linux.git, branch v3.18.9

Linux 3.18.9

2015-03-06T22:53:42+00:00

quota: Store maximum space limit in bytes

2015-03-06T22:53:06+00:00

commit b10a08194c2b615955dfab2300331a90ae9344c7 upstream.

Currently maximum space limit quota format supports is in blocks however
since we store space limits in bytes, this is somewhat confusing. So
store the maximum limit in bytes as well. Also rename the field to match
the new unit and related inode field to match the new naming scheme.

Reviewed-by: Christoph Hellwig 
Signed-off-by: Jan Kara 
Signed-off-by: Greg Kroah-Hartman

x86/irq: Fix regression caused by commit b568b8601f05

2015-03-06T22:53:06+00:00

commit 1ea76fbadd667b19c4fa4466f3a3b55a505e83d9 upstream.

Commit b568b8601f05 ("Treat SCI interrupt as normal GSI interrupt")
accidently removes support of legacy PIC interrupt when fixing a
regression for Xen, which causes a nasty regression on HP/Compaq
nc6000 where we fail to register the ACPI interrupt, and thus
lose eg. thermal notifications leading a potentially overheated
machine.

So reintroduce support of legacy PIC based ACPI SCI interrupt.

Reported-by: Ville Syrjälä 
Tested-by: Ville Syrjälä 
Signed-off-by: Jiang Liu 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Pavel Machek 
Cc: H. Peter Anvin 
Cc: Len Brown 
Cc: Linus Torvalds 
Cc: Rafael J. Wysocki 
Cc: Sander Eikelenboom 
Cc: linux-pm@vger.kernel.org
Link: http://lkml.kernel.org/r/1424052673-22974-1-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

x86: pmc-atom: Assign debugfs node as soon as possible

2015-03-06T22:53:06+00:00

commit 1b43d7125f3b6f7d46e72da64f65f3187a83b66b upstream.

pmc_dbgfs_unregister() will be called when pmc->dbgfs_dir is unconditionally
NULL on error path in pmc_dbgfs_register(). To prevent this we move the
assignment to where is should be.

Fixes: f855911c1f48 (x86/pmc_atom: Expose PMC device state and platform sleep state)
Reported-by: Thomas Gleixner 
Signed-off-by: Andy Shevchenko 
Cc: Aubrey Li 
Cc: Rafael J. Wysocki 
Cc: Kumar P. Mahesh 
Link: http://lkml.kernel.org/r/1421253575-22509-2-git-send-email-andriy.shevchenko@linux.intel.com
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

x86, mm/ASLR: Fix stack randomization on 64-bit systems

2015-03-06T22:53:06+00:00

commit 4e7c22d447bb6d7e37bfe39ff658486ae78e8d77 upstream.

The issue is that the stack for processes is not properly randomized on
64 bit architectures due to an integer overflow.

The affected function is randomize_stack_top() in file
"fs/binfmt_elf.c":

  static unsigned long randomize_stack_top(unsigned long stack_top)
  {
           unsigned int random_variable = 0;

           if ((current->flags & PF_RANDOMIZE) &&
                   !(current->personality & ADDR_NO_RANDOMIZE)) {
                   random_variable = get_random_int() & STACK_RND_MASK;
                   random_variable <<= PAGE_SHIFT;
           }
           return PAGE_ALIGN(stack_top) + random_variable;
           return PAGE_ALIGN(stack_top) - random_variable;
  }

Note that, it declares the "random_variable" variable as "unsigned int".
Since the result of the shifting operation between STACK_RND_MASK (which
is 0x3fffff on x86_64, 22 bits) and PAGE_SHIFT (which is 12 on x86_64):

	  random_variable <<= PAGE_SHIFT;

then the two leftmost bits are dropped when storing the result in the
"random_variable". This variable shall be at least 34 bits long to hold
the (22+12) result.

These two dropped bits have an impact on the entropy of process stack.
Concretely, the total stack entropy is reduced by four: from 2^28 to
2^30 (One fourth of expected entropy).

This patch restores back the entropy by correcting the types involved
in the operations in the functions randomize_stack_top() and
stack_maxrandom_size().

The successful fix can be tested with:

  $ for i in `seq 1 10`; do cat /proc/self/maps | grep stack; done
  7ffeda566000-7ffeda587000 rw-p 00000000 00:00 0                          [stack]
  7fff5a332000-7fff5a353000 rw-p 00000000 00:00 0                          [stack]
  7ffcdb7a1000-7ffcdb7c2000 rw-p 00000000 00:00 0                          [stack]
  7ffd5e2c4000-7ffd5e2e5000 rw-p 00000000 00:00 0                          [stack]
  ...

