<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux/include/uapi, branch v5.5-rc2</title>
<subtitle>Mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/
</subtitle>
<id>https://www.git.shady.money/linux/atom?h=v5.5-rc2</id>
<link rel='self' href='https://www.git.shady.money/linux/atom?h=v5.5-rc2'/>
<link rel='alternate' type='text/html' href='https://www.git.shady.money/linux/'/>
<updated>2019-12-13T22:24:54Z</updated>
<entry>
<title>Merge tag 'io_uring-5.5-20191212' of git://git.kernel.dk/linux-block</title>
<updated>2019-12-13T22:24:54Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2019-12-13T22:24:54Z</published>
<link rel='alternate' type='text/html' href='https://www.git.shady.money/linux/commit/?id=5bd831a469e0c8368fe02b21157ea5c731f84967'/>
<id>urn:sha1:5bd831a469e0c8368fe02b21157ea5c731f84967</id>
<content type='text'>
Pull io_uring fixes from Jens Axboe:

 - A tweak to IOSQE_IO_LINK (also marked for stable) to allow links that
   don't sever if the result is &lt; 0.

   This is mostly for linked timeouts, where if we ask for a pure
   timeout we always get -ETIME. This makes links useless for that case,
   hence allow a case where it works.

 - Five minor optimizations to fix and improve cases that regressed
   since v5.4.

 - An SQTHREAD locking fix.

 - A sendmsg/recvmsg iov assignment fix.

 - Net fix where read_iter/write_iter don't honor IOCB_NOWAIT, and
   subsequently ensuring that works for io_uring.

 - Fix a case where for an invalid opcode we might return -EBADF instead
   of -EINVAL, if the -&gt;fd of that sqe was set to an invalid fd value.

* tag 'io_uring-5.5-20191212' of git://git.kernel.dk/linux-block:
  io_uring: ensure we return -EINVAL on unknown opcode
  io_uring: add sockets to list of files that support non-blocking issue
  net: make socket read/write_iter() honor IOCB_NOWAIT
  io_uring: only hash regular files for async work execution
  io_uring: run next sqe inline if possible
  io_uring: don't dynamically allocate poll data
  io_uring: deferred send/recvmsg should assign iov
  io_uring: sqthread should grab ctx-&gt;uring_lock for submissions
  io-wq: briefly spin for new work after finishing work
  io-wq: remove worker-&gt;wait waitqueue
  io_uring: allow unbreakable links
</content>
</entry>
<entry>
<title>io_uring: ensure we return -EINVAL on unknown opcode</title>
<updated>2019-12-11T23:02:32Z</updated>
<author>
<name>Jens Axboe</name>
<email>axboe@kernel.dk</email>
</author>
<published>2019-12-11T22:55:43Z</published>
<link rel='alternate' type='text/html' href='https://www.git.shady.money/linux/commit/?id=9e3aa61ae3e01ce1ce6361a41ef725e1f4d1d2bf'/>
<id>urn:sha1:9e3aa61ae3e01ce1ce6361a41ef725e1f4d1d2bf</id>
<content type='text'>
If we submit an unknown opcode and have fd == -1, io_op_needs_file()
will return true as we default to needing a file. Then when we go and
assign the file, we find the 'fd' invalid and return -EBADF. We really
should be returning -EINVAL for that case, as we normally do for
unsupported opcodes.

Change io_op_needs_file() to have the following return values:

0   - does not need a file
1   - does need a file
&lt; 0 - error value

and use this to pass back the right value for this invalid case.

Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</content>
</entry>
<entry>
<title>io_uring: allow unbreakable links</title>
<updated>2019-12-10T23:33:06Z</updated>
<author>
<name>Jens Axboe</name>
<email>axboe@kernel.dk</email>
</author>
<published>2019-12-08T03:59:47Z</published>
<link rel='alternate' type='text/html' href='https://www.git.shady.money/linux/commit/?id=4e88d6e7793f2f445f43bd608828541d7f43b608'/>
<id>urn:sha1:4e88d6e7793f2f445f43bd608828541d7f43b608</id>
<content type='text'>
Some commands will invariably end in a failure in the sense that the
completion result will be less than zero. One such example is timeouts
that don't have a completion count set, they will always complete with
-ETIME unless cancelled.

