Earlier in this function we set the last byte of "buf" to NULL so we
always hit the break statement and "i" is never equal to NAME_MAX_LEN.
This patch doesn't change how the driver works but it silences a Smatch
warning and it makes it clearer that we don't write past the end of the
array.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
warning: symbol 'filter_fops' was not declared. Should it be static?
Signed-off-by: Thiago Farina <tfransosi@gmail.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Stephen Rothwell reported the following build warning:
lib/dma-debug.c: In function 'dma_debug_device_change':
lib/dma-debug.c:680: warning: 'return' with no value, in function returning non-void
Introduced by commit f797d9881b
("dma-debug: Do not add notifier when dma debugging is disabled").
Return 0 [notify-done] when disabled. (this is standard bus notifier behavior.)
Signed-off-by: Shaun Ruffell <sruffell@digium.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: <stable@kernel.org>
LKML-Reference: <20091231125624.GA14666@liondog.tnic>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
If CONFIG_HAVE_DMA_API_DEBUG is defined and "dma_debug=off" is
specified on the kernel command line, when you detach a driver from a
device you can cause the following NULL pointer dereference:
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<c0580d35>] dma_debug_device_change+0x5d/0x117
The problem is that the dma_debug_device_change notifier function is
added to the bus notifier chain even though the dma_entry_hash array
was never initialized. If dma debugging is disabled, this patch both
prevents dma_debug_device_change notifiers from being added to the
chain, and additionally ensures that the dma_debug_device_change
notifier function is a no-op.
Cc: stable@kernel.org
Signed-off-by: Shaun Ruffell <sruffell@digium.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
When PAE is enabled in the kernel configuration the size of
phys_addr_t differs from the size of a void pointer. The gcc
prints a warning about that in dma-debug code.
This patch fixes the warning by converting the output to
unsigned long long instead of a pointer.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
While it's debatable whether or not a NULL device argument to
the DMA API functions is valid... since it certainly isn't
valid on devices with an IOMMU... dma-debug really shouldn't be
dereferencing null pointers either.
Guard against that in err_printk and the driver_filter
functions. A Fedora rawhide user was seeing this in one of the
dvb drivers resulting in an oops on boot.
[ A patch has been sent for testing to the driver, but I feel
the dma debugging support should be fixed as well. (There's
still a pile of legacy garbage in the kernel passing null
pointers to dma_{alloc,free}_*. :( ]
Signed-off-by: Kyle McMartin <kyle@redhat.com>
Cc: mchehab@infradead.org
Cc: Joerg Roedel <joerg.roedel@amd.com>
LKML-Reference: <20090820011708.GP25206@bombadil.infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Linus noticed how unclean and buggy the overlap() function is:
- It uses convoluted (and bug-causing) positive checks for
range overlap - instead of using a more natural negative
check.
- Even the positive checks are buggy: a positive intersection
check has four natural cases while we checked only for three,
missing the (addr < start && addr2 == end) case for example.
- The variables are mis-named, making it non-obvious how the
check was done.
- It needlessly uses u64 instead of unsigned long. Since these
are kernel memory pointers and we explicitly exclude highmem
ranges anyway we cannot ever overflow 32 bits, even if we
could. (and on 64-bit it doesnt matter anyway)
All in one, this function needs a total revamp. I used Linus's
suggestions minus the paranoid checks (we cannot overflow really
because if we get totally bad DMA ranges passed far more things
break in the systems than just DMA debugging). I also fixed a
few other small details i noticed.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Alan Cox reported that lockdep runs out of its stack-trace entries
with certain configs:
BUG: MAX_STACK_TRACE_ENTRIES too low
This happens because there are 1024 hash buckets, each with a
separate lock. Lockdep puts each lock into a separate lock class and
tracks them independently.
But in reality we never take more than one of the buckets, so they
really belong into a single lock-class. Annotate the has bucket lock
init accordingly.
[ Impact: reduce the lockdep footprint of dma-debug ]
Reported-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
This patch fixes a bug in the overlap function which returned true if
one region ends exactly before the second region begins. This is no
overlap but the function returned true in that case.
Cc: stable@kernel.org
Reported-by: Andrew Randrianasulu <randrik@mail.ru>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
The current code is not very careful when it builds reference
dma_debug_entries which get passed to hash_bucket_find(). But since this
function changed to a best-fit algorithm these entries have to be more
acurate. This patch adds this higher level of accuracy.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
If we don't check for sg_call_ents the hash_bucket_find function might
still return the wrong dma_debug_entry for sg mappings.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
This patch makes the driver_filter function more readable by
reorganizing the code. The removal of a code code block to an upper
indentation level makes hard-to-read line-wraps unnecessary.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
There is no need to disable/enable irqs on each loop iteration. Just
disable irqs for the whole time the loop runs.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
The pr_* macros are shorter than the old printk(KERN_ ...) variant.
Change the dma-debug code to use the new macros and save a few
unnecessary line breaks. If lines don't break the source code can also
be grepped more easily.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
This patch changes the recent updates to dma-debug to conform with
coding style guidelines of Linux and the -tip tree.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Last patch series introduced some new comment which does not fit the
Kernel comment style guidelines. Fix it with this patch.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
This patch adds the dma-api/driver_filter file to debugfs. The root user
can write a driver name into this file to see only dma-api errors for
that particular driver in the kernel log. Writing an empty string to
that file disables the driver filter.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
This patch adds the state variables for the driver filter and a function
to check if the filter is enabled and matches to the current device. The
check is built into the err_printk function.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
