In jbd2_get_transaction, a new transaction is initialized,
and set to the j_running_transaction. No need for a return
value, so remove it.

Also, adjust some comments to match the actual operation
of this function.
Signed-off-by: Liu Song <liu.song11@zte.com.cn>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

In jbd2_journal_commit_transaction(), if we are in abort mode,
we may flush the buffer without setting descriptor block checksum
by goto start_journal_io. Then fs is mounted,
jbd2_descriptor_block_csum_verify() failed.

[  271.379811] EXT4-fs (vdd): shut down requested (2)
[  271.381827] Aborting journal on device vdd-8.
[  271.597136] JBD2: Invalid checksum recovering block 22199 in log
[  271.598023] JBD2: recovery failed
[  271.598484] EXT4-fs (vdd): error loading journal

Fix this problem by keep setting descriptor block checksum if the
descriptor buffer is not NULL.

This checksum problem can be reproduced by xfstests generic/388.
Signed-off-by: luojiajun <luojiajun3@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

Ext4 may not free clusters correctly when punching holes in bigalloc
file systems under high load conditions.  If it's not possible to
extend and restart the journal in ext4_ext_rm_leaf() when preparing to
remove blocks from a punched region, a retry of the entire punch
operation is triggered in ext4_ext_remove_space().  This causes a
partial cluster to be set to the first cluster in the extent found to
the right of the punched region.  However, if the punch operation
prior to the retry had made enough progress to delete one or more
extents and a partial cluster candidate for freeing had already been
recorded, the retry would overwrite the partial cluster.  The loss of
this information makes it impossible to correctly free the original
partial cluster in all cases.

This bug can cause generic/476 to fail when run as part of
xfstests-bld's bigalloc and bigalloc_1k test cases.  The failure is
reported when e2fsck detects bad iblocks counts greater than expected
in units of whole clusters and also detects a number of negative block
bitmap differences equal to the iblocks discrepancy in cluster units.
Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

This is useful for moving journal thread into cgroup or
for tracing it with ftrace/perf/blktrace.

For now the only way is `pgrep jbd2/$DISK` but this is not reliable:
name may be longer than "comm" limit and any task could mock it.

Attribute shows pid in current pid-namespace or 0 if task is unreachable.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

All other configuration options for the ext* family of file systems use
"Ext%u" instead of "EXT%u".

Fixes: 6ba495e9 ("ext4: Add configurable run-time mballoc debugging")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Fix compile error below when using BUFFER_TRACE.

fs/ext4/inode.c: In function ‘ext4_expand_extra_isize’:
fs/ext4/inode.c:5979:19: error: request for member ‘bh’ in something not a structure or union
  BUFFER_TRACE(iloc.bh, "get_write_access");

Fixes: c03b45b8 ("ext4, project: expand inode extra size if possible")
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

The jh pointer may be used uninitialized in the two cases below and the
compiler complain about it when enabling JBUFFER_TRACE macro, fix them.

In file included from fs/jbd2/transaction.c:19:0:
fs/jbd2/transaction.c: In function ‘jbd2_journal_get_undo_access’:
./include/linux/jbd2.h:1637:38: warning: ‘jh’ is used uninitialized in this function [-Wuninitialized]
 #define JBUFFER_TRACE(jh, info) do { printk("%s: %d\n", __func__, jh->b_jcount);} while (0)
                                      ^
fs/jbd2/transaction.c:1219:23: note: ‘jh’ was declared here
  struct journal_head *jh;
                       ^
In file included from fs/jbd2/transaction.c:19:0:
fs/jbd2/transaction.c: In function ‘jbd2_journal_dirty_metadata’:
./include/linux/jbd2.h:1637:38: warning: ‘jh’ may be used uninitialized in this function [-Wmaybe-uninitialized]
 #define JBUFFER_TRACE(jh, info) do { printk("%s: %d\n", __func__, jh->b_jcount);} while (0)
                                      ^
fs/jbd2/transaction.c:1332:23: note: ‘jh’ was declared here
  struct journal_head *jh;
                       ^
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>

We can't pass error pointers to brelse().

Fixes: fb265c9c ("ext4: add ext4_sb_bread() to disambiguate ENOMEM cases")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

There is a plan to build the kernel with -Wimplicit-fallthrough and
these places in the code produced warnings (W=1). Fix them up.

This commit remove the following warnings:

  fs/ext4/indirect.c:1182:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
  fs/ext4/indirect.c:1188:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
  fs/ext4/indirect.c:1432:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
  fs/ext4/indirect.c:1440:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>

There is a plan to build the kernel with -Wimplicit-fallthrough and
these places in the code produced warnings (W=1). Fix them up.