For linked commands, we sever links and fail the rest of the chain if
the result is less than zero. Since we have commands where we know that
will happen, add IOSQE_IO_HARDLINK as a stronger link that doesn't sever
regardless of the completion result. Note that the link will still sever
if we fail submitting the parent request, hard links are only resilient
in the presence of completion results for requests that did submit
correctly.

Cc: stable@vger.kernel.org # v5.4
Reviewed-by: Pavel Begunkov &lt;asml.silence@gmail.com&gt;
Reported-by: 李通洲 &lt;carter.li@eoitek.com&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</content>
</entry>
<entry>
<title>Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input</title>
<updated>2019-12-08T02:33:01Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2019-12-08T02:33:01Z</published>
<link rel='alternate' type='text/html' href='https://www.git.shady.money/linux/commit/?id=737214515d7965485c52bc5f869e57a6976cf216'/>
<id>urn:sha1:737214515d7965485c52bc5f869e57a6976cf216</id>
<content type='text'>
Pull more input updates from Dmitry Torokhov:

 - fixups for Synaptics RMI4 driver

 - a quirk for Goodinx touchscreen on Teclast tablet

 - a new keycode definition for activating privacy screen feature found
   on a few "enterprise" laptops

 - updates to snvs_pwrkey driver

 - polling uinput device for writing (which is always allowed) now works

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: synaptics-rmi4 - don't increment rmiaddr for SMBus transfers
  Input: synaptics-rmi4 - re-enable IRQs in f34v7_do_reflash
  Input: goodix - add upside-down quirk for Teclast X89 tablet
  Input: add privacy screen toggle keycode
  Input: uinput - fix returning EPOLLOUT from uinput_poll
  Input: snvs_pwrkey - remove gratuitous NULL initializers
  Input: snvs_pwrkey - send key events for i.MX6 S, DL and Q
</content>
</entry>
<entry>
<title>Merge tag 'for-linus-20191205' of git://git.kernel.dk/linux-block</title>
<updated>2019-12-06T18:08:59Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2019-12-06T18:08:59Z</published>
<link rel='alternate' type='text/html' href='https://www.git.shady.money/linux/commit/?id=9feb1af97e7366b512ecb9e4dd61d3252074cda3'/>
<id>urn:sha1:9feb1af97e7366b512ecb9e4dd61d3252074cda3</id>
<content type='text'>
Pull more block and io_uring updates from Jens Axboe:
 "I wasn't expecting this to be so big, and if I was, I would have used
  separate branches for this. Going forward I'll be doing separate
  branches for the current tree, just like for the next kernel version
  tree. In any case, this contains:

   - Series from Christoph that fixes an inherent race condition with
     zoned devices and revalidation.

   - null_blk zone size fix (Damien)

   - Fix for a regression in this merge window that caused busy spins by
     sending empty disk uevents (Eric)

   - Fix for a regression in this merge window for bfq stats (Hou)

   - Fix for io_uring creds allocation failure handling (me)

   - io_uring -ERESTARTSYS send/recvmsg fix (me)

   - Series that fixes the need for applications to retain state across
     async request punts for io_uring. This one is a bit larger than I
     would have hoped, but I think it's important we get this fixed for
     5.5.

   - connect(2) improvement for io_uring, handling EINPROGRESS instead
     of having applications needing to poll for it (me)

   - Have io_uring use a hash for poll requests instead of an rbtree.
     This turned out to work much better in practice, so I think we
     should make the switch now. For some workloads, even with a fair
     amount of cancellations, the insertion sort is just too expensive.
     (me)

   - Various little io_uring fixes (me, Jackie, Pavel, LimingWu)

   - Fix for brd unaligned IO, and a warning for the future (Ming)

   - Fix for a bio integrity data leak (Justin)

   - bvec_iter_advance() improvement (Pavel)

   - Xen blkback page unmap fix (SeongJae)

  The major items in here are all well tested, and on the liburing side
  we continue to add regression and feature test cases. We're up to 50
  topic cases now, each with anywhere from 1 to more than 10 cases in
  each"

