linux.git/lib, branch v5.0-rc5

lib/test_kmod.c: potential double free in error handling

2019-02-01T23:46:23+00:00

There is a copy and paste bug so we set "config->test_driver" to NULL
twice instead of setting "config->test_fs".  Smatch complains that it
leads to a double free:

  lib/test_kmod.c:840 __kmod_config_init() warn: 'config->test_fs' double freed

Link: http://lkml.kernel.org/r/20190121140011.GA14283@kadam
Fixes: d9c6a72d6fa2 ("kmod: add test driver to stress test the module loader")
Signed-off-by: Dan Carpenter 
Acked-by: Luis Chamberlain 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge tag 'xarray-5.0-rc3' of git://git.infradead.org/users/willy/linux-dax

2019-01-22T04:08:30+00:00

Pull XArray fixes from Matthew Wilcox:
 "Fix some oversights in the XArray porcelain API:

   - support for m68k's two-byte aligned pointers

   - reserving entries using xa_insert()

   - missing xa_insert_bh() and xa_insert_irq() functions

   - simplify using xa_for_each()

   - use lockdep correctly

   - a few other minor fixes and improvements"

* tag 'xarray-5.0-rc3' of git://git.infradead.org/users/willy/linux-dax:
  XArray: Fix an arithmetic error in xa_is_err
  XArray tests: Check mark 2 gets squashed
  XArray: Fix typo in comment
  XArray: Honour reserved entries in xa_insert
  XArray: Permit storing 2-byte-aligned pointers
  XArray: Change xa_for_each iterator
  XArray: Turn xa_init_flags into a static inline
  XArray tests: Add RCU locking

fix int_sqrt64() for very large numbers

2019-01-20T18:20:18+00:00

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 
Acked-by: Will Deacon 
Signed-off-by: Linus Torvalds

sbitmap: Protect swap_lock from hardirq

2019-01-15T04:29:57+00:00

Because we may call blk_mq_get_driver_tag() directly from
blk_mq_dispatch_rq_list() without holding any lock, then HARDIRQ may
come and the above DEADLOCK is triggered.

Commit ab53dcfb3e7b ("sbitmap: Protect swap_lock from hardirq") tries to
fix this issue by using 'spin_lock_bh', which isn't enough because we
complete request from hardirq context direclty in case of multiqueue.

Cc: Clark Williams 
Fixes: ab53dcfb3e7b ("sbitmap: Protect swap_lock from hardirq")
Cc: Jens Axboe 
Cc: Ming Lei 
Cc: Guenter Roeck 
Cc: Steven Rostedt (VMware) 
Signed-off-by: Ming Lei 
Signed-off-by: Linus Torvalds

XArray tests: Check mark 2 gets squashed

2019-01-14T19:50:34+00:00

We do not currently check that the loop in xas_squash_marks() doesn't have
an off-by-one error in it.  It didn't, but a patch which introduced an
off-by-one error wasn't caught by any existing test.  Switch the roles
of XA_MARK_1 and XA_MARK_2 to catch that bug.

Reported-by: Cyrill Gorcunov 
Signed-off-by: Matthew Wilcox

sbitmap: Protect swap_lock from softirqs

2019-01-14T19:31:18+00:00

The swap_lock used by sbitmap has a chain with locks taken from softirq,
but the swap_lock is not protected from being preempted by softirqs.

A chain exists of:

 sbq->ws[i].wait -> dispatch_wait_lock -> swap_lock

Where the sbq->ws[i].wait lock can be taken from softirq context, which
means all locks below it in the chain must also be protected from
softirqs.

Reported-by: Clark Williams 
Fixes: 58ab5e32e6fd ("sbitmap: silence bogus lockdep IRQ warning")
Fixes: ea86ea2cdced ("sbitmap: amortize cost of clearing bits")
Cc: Jens Axboe 
Cc: Ming Lei 
Cc: Guenter Roeck 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Linus Torvalds

XArray: Honour reserved entries in xa_insert

2019-01-07T03:12:58+00:00

xa_insert() should treat reserved entries as occupied, not as available.
Also, it should treat requests to insert a NULL pointer as a request
to reserve the slot.  Add xa_insert_bh() and xa_insert_irq() for
completeness.

Signed-