This commit remove the following warnings:

  fs/ext4/hash.c:233:15: warning: this statement may fall through [-Wimplicit-fallthrough=]
  fs/ext4/hash.c:246:15: warning: this statement may fall through [-Wimplicit-fallthrough=]
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>

Don't update the superblock s_rev_level during mount if it isn't
actually necessary, only if superblock features are being set by
the kernel.  This was originally added for ext3 since it always
set the INCOMPAT_RECOVER and HAS_JOURNAL features during mount,
but this is not needed since no journal mode was added to ext4.

That will allow Geert to mount his 20-year-old ext2 rev 0.0 m68k
filesystem, as a testament of the backward compatibility of ext4.

Fixes: 0390131b ("ext4: Allow ext4 to run without a journal")
Signed-off-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

The functions jbd2_superblock_csum_verify() and
jbd2_superblock_csum_set() only get called from one location, so to
simplify things, fold them into their callers.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

The jbd2 superblock is lockless now, so there is probably a race
condition between writing it so disk and modifing contents of it, which
may lead to checksum error. The following race is the one case that we
have captured.

jbd2                                fsstress
jbd2_journal_commit_transaction
 jbd2_journal_update_sb_log_tail
  jbd2_write_superblock
   jbd2_superblock_csum_set         jbd2_journal_revoke
                                     jbd2_journal_set_features(revork)
                                     modify superblock
   submit_bh(checksum incorrect)

Fix this by locking the buffer head before modifing it.  We always
write the jbd2 superblock after we modify it, so this just means
calling the lock_buffer() a little earlier.

This checksum corruption problem can be reproduced by xfstests
generic/475.
Reported-by: zhangyi (F) <yi.zhang@huawei.com>
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

When computing maximum size of filesystem possible with given number of
group descriptor blocks, we forget to include s_first_data_block into
the number of blocks. Thus for filesystems with non-zero
s_first_data_block it can happen that computed maximum filesystem size
is actually lower than current filesystem size which confuses the code
and eventually leads to a BUG_ON in ext4_alloc_group_tables() hitting on
flex_gd->count == 0. The problem can be reproduced like:

truncate -s 100g /tmp/image
mkfs.ext4 -b 1024 -E resize=262144 /tmp/image 32768
mount -t ext4 -o loop /tmp/image /mnt
resize2fs /dev/loop0 262145
resize2fs /dev/loop0 300000

Fix the problem by properly including s_first_data_block into the
computed number of filesystem blocks.

Fixes: 1c6bd717 "ext4: convert file system to meta_bg if needed..."
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

A malicious/clueless root user can use EXT4_IOC_SWAP_BOOT to force a
corner casew which can lead to the file system getting corrupted.
There's no usefulness to allowing this, so just prohibit this case.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

The reason is that while swapping two inode, we swap the flags too.
Some flags such as EXT4_JOURNAL_DATA_FL can really confuse the things
since we're not resetting the address operations structure.  The
simplest way to keep things sane is to restrict the flags that can be
swapped.
Signed-off-by: yangerkun <yangerkun@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

While do swap between two inode, they swap i_data without update
quota information. Also, swap_inode_boot_loader can do "revert"
somtimes, so update the quota while all operations has been finished.
Signed-off-by: yangerkun <yangerkun@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

While do swap, we should make sure there has no new dirty page since we
should swap i_data between two inode:
1.We should lock i_mmap_sem with write to avoid new pagecache from mmap
read/write;
2.Change filemap_flush to filemap_write_and_wait and move them to the
space protected by inode lock to avoid new pagecache from buffer read/write.
Signed-off-by: yangerkun <yangerkun@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

Before really do swap between inode and boot inode, something need to
check to avoid invalid or not permitted operation, like does this inode
has inline data. But the condition check should be protected by inode
lock to avoid change while swapping. Also some other condition will not
change between swapping, but there has no problem to do this under inode
lock.
Signed-off-by: yangerkun <yangerkun@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

In mpage_add_bh_to_extent(), when accumulated extents length is greater
than MAX_WRITEPAGES_EXTENT_LEN or buffer head's b_stat is not equal, we
will not continue to search unmapped area for this page, but note this
page is locked, and will only be unlocked in mpage_release_unused_pages()
after ext4_io_submit, if io also is throttled by blk-throttle or similar
io qos, we will hold this page locked for a while, it's unnecessary.