* tag 'for-linus-20191205' of git://git.kernel.dk/linux-block: (33 commits)
  block: fix memleak of bio integrity data
  io_uring: fix a typo in a comment
  bfq-iosched: Ensure bio-&gt;bi_blkg is valid before using it
  io_uring: hook all linked requests via link_list
  io_uring: fix error handling in io_queue_link_head
  io_uring: use hash table for poll command lookups
  io-wq: clear node-&gt;next on list deletion
  io_uring: ensure deferred timeouts copy necessary data
  io_uring: allow IO_SQE_* flags on IORING_OP_TIMEOUT
  null_blk: remove unused variable warning on !CONFIG_BLK_DEV_ZONED
  brd: warn on un-aligned buffer
  brd: remove max_hw_sectors queue limit
  xen/blkback: Avoid unmapping unmapped grant pages
  io_uring: handle connect -EINPROGRESS like -EAGAIN
  block: set the zone size in blk_revalidate_disk_zones atomically
  block: don't handle bio based drivers in blk_revalidate_disk_zones
  block: allocate the zone bitmaps lazily
  block: replace seq_zones_bitmap with conv_zones_bitmap
  block: simplify blkdev_nr_zones
  block: remove the empty line at the end of blk-zoned.c
  ...
</content>
</entry>
<entry>
<title>Merge branch 'akpm' (patches from Andrew)</title>
<updated>2019-12-05T17:46:26Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2019-12-05T17:46:26Z</published>
<link rel='alternate' type='text/html' href='https://www.git.shady.money/linux/commit/?id=5ecc9d15f73b82c748526350d5602c94fdd65cac'/>
<id>urn:sha1:5ecc9d15f73b82c748526350d5602c94fdd65cac</id>
<content type='text'>
Merge more updates from Andrew Morton:
 "Most of the rest of MM and various other things. Some Kconfig rework
  still awaits merges of dependent trees from linux-next.

  Subsystems affected by this patch series: mm/hotfixes, mm/memcg,
  mm/vmstat, mm/thp, procfs, sysctl, misc, notifiers, core-kernel,
  bitops, lib, checkpatch, epoll, binfmt, init, rapidio, uaccess, kcov,
  ubsan, ipc, bitmap, mm/pagemap"

* akpm: (86 commits)
  mm: remove __ARCH_HAS_4LEVEL_HACK and include/asm-generic/4level-fixup.h
  um: add support for folded p4d page tables
  um: remove unused pxx_offset_proc() and addr_pte() functions
  sparc32: use pgtable-nopud instead of 4level-fixup
  parisc/hugetlb: use pgtable-nopXd instead of 4level-fixup
  parisc: use pgtable-nopXd instead of 4level-fixup
  nds32: use pgtable-nopmd instead of 4level-fixup
  microblaze: use pgtable-nopmd instead of 4level-fixup
  m68k: mm: use pgtable-nopXd instead of 4level-fixup
  m68k: nommu: use pgtable-nopud instead of 4level-fixup
  c6x: use pgtable-nopud instead of 4level-fixup
  arm: nommu: use pgtable-nopud instead of 4level-fixup
  alpha: use pgtable-nopud instead of 4level-fixup
  gpio: pca953x: tighten up indentation
  gpio: pca953x: convert to use bitmap API
  gpio: pca953x: use input from regs structure in pca953x_irq_pending()
  gpio: pca953x: remove redundant variable and check in IRQ handler
  lib/bitmap: introduce bitmap_replace() helper
  lib/test_bitmap: fix comment about this file
  lib/test_bitmap: move exp1 and exp2 upper for others to use
  ...
</content>
</entry>
<entry>
<title>arch: sembuf.h: make uapi asm/sembuf.h self-contained</title>
<updated>2019-12-05T03:44:14Z</updated>
<author>
<name>Masahiro Yamada</name>
<email>yamada.masahiro@socionext.com</email>
</author>
<published>2019-12-05T00:53:03Z</published>
<link rel='alternate' type='text/html' href='https://www.git.shady.money/linux/commit/?id=0fb9dc28679a627f84974165c8011e0630529ece'/>
<id>urn:sha1:0fb9dc28679a627f84974165c8011e0630529ece</id>
<content type='text'>
Userspace cannot compile &lt;asm/sembuf.h&gt; due to some missing type
definitions.  For example, building it for x86 fails as follows:

    CC      usr/include/asm/sembuf.h.s
  In file included from &lt;command-line&gt;:32:0:
  usr/include/asm/sembuf.h:17:20: error: field `sem_perm' has incomplete type
    struct ipc64_perm sem_perm; /* permissions .. see ipc.h */
                      ^~~~~~~~
  usr/include/asm/sembuf.h:24:2: error: unknown type name `__kernel_time_t'
    __kernel_time_t sem_otime; /* last semop time */
    ^~~~~~~~~~~~~~~
  usr/include/asm/sembuf.h:25:2: error: unknown type name `__kernel_ulong_t'
    __kernel_ulong_t __unused1;
    ^~~~~~~~~~~~~~~~
  usr/include/asm/sembuf.h:26:2: error: unknown type name `__kernel_time_t'
    __kernel_time_t sem_ctime; /* last change time */
    ^~~~~~~~~~~~~~~
  usr/include/asm/sembuf.h:27:2: error: unknown type name `__kernel_ulong_t'
    __kernel_ulong_t __unused2;
    ^~~~~~~~~~~~~~~~
  usr/include/asm/sembuf.h:29:2: error: unknown type name `__kernel_ulong_t'
    __kernel_ulong_t sem_nsems; /* no. of semaphores in array */
    ^~~~~~~~~~~~~~~~
  usr/include/asm/sembuf.h:30:2: error: unknown type name `__kernel_ulong_t'
    __kernel_ulong_t __unused3;
    ^~~~~~~~~~~~~~~~
  usr/include/asm/sembuf.h:31:2: error: unknown type name `__kernel_ulong_t'
    __kernel_ulong_t __unused4;
    ^~~~~~~~~~~~~~~~

It is just a matter of missing include directive.

Include &lt;asm/ipcbuf.h&gt; to make it self-contained, and add it to
the compile-test coverage.

Link: http://lkml.kernel.org/r/20191030063855.9989-3-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
Cc: Arnd Bergmann &lt;arnd@arndb.de&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>arch: msgbuf.h: make uapi asm/msgbuf.h self-contained</title>
<updated>2019-12-05T03:44:14Z</updated>
<author>
<name>Masahiro Yamada</name>
<email>yamada.masahiro@socionext.com</email>
</author>
<published>2019-12-05T00:53:00Z</published>
<link rel='alternate' type='text/html' href='https://www.git.shady.money/linux/commit/?id=9ef0e004181956e158fb7ceb9b43810a193f80cd'/>
<id>urn:sha1:9ef0e004181956e158fb7ceb9b43810a193f80cd</id>
<content type='text'>
Userspace cannot compile &lt;asm/msgbuf.h&gt; due to some missing type
definitions.  For example, building it for x86 fails as follows:

    CC      usr/include/asm/msgbuf.h.s
  In file included from usr/include/asm/msgbuf.h:6:0,
                   from &lt;command-line&gt;:32:
  usr/include/asm-generic/msgbuf.h:25:20: error: field `msg_perm' has incomplete type
    struct ipc64_perm msg_perm;
                      ^~~~~~~~
  usr/include/asm-generic/msgbuf.h:27:2: error: unknown type name `__kernel_time_t'
    __kernel_time_t msg_stime; /* last msgsnd time */
    ^~~~~~~~~~~~~~~
  usr/include/asm-generic/msgbuf.h:28:2: error: unknown type name `__kernel_time_t'
    __kernel_time_t msg_rtime; /* last msgrcv time */
    ^~~~~~~~~~~~~~~
  usr/include/asm-generic/msgbuf.h:29:2: error: unknown type name `__kernel_time_t'
    __kernel_time_t msg_ctime; /* last change time */
    ^~~~~~~~~~~~~~~
  usr/include/asm-generic/msgbuf.h:41:2: error: unknown type name `__kernel_pid_t'
    __kernel_pid_t msg_lspid; /* pid of last msgsnd */
    ^~~~~~~~~~~~~~
  usr/include/asm-generic/msgbuf.h:42:2: error: unknown type name `__kernel_pid_t'
    __kernel_pid_t msg_lrpid; /* last receive pid */
    ^~~~~~~~~~~~~~

It is just a matter of missing include directive.