Once corrected, the leading bytes should be between 7ffc and 7fff,
rather than always being 7fff.

Signed-off-by: Hector Marco-Gisbert 
Signed-off-by: Ismael Ripoll 
[ Rebased, fixed 80 char bugs, cleaned up commit message, added test example and CVE ]
Signed-off-by: Kees Cook 
Cc: Linus Torvalds 
Cc: Andrew Morton 
Cc: Al Viro 
Fixes: CVE-2015-1593
Link: http://lkml.kernel.org/r/20150214173350.GA18393@www.outflux.net
Signed-off-by: Borislav Petkov 
Signed-off-by: Greg Kroah-Hartman

x86/efi: Avoid triple faults during EFI mixed mode calls

2015-03-06T22:53:06+00:00

commit 96738c69a7fcdbf0d7c9df0c8a27660011e82a7b upstream.

Andy pointed out that if an NMI or MCE is received while we're in the
middle of an EFI mixed mode call a triple fault will occur. This can
happen, for example, when issuing an EFI mixed mode call while running
perf.

The reason for the triple fault is that we execute the mixed mode call
in 32-bit mode with paging disabled but with 64-bit kernel IDT handlers
installed throughout the call.

At Andy's suggestion, stop playing the games we currently do at runtime,
such as disabling paging and installing a 32-bit GDT for __KERNEL_CS. We
can simply switch to the __KERNEL32_CS descriptor before invoking
firmware services, and run in compatibility mode. This way, if an
NMI/MCE does occur the kernel IDT handler will execute correctly, since
it'll jump to __KERNEL_CS automatically.

However, this change is only possible post-ExitBootServices(). Before
then the firmware "owns" the machine and expects for its 32-bit IDT
handlers to be left intact to service interrupts, etc.

So, we now need to distinguish between early boot and runtime
invocations of EFI services. During early boot, we need to restore the
GDT that the firmware expects to be present. We can only jump to the
__KERNEL32_CS code segment for mixed mode calls after ExitBootServices()
has been invoked.

A liberal sprinkling of comments in the thunking code should make the
differences in early and late environments more apparent.

Reported-by: Andy Lutomirski 
Tested-by: Borislav Petkov 
Signed-off-by: Matt Fleming 
Signed-off-by: Greg Kroah-Hartman

blk-throttle: check stats_cpu before reading it from sysfs

2015-03-06T22:53:05+00:00

commit 045c47ca306acf30c740c285a77a4b4bda6be7c5 upstream.

When reading blkio.throttle.io_serviced in a recently created blkio
cgroup, it's possible to race against the creation of a throttle policy,
which delays the allocation of stats_cpu.

Like other functions in the throttle code, just checking for a NULL
stats_cpu prevents the following oops caused by that race.