I think the best fix is to refactor mpage_add_bh_to_extent() to let it
return some hints whether to unlock this page, but given that we will
improve dioread_nolock later, we can let it done later, so currently
the simple fix would just call mpage_release_unused_pages() before
ext4_io_submit().
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Now, we have already handle all cases of forgetting buffer in
jbd2_journal_forget(), the buffer should not be mapped to blockdevice
when reallocating it. So this patch remove all clean_bdev_aliases() and
clean_bdev_bh_alias() calls which were invoked by ext4 explicitly.
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

We do not unmap and clear dirty flag when forgetting a buffer without
journal or does not belongs to any transaction, so the invalid dirty
data may still be written to the disk later. It's fine if the
corresponding block is never used before the next mount, and it's also
fine that we invoke clean_bdev_aliases() related functions to unmap
the block device mapping when re-allocating such freed block as data
block. But this logic is somewhat fragile and risky that may lead to
data corruption if we forget to clean bdev aliases. So, It's better to
discard dirty data during forget time.

We have been already handled all the cases of forgetting journalled
buffer, this patch deal with the remaining two cases.

- buffer is not journalled yet,
- buffer is journalled but doesn't belongs to any transaction.

We invoke __bforget() instead of __brelese() when forgetting an
un-journalled buffer in jbd2_journal_forget(). After this patch we can
remove all clean_bdev_aliases() related calls in ext4.
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

Now, we capture a data corruption problem on ext4 while we're truncating
an extent index block. Imaging that if we are revoking a buffer which
has been journaled by the committing transaction, the buffer's jbddirty
flag will not be cleared in jbd2_journal_forget(), so the commit code
will set the buffer dirty flag again after refile the buffer.

fsx                               kjournald2
                                  jbd2_journal_commit_transaction
jbd2_journal_revoke                commit phase 1~5...
 jbd2_journal_forget
   belongs to older transaction    commit phase 6
   jbddirty not clear               __jbd2_journal_refile_buffer
                                     __jbd2_journal_unfile_buffer
                                      test_clear_buffer_jbddirty
                                       mark_buffer_dirty

Finally, if the freed extent index block was allocated again as data
block by some other files, it may corrupt the file data after writing
cached pages later, such as during unmount time. (In general,
clean_bdev_aliases() related helpers should be invoked after
re-allocation to prevent the above corruption, but unfortunately we
missed it when zeroout the head of extra extent blocks in
ext4_ext_handle_unwritten_extents()).

This patch mark buffer as freed and set j_next_transaction to the new
transaction when it already belongs to the committing transaction in
jbd2_journal_forget(), so that commit code knows it should clear dirty
bits when it is done with the buffer.

This problem can be reproduced by xfstests generic/455 easily with
seeds (3246 3247 3248 3249).
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: stable@vger.kernel.org

There is a function which clearly conveys the objective of checking
i_writecount. Additionally the usage in ext4_mb_initialize_context was
wrong, since a node would have wrongfully been reported as writable if
i_writecount had a negative value (MMAP_DENY_WRITE).
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

This issue was found when I tried to put checkpoint work in a separate thread,
the deadlock below happened:
         Thread1                                |   Thread2
__jbd2_log_wait_for_space                       |
jbd2_log_do_checkpoint (hold j_checkpoint_mutex)|
  if (jh->b_transaction != NULL)                |
    ...                                         |
    jbd2_log_start_commit(journal, tid);        |jbd2_update_log_tail
                                                |  will lock j_checkpoint_mutex,
                                                |  but will be blocked here.
                                                |
    jbd2_log_wait_commit(journal, tid);         |
    wait_event(journal->j_wait_done_commit,     |
     !tid_gt(tid, journal->j_commit_sequence)); |
     ...                                        |wake_up(j_wait_done_commit)
  }                                             |

then deadlock occurs, Thread1 will never be waken up.

To fix this issue, drop j_checkpoint_mutex in jbd2_log_do_checkpoint()
when we are going to wait for transaction commit.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

This reverts commit ad211f3e.

As Jan Kara pointed out, this change was unsafe since it means we lose
the call to sync_mapping_buffers() in the nojournal case.  The
original point of the commit was avoid taking the inode mutex (since
it causes a lockdep warning in generic/113); but we need the mutex in
order to call sync_mapping_buffers().

The real fix to this problem was discussed here:

https://lore.kernel.org/lkml/20181025150540.259281-4-bvanassche@acm.org

The proposed patch was to fix a syzbot complaint, but the problem can
also demonstrated via "kvm-xfstests -c nojournal generic/113".
Multiple solutions were discused in the e-mail thread, but none have
landed in the kernel as of this writing.  Anyway, commit
ad211f3e is absolutely the wrong way to suppress the lockdep, so
revert it.