Include &lt;asm/ipcbuf.h&gt; to make it self-contained, and add it to
the compile-test coverage.

Link: http://lkml.kernel.org/r/20191030063855.9989-2-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
Cc: Arnd Bergmann &lt;arnd@arndb.de&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>arch: ipcbuf.h: make uapi asm/ipcbuf.h self-contained</title>
<updated>2019-12-05T03:44:14Z</updated>
<author>
<name>Masahiro Yamada</name>
<email>yamada.masahiro@socionext.com</email>
</author>
<published>2019-12-05T00:52:57Z</published>
<link rel='alternate' type='text/html' href='https://www.git.shady.money/linux/commit/?id=5b009673594d569674a9e0e60109f6a1723075b0'/>
<id>urn:sha1:5b009673594d569674a9e0e60109f6a1723075b0</id>
<content type='text'>
Userspace cannot compile &lt;asm/ipcbuf.h&gt; due to some missing type
definitions.  For example, building it for x86 fails as follows:

    CC      usr/include/asm/ipcbuf.h.s
  In file included from usr/include/asm/ipcbuf.h:1:0,
                   from &lt;command-line&gt;:32:
  usr/include/asm-generic/ipcbuf.h:21:2: error: unknown type name `__kernel_key_t'
    __kernel_key_t  key;
    ^~~~~~~~~~~~~~
  usr/include/asm-generic/ipcbuf.h:22:2: error: unknown type name `__kernel_uid32_t'
    __kernel_uid32_t uid;
    ^~~~~~~~~~~~~~~~
  usr/include/asm-generic/ipcbuf.h:23:2: error: unknown type name `__kernel_gid32_t'
    __kernel_gid32_t gid;
    ^~~~~~~~~~~~~~~~
  usr/include/asm-generic/ipcbuf.h:24:2: error: unknown type name `__kernel_uid32_t'
    __kernel_uid32_t cuid;
    ^~~~~~~~~~~~~~~~
  usr/include/asm-generic/ipcbuf.h:25:2: error: unknown type name `__kernel_gid32_t'
    __kernel_gid32_t cgid;
    ^~~~~~~~~~~~~~~~
  usr/include/asm-generic/ipcbuf.h:26:2: error: unknown type name `__kernel_mode_t'
    __kernel_mode_t  mode;
    ^~~~~~~~~~~~~~~
  usr/include/asm-generic/ipcbuf.h:28:35: error: `__kernel_mode_t' undeclared here (not in a function)
    unsigned char  __pad1[4 - sizeof(__kernel_mode_t)];
                                     ^~~~~~~~~~~~~~~
  usr/include/asm-generic/ipcbuf.h:31:2: error: unknown type name `__kernel_ulong_t'
    __kernel_ulong_t __unused1;
    ^~~~~~~~~~~~~~~~
  usr/include/asm-generic/ipcbuf.h:32:2: error: unknown type name `__kernel_ulong_t'
    __kernel_ulong_t __unused2;
    ^~~~~~~~~~~~~~~~

It is just a matter of missing include directive.

Include &lt;linux/posix_types.h&gt; to make it self-contained, and add it to
the compile-test coverage.

Link: http://lkml.kernel.org/r/20191030063855.9989-1-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
Cc: Arnd Bergmann &lt;arnd@arndb.de&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>kcov: remote coverage support</title>
<updated>2019-12-05T03:44:14Z</updated>
<author>
<name>Andrey Konovalov</name>
<email>andreyknvl@google.com</email>
</author>
<published>2019-12-05T00:52:43Z</published>
<link rel='alternate' type='text/html' href='https://www.git.shady.money/linux/commit/?id=eec028c9386ed1a692aa01a85b55952202b41619'/>
<id>urn:sha1:eec028c9386ed1a692aa01a85b55952202b41619</id>
<content type='text'>
Patch series " kcov: collect coverage from usb and vhost", v3.