[ 1117.285199] Unable to handle kernel paging request for data at address 0x7fb4d0020
[ 1117.285252] Faulting instruction address: 0xc0000000003efa2c
[ 1137.733921] Oops: Kernel access of bad area, sig: 11 [#1]
[ 1137.733945] SMP NR_CPUS=2048 NUMA PowerNV
[ 1137.734025] Modules linked in: bridge stp llc kvm_hv kvm binfmt_misc autofs4
[ 1137.734102] CPU: 3 PID: 5302 Comm: blkcgroup Not tainted 3.19.0 #5
[ 1137.734132] task: c000000f1d188b00 ti: c000000f1d210000 task.ti: c000000f1d210000
[ 1137.734167] NIP: c0000000003efa2c LR: c0000000003ef9f0 CTR: c0000000003ef980
[ 1137.734202] REGS: c000000f1d213500 TRAP: 0300   Not tainted  (3.19.0)
[ 1137.734230] MSR: 9000000000009032   CR: 42008884  XER: 20000000
[ 1137.734325] CFAR: 0000000000008458 DAR: 00000007fb4d0020 DSISR: 40000000 SOFTE: 0
GPR00: c0000000003ed3a0 c000000f1d213780 c000000000c59538 0000000000000000
GPR04: 0000000000000800 0000000000000000 0000000000000000 0000000000000000
GPR08: ffffffffffffffff 00000007fb4d0020 00000007fb4d0000 c000000000780808
GPR12: 0000000022000888 c00000000fdc0d80 0000000000000000 0000000000000000
GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR20: 000001003e120200 c000000f1d5b0cc0 0000000000000200 0000000000000000
GPR24: 0000000000000001 c000000000c269e0 0000000000000020 c000000f1d5b0c80
GPR28: c000000000ca3a08 c000000000ca3dec c000000f1c667e00 c000000f1d213850
[ 1137.734886] NIP [c0000000003efa2c] .tg_prfill_cpu_rwstat+0xac/0x180
[ 1137.734915] LR [c0000000003ef9f0] .tg_prfill_cpu_rwstat+0x70/0x180
[ 1137.734943] Call Trace:
[ 1137.734952] [c000000f1d213780] [d000000005560520] 0xd000000005560520 (unreliable)
[ 1137.734996] [c000000f1d2138a0] [c0000000003ed3a0] .blkcg_print_blkgs+0xe0/0x1a0
[ 1137.735039] [c000000f1d213960] [c0000000003efb50] .tg_print_cpu_rwstat+0x50/0x70
[ 1137.735082] [c000000f1d2139e0] [c000000000104b48] .cgroup_seqfile_show+0x58/0x150
[ 1137.735125] [c000000f1d213a70] [c0000000002749dc] .kernfs_seq_show+0x3c/0x50
[ 1137.735161] [c000000f1d213ae0] [c000000000218630] .seq_read+0xe0/0x510
[ 1137.735197] [c000000f1d213bd0] [c000000000275b04] .kernfs_fop_read+0x164/0x200
[ 1137.735240] [c000000f1d213c80] [c0000000001eb8e0] .__vfs_read+0x30/0x80
[ 1137.735276] [c000000f1d213cf0] [c0000000001eb9c4] .vfs_read+0x94/0x1b0
[ 1137.735312] [c000000f1d213d90] [c0000000001ebb38] .SyS_read+0x58/0x100
[ 1137.735349] [c000000f1d213e30] [c000000000009218] syscall_exit+0x0/0x98
[ 1137.735383] Instruction dump:
[ 1137.735405] 7c6307b4 7f891800 409d00b8 60000000 60420000 3d420004 392a63b0 786a1f24
[ 1137.735471] 7d49502a e93e01c8 7d495214 7d2ad214 <7cead02a> e9090008 e9490010 e9290018

And here is one code that allows to easily reproduce this, although this
has first been found by running docker.

void run(pid_t pid)
{
	int n;
	int status;
	int fd;
	char *buffer;
	buffer = memalign(BUFFER_ALIGN, BUFFER_SIZE);
	n = snprintf(buffer, BUFFER_SIZE, "%d\n", pid);
	fd = open(CGPATH "/test/tasks", O_WRONLY);
	write(fd, buffer, n);
	close(fd);
	if (fork() > 0) {
		fd = open("/dev/sda", O_RDONLY | O_DIRECT);
		read(fd, buffer, 512);
		close(fd);
		wait(&status);
	} else {
		fd = open(CGPATH "/test/blkio.throttle.io_serviced", O_RDONLY);
		n = read(fd, buffer, BUFFER_SIZE);
		close(fd);
	}
	free(buffer);
	exit(0);
}

void test(void)
{
	int status;
	mkdir(CGPATH "/test", 0666);
	if (fork() > 0)
		wait(&status);
	else
		run(getpid());
	rmdir(CGPATH "/test");
}

int main(int argc, char **argv)
{
	int i;
	for (i = 0; i < NR_TESTS; i++)
		test();
	return 0;
}

Reported-by: Ricardo Marin Matinata 
Signed-off-by: Thadeu Lima de Souza Cascardo 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

Btrfs: fix fsync data loss after adding hard link to inode

2015-03-06T22:53:05+00:00

commit 1a4bcf470c886b955adf36486f4c86f2441d85cb upstream.

We have a scenario where after the fsync log replay we can lose file data
that had been previously fsync'ed if we added an hard link for our inode
and after that we sync'ed the fsync log (for example by fsync'ing some
other file or directory).

This is because when adding an hard link we updated the inode item in the
log tree with an i_size value of 0. At that point the new inode item was
in memory only and a subsequent fsync log replay would not make us lose
the file data. However if after adding the hard link we sync the log tree
to disk, by fsync'ing some other file or directory for example, we ended
up losing the file data after log replay, because the inode item in the
persisted log tree had an an i_size of zero.