Fixes: ad211f3e ("ext4: use ext4_write_inode() when fsyncing w/o a journal")
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reported: Jan Kara <jack@suse.cz>

Pull pstore fixes from Kees Cook:

 - Fix console ramoops to show the previous boot logs (Sai Prakash
   Ranjan)

 - Avoid allocation and leak of platform data

* tag 'pstore-v5.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  pstore/ram: Avoid allocation and leak of platform data
  pstore/ram: Fix console ramoops to show the previous boot logs

Pull gcc-plugins fixes from Kees Cook:
 "Fix ARM per-task stack protector plugin under GCC 9 (Ard Biesheuvel)"

* tag 'gcc-plugins-v5.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  gcc-plugins: arm_ssp_per_task_plugin: fix for GCC 9+
  gcc-plugins: arm_ssp_per_task_plugin: sign extend the SP mask

Pull networking fixes from David Miller:

 1) Fix endless loop in nf_tables, from Phil Sutter.

 2) Fix cross namespace ip6_gre tunnel hash list corruption, from
    Olivier Matz.

 3) Don't be too strict in phy_start_aneg() otherwise we might not allow
    restarting auto negotiation. From Heiner Kallweit.

 4) Fix various KMSAN uninitialized value cases in tipc, from Ying Xue.

 5) Memory leak in act_tunnel_key, from Davide Caratti.

 6) Handle chip errata of mv88e6390 PHY, from Andrew Lunn.

 7) Remove linear SKB assumption in fou/fou6, from Eric Dumazet.

 8) Missing udplite rehash callbacks, from Alexey Kodanev.

 9) Log dirty pages properly in vhost, from Jason Wang.

10) Use consume_skb() in neigh_probe() as this is a normal free not a
    drop, from Yang Wei. Likewise in macvlan_process_broadcast().

11) Missing device_del() in mdiobus_register() error paths, from Thomas
    Petazzoni.

12) Fix checksum handling of short packets in mlx5, from Cong Wang.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (96 commits)
  bpf: in __bpf_redirect_no_mac pull mac only if present
  virtio_net: bulk free tx skbs
  net: phy: phy driver features are mandatory
  isdn: avm: Fix string plus integer warning from Clang
  net/mlx5e: Fix cb_ident duplicate in indirect block register
  net/mlx5e: Fix wrong (zero) TX drop counter indication for representor
  net/mlx5e: Fix wrong error code return on FEC query failure
  net/mlx5e: Force CHECKSUM_UNNECESSARY for short ethernet frames
  tools: bpftool: Cleanup license mess
  bpf: fix inner map masking to prevent oob under speculation
  bpf: pull in pkt_sched.h header for tooling to fix bpftool build
  selftests: forwarding: Add a test case for externally learned FDB entries
  selftests: mlxsw: Test FDB offload indication
  mlxsw: spectrum_switchdev: Do not treat static FDB entries as sticky
  net: bridge: Mark FDB entries that were added by user as such
  mlxsw: spectrum_fid: Update dummy FID index
  mlxsw: pci: Return error on PCI reset timeout
  mlxsw: pci: Increase PCI SW reset timeout
  mlxsw: pci: Ring CQ's doorbell before RDQ's
  MAINTAINERS: update email addresses of liquidio driver maintainers
  ...

Yue Hu noticed that when parsing device tree the allocated platform data
was never freed. Since it's not used beyond the function scope, this
switches to using a stack variable instead.
Reported-by: Yue Hu <huyue2@yulong.com>
Fixes: 35da6094 ("pstore/ram: add Device Tree bindings")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>

GCC 9 reworks the way the references to the stack canary are
emitted, to prevent the value from being spilled to the stack
before the final comparison in the epilogue, defeating the
purpose, given that the spill slot is under control of the
attacker that we are protecting ourselves from.

Since our canary value address is obtained without accessing
memory (as opposed to pre-v7 code that will obtain it from a
literal pool), it is unlikely (although not guaranteed) that
the compiler will spill the canary value in the same way, so
let's just disable this improvement when building with GCC9+.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Kees Cook <keescook@chromium.org>

The ARM per-task stack protector GCC plugin hits an assert in
the compiler in some case, due to the fact the the SP mask
expression is not sign-extended as it should be. So fix that.
Suggested-by: Kugan Vivekanandarajah <kugan.vivekanandarajah@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Kees Cook <keescook@chromium.org>

Pull virtio/vhost fixes and cleanups from Michael Tsirkin:
 "Fixes and cleanups all over the place"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  vhost/scsi: Use copy_to_iter() to send control queue response
  vhost: return EINVAL if iovecs size does not match the message size
  virtio-balloon: tweak config_changed implementation
  virtio: don't allocate vqs when names[i] = NULL
  virtio_pci: use queue idx instead of array idx to set up the vq
  virtio: document virtio_config_ops restrictions
  virtio: fix virtio_config_ops description

