaveJ has hourly generated tarballs of the git tree available at..
http://www.codemonkey.org.uk/projects/git-snapshots/sparse/
Once you have it, just do
make
make install
as a regular user, and it will install sparse in your ~/bin directory.
Using sparse
~~~~~~~~~~~~
Do a kernel make with "make C=1" to run sparse on all the C files that get
recompiled, or use "make C=2" to run sparse on the files whether they need to
be recompiled or not. The latter is a fast way to check the whole tree if you
have already built it.
The optional make variable CF can be used to pass arguments to sparse. The
build system passes -Wbitwise to sparse automatically. To perform endianness
checks, you may define __CHECK_ENDIAN__:
make C=2 CF="-D__CHECK_ENDIAN__"
These checks are disabled by default as they generate a host of warnings.
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