This is easy to reproduce, and the following excerpt from my test for
xfstests shows this:

  _scratch_mkfs >> $seqres.full 2>&1
  _init_flakey
  _mount_flakey

  # Create one file with data and fsync it.
  # This made the btrfs fsync log persist the data and the inode metadata with
  # a correct inode->i_size (4096 bytes).
  $XFS_IO_PROG -f -c "pwrite -S 0xaa -b 4K 0 4K" -c "fsync" \
       $SCRATCH_MNT/foo | _filter_xfs_io

  # Now add one hard link to our file. This made the btrfs code update the fsync
  # log, in memory only, with an inode metadata having a size of 0.
  ln $SCRATCH_MNT/foo $SCRATCH_MNT/foo_link

  # Now force persistence of the fsync log to disk, for example, by fsyncing some
  # other file.
  touch $SCRATCH_MNT/bar
  $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/bar

  # Before a power loss or crash, we could read the 4Kb of data from our file as
  # expected.
  echo "File content before:"
  od -t x1 $SCRATCH_MNT/foo

  # Simulate a crash/power loss.
  _load_flakey_table $FLAKEY_DROP_WRITES
  _unmount_flakey

  _load_flakey_table $FLAKEY_ALLOW_WRITES
  _mount_flakey

  # After the fsync log replay, because the fsync log had a value of 0 for our
  # inode's i_size, we couldn't read anymore the 4Kb of data that we previously
  # wrote and fsync'ed. The size of the file became 0 after the fsync log replay.
  echo "File content after:"
  od -t x1 $SCRATCH_MNT/foo

Another alternative test, that doesn't need to fsync an inode in the same
transaction it was created, is:

  _scratch_mkfs >> $seqres.full 2>&1
  _init_flakey
  _mount_flakey

  # Create our test file with some data.
  $XFS_IO_PROG -f -c "pwrite -S 0xaa -b 8K 0 8K" \
       $SCRATCH_MNT/foo | _filter_xfs_io

  # Make sure the file is durably persisted.
  sync

  # Append some data to our file, to increase its size.
  $XFS_IO_PROG -f -c "pwrite -S 0xcc -b 4K 8K 4K" \
       $SCRATCH_MNT/foo | _filter_xfs_io

  # Fsync the file, so from this point on if a crash/power failure happens, our
  # new data is guaranteed to be there next time the fs is mounted.
  $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo

  # Add one hard link to our file. This made btrfs write into the in memory fsync
  # log a special inode with generation 0 and an i_size of 0 too. Note that this
  # didn't update the inode in the fsync log on disk.
  ln $SCRATCH_MNT/foo $SCRATCH_MNT/foo_link

  # Now make sure the in memory fsync log is durably persisted.
  # Creating and fsync'ing another file will do it.
  touch $SCRATCH_MNT/bar
  $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/bar

  # As expected, before the crash/power failure, we should be able to read the
  # 12Kb of file data.
  echo "File content before:"
  od -t x1 $SCRATCH_MNT/foo

  # Simulate a crash/power loss.
  _load_flakey_table $FLAKEY_DROP_WRITES
  _unmount_flakey

  _load_flakey_table $FLAKEY_ALLOW_WRITES
  _mount_flakey

  # After mounting the fs again, the fsync log was replayed.
  # The btrfs fsync log replay code didn't update the i_size of the persisted
  # inode because the inode item in the log had a special generation with a
  # value of 0 (and it couldn't know the correct i_size, since that inode item
  # had a 0 i_size too). This made the last 4Kb of file data inaccessible and
  # effectively lost.
  echo "File content after:"
  od -t x1 $SCRATCH_MNT/foo

This isn't a new issue/regression. This problem has been around since the
log tree code was added in 2008:

  Btrfs: Add a write ahead tree log to optimize synchronous operations
  (commit e02119d5a7b4396c5a872582fddc8bd6d305a70a)

Test cases for xfstests follow soon.

Signed-off-by: Filipe Manana 
Signed-off-by: Chris Mason 
Signed-off-by: Greg Kroah-Hartman

btrfs: fix leak of path in btrfs_find_item

2015-03-06T22:53:05+00:00

commit 381cf6587f8a8a8e981bc0c1aaaa8859b51dc756 upstream.

If btrfs_find_item is called with NULL path it allocates one locally but
does not free it. Affected paths are inserting an orphan item for a file
and for a subvol root.

Move the path allocation to the callers.

Fixes: 3f870c289900 ("btrfs: expand btrfs_find_item() to include find_orphan_item functionality")
Signed-off-by: David Sterba 
Signed-off-by: Greg Kroah-Hartman

btrfs: set proper message level for skinny metadata

2015-03-06T22:53:05+00:00

commit 5efa0490cc94aee06cd8d282683e22a8ce0a0026 upstream.

This has been confusing people for too long, the message is really just
informative.

Signed-off-by: David Sterba 
Signed-off-by: Chris Mason 
Signed-off-by: Greg Kroah-Hartman