This patchset extends kcov to allow collecting coverage from backgound
kernel threads.  This extension requires custom annotations for each of
the places where coverage collection is desired.  This patchset
implements this for hub events in the USB subsystem and for vhost
workers.  See the first patch description for details about the kcov
extension.  The other two patches apply this kcov extension to USB and
vhost.

Examples of other subsystems that might potentially benefit from this
when custom annotations are added (the list is based on
process_one_work() callers for bugs recently reported by syzbot):

1. fs: writeback wb_workfn() worker,
2. net: addrconf_dad_work()/addrconf_verify_work() workers,
3. net: neigh_periodic_work() worker,
4. net/p9: p9_write_work()/p9_read_work() workers,
5. block: blk_mq_run_work_fn() worker.

These patches have been used to enable coverage-guided USB fuzzing with
syzkaller for the last few years, see the details here:

  https://github.com/google/syzkaller/blob/master/docs/linux/external_fuzzing_usb.md

This patchset has been pushed to the public Linux kernel Gerrit
instance:

  https://linux-review.googlesource.com/c/linux/kernel/git/torvalds/linux/+/1524

This patch (of 3):

Add background thread coverage collection ability to kcov.

With KCOV_ENABLE coverage is collected only for syscalls that are issued
from the current process.  With KCOV_REMOTE_ENABLE it's possible to
collect coverage for arbitrary parts of the kernel code, provided that
those parts are annotated with kcov_remote_start()/kcov_remote_stop().

This allows to collect coverage from two types of kernel background
threads: the global ones, that are spawned during kernel boot in a
limited number of instances (e.g.  one USB hub_event() worker thread is
spawned per USB HCD); and the local ones, that are spawned when a user
interacts with some kernel interface (e.g.  vhost workers).

To enable collecting coverage from a global background thread, a unique
global handle must be assigned and passed to the corresponding
kcov_remote_start() call.  Then a userspace process can pass a list of
such handles to the KCOV_REMOTE_ENABLE ioctl in the handles array field
of the kcov_remote_arg struct.  This will attach the used kcov device to
the code sections, that are referenced by those handles.

Since there might be many local background threads spawned from
different userspace processes, we can't use a single global handle per
annotation.  Instead, the userspace process passes a non-zero handle
through the common_handle field of the kcov_remote_arg struct.  This
common handle gets saved to the kcov_handle field in the current
task_struct and needs to be passed to the newly spawned threads via
custom annotations.  Those threads should in turn be annotated with
kcov_remote_start()/kcov_remote_stop().

Internally kcov stores handles as u64 integers.  The top byte of a
handle is used to denote the id of a subsystem that this handle belongs
to, and the lower 4 bytes are used to denote the id of a thread instance
within that subsystem.  A reserved value 0 is used as a subsystem id for
common handles as they don't belong to a particular subsystem.  The
bytes 4-7 are currently reserved and must be zero.  In the future the
number of bytes used for the subsystem or handle ids might be increased.

When a particular userspace process collects coverage by via a common
handle, kcov will collect coverage for each code section that is
annotated to use the common handle obtained as kcov_handle from the
current task_struct.  However non common handles allow to collect
coverage selectively from different subsystems.

Link: http://lkml.kernel.org/r/e90e315426a384207edbec1d6aa89e43008e4caf.1572366574.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov &lt;andreyknvl@google.com&gt;
Cc: Dmitry Vyukov &lt;dvyukov@google.com&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Cc: "Michael S. Tsirkin" &lt;mst@redhat.com&gt;
Cc: Jason Wang &lt;jasowang@redhat.com&gt;
Cc: Arnd Bergmann &lt;arnd@arndb.de&gt;
Cc: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Cc: David Windsor &lt;dwindsor@gmail.com&gt;
Cc: Elena Reshetova &lt;elena.reshetova@intel.com&gt;
Cc: Anders Roxell &lt;anders.roxell@linaro.org&gt;
Cc: Alexander Potapenko &lt;glider@google.com&gt;
Cc: Marco Elver &lt;elver@google.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
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