Pull btrfs fixes from David Sterba:
 "A handful of fixes (some of them in testing for a long time):

   - fix some test failures regarding cleanup after transaction abort

   - revert of a patch that could cause a deadlock

   - delayed iput fixes, that can help in ENOSPC situation when there's
     low space and a lot data to write"

* tag 'for-5.0-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: wakeup cleaner thread when adding delayed iput
  btrfs: run delayed iputs before committing
  btrfs: wait on ordered extents on abort cleanup
  btrfs: handle delayed ref head accounting cleanup in abort
  Revert "btrfs: balance dirty metadata pages in btrfs_finish_ordered_io"

Merge tags 'compiler-attributes-for-linus-v5.0-rc3' and 'clang-format-for-linus-v5.0-rc3' of git://github.com/ojeda/linux

Pull misc clang fixes from Miguel Ojeda:

  - A fix for OPTIMIZER_HIDE_VAR from Michael S Tsirkin

  - Update clang-format with the latest for_each macro list from Jason
    Gunthorpe

* tag 'compiler-attributes-for-linus-v5.0-rc3' of git://github.com/ojeda/linux:
  include/linux/compiler*.h: fix OPTIMIZER_HIDE_VAR

* tag 'clang-format-for-linus-v5.0-rc3' of git://github.com/ojeda/linux:
  clang-format: Update .clang-format with the latest for_each macro list

If an input number x for int_sqrt64() has the highest bit set, then
fls64(x) is 64.  (1UL << 64) is an overflow and breaks the algorithm.

Subtracting 1 is a better guess for the initial value of m anyway and
that's what also done in int_sqrt() implicitly [*].

[*] Note how int_sqrt() uses __fls() with two underscores, which already
    returns the proper raw bit number.

    In contrast, int_sqrt64() used fls64(), and that returns bit numbers
    illogically starting at 1, because of error handling for the "no
    bits set" case. Will points out that he bug probably is due to a
    copy-and-paste error from the regular int_sqrt() case.
Signed-off-by: Florian La Roche <Florian.LaRoche@googlemail.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 594cc251 ("make 'user_access_begin()' do 'access_ok()'")
makes the access_ok() check part of the user_access_begin() preceding a
series of 'unsafe' accesses.  This has the desirable effect of ensuring
that all 'unsafe' accesses have been range-checked, without having to
pick through all of the callsites to verify whether the appropriate
checking has been made.

However, the consolidated range check does not inhibit speculation, so
it is still up to the caller to ensure that they are not susceptible to
any speculative side-channel attacks for user addresses that ultimately
fail the access_ok() check.

This is an oversight, so use __uaccess_begin_nospec() to ensure that
speculation is inhibited until the access_ok() check has passed.
Reported-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull arm64 fixes from Will Deacon:
 "Three arm64 fixes for -rc3.

  We've plugged a couple of nasty issues involving KASLR-enabled
  kernels, and removed a redundant #define that was introduced as part
  of the KHWASAN fixes from akpm at -rc2.

   - Fix broken kpti page-table rewrite in bizarre KASLR configuration

   - Fix module loading with KASLR

   - Remove redundant definition of ARCH_SLAB_MINALIGN"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  kasan, arm64: remove redundant ARCH_SLAB_MINALIGN define
  arm64: kaslr: ensure randomized quantities are clean to the PoC
  arm64: kpti: Update arm64_kernel_use_ng_mappings() when forced on

Daniel Borkmann says:

====================
pull-request: bpf 2019-01-20

The following pull-request contains BPF updates for your *net* tree.

The main changes are:

1) Fix a out-of-bounds access in __bpf_redirect_no_mac, from Willem.

2) Fix bpf_setsockopt to reset sock dst on SO_MARK changes, from Peter.

3) Fix map in map masking to prevent out-of-bounds access under
   speculative execution, from Daniel.

4) Fix bpf_setsockopt's SO_MAX_PACING_RATE to support TCP internal
   pacing, from Yuchung.

5) Fix json writer license in bpftool, from Thomas.

6) Fix AF_XDP to check if an actually queue exists during umem
   setup, from Krzysztof.

7) Several fixes to BPF stackmap's build id handling. Another fix
   for bpftool build to account for libbfd variations wrt linking
   requirements, from Stanislav.

8) Fix BPF samples build with clang by working around missing asm
   goto, from Yonghong.

9) Fix libbpf to retry program load on signal interrupt, from Lorenz.

10) Various minor compile warning fixes in BPF code, from Mathieu.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>