When running the LTP testsuite one may hit this kernel BUG() with the
write06 testcase:
kernel BUG at mm/filemap.c:2023!
CPU: 1 PID: 8614 Comm: writev01 Not tainted 3.10.0-rc7-64bit-c3000+ #6
IASQ: 0000000000000000 0000000000000000 IAOQ: 00000000401e6e84 00000000401e6e88
IIR: 03ffe01f ISR: 0000000010340000 IOR: 000001fbe0380820
CPU: 1 CR30: 00000000bef80000 CR31: ffffffffffffffff
ORIG_R28: 00000000bdc192c0
IAOQ[0]: iov_iter_advance+0x3c/0xc0
IAOQ[1]: iov_iter_advance+0x40/0xc0
RP(r2): generic_file_buffered_write+0x204/0x3f0
Backtrace:
[<00000000401e764c>] generic_file_buffered_write+0x204/0x3f0
[<00000000401eab24>] __generic_file_aio_write+0x244/0x448
[<00000000401eadc0>] generic_file_aio_write+0x98/0x150
[<000000004024f460>] do_sync_readv_writev+0xc0/0x130
[<000000004025037c>] compat_do_readv_writev+0x12c/0x340
[<00000000402505f8>] compat_writev+0x68/0xa0
[<0000000040251d88>] compat_SyS_writev+0x98/0xf8
Reason for this crash is a gcc miscompilation in the fault handlers of
pa_memcpy() which return the fault address instead of the copied bytes.
Since this seems to be a generic problem with gcc-4.7.x (and below), it's
better to simplify the fault handlers in pa_memcpy to avoid this problem.
Here is a simple reproducer for the problem:
int main(int argc, char **argv)
{
int fd, nbytes;
struct iovec wr_iovec[] = {
{ "TEST STRING ",32},
{ (char*)0x40005000,32} }; // random memory.
fd = open(DATA_FILE, O_RDWR | O_CREAT, 0666);
nbytes = writev(fd, wr_iovec, 2);
printf("return value = %d, errno %d (%s)\n",
nbytes, errno, strerror(errno));
return 0;
}
In addition, John David Anglin wrote:
There is no gcc PR as pa_memcpy is not legitimate C code. There is an
implicit assumption that certain variables will contain correct values
when an exception occurs and the code randomly jumps to one of the
exception blocks. There is no guarantee of this. If a PR was filed, it
would likely be marked as invalid.
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Cc: <stable@vger.kernel.org> # 3.8+
Signed-off-by: Helge Deller <deller@gmx.de>
The Debian experimental linux source package (3.8.5-1) build fails
with the following errors:
...
MODPOST 2016 modules
ERROR: "__ucmpdi2" [fs/btrfs/btrfs.ko] undefined!
ERROR: "__ucmpdi2" [drivers/md/dm-verity.ko] undefined!
The attached patch resolves this problem. It is based on the s390
implementation of ucmpdi2.c.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Avoid this warning, while still prevent gcc from optimizing away the exception code:
arch/parisc/lib/memcpy.c: In function ‘pa_memcpy’:
arch/parisc/lib/memcpy.c:256:2: warning: ‘dummy’ may be used uninitialized in this function [-Wuninitialized]
Signed-off-by: Helge Deller <deller@gmx.de>
parisc copied pci_iomap from generic code, probably to avoid
pulling the rest of iomap.c in. Since that's in
a separate file now, we can reuse the common implementation.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Add CONFIG_DEBUG_STRICT_USER_COPY_CHECKS, copied from the x86
implementation. Tested with 32 and 64bit kernel.
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
The raw_spin* namespace was taken by lockdep for the architecture
specific implementations. raw_spin_* would be the ideal name space for
the spinlocks which are not converted to sleeping locks in preempt-rt.
Linus suggested to convert the raw_ to arch_ locks and cleanup the
name space instead of using an artifical name like core_spin,
atomic_spin or whatever
No functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: linux-arch@vger.kernel.org
Now that the return from alloc_percpu is compatible with the address
of per-cpu vars, it makes sense to hand around the address of per-cpu
variables. To make this sane, we remove the per_cpu__ prefix we used
created to stop people accidentally using these vars directly.
Now we have sparse, we can use that (next patch).
tj: * Updated to convert stuff which were missed by or added after the
original patch.
* Kill per_cpu_var() macro.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
>>>> I think this is what was intended? Note that this patch may affect
>>>> profiling.
>>> it really should be
>>>
>>> - if (likely(t1 & (sizeof(unsigned int)-1)) == 0) {
>>> + if (likely((t1 & (sizeof(unsigned int)-1)) == 0)) {
>>>
>>> randolph
Reported-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Randolph Chung <tausq@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
This trivial patch fixes the following section warnings on PARISC:
> WARNING: vmlinux.o (.text.1): unexpected section name.
>The (.[number]+) following section name are ld generated and not expected.
> Did you forget to use "ax"/"aw" in a .S file?
> Note that for example <linux/init.h> contains
> section definitions for use in .S files.
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
Almost all implementations of pci_iomap() in the kernel, including the generic
lib/iomap.c one, copies the content of a struct resource into unsigned long's
which will break on 32 bits platforms with 64 bits resources.
This fixes all definitions of pci_iomap() to use resource_size_t. I also
"fixed" the 64bits arch for consistency.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This reverts commit efb80e7e09, it turned
out to cause sporadic problems with the timer interrupt on 32-bit kernels.
Needs more investigation.
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
Currently we're hacking libs-y to include libgcc.a, but this has
unforeseen consequences since the userspace libgcc is linked with fpregs
enabled. We need the kernel to stop using fpregs in an uncontrolled manner
to implement lazy fpu state saves.
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
- this macro unifies the code to add exception table entries
- additionally use ENTRY()/ENDPROC() at more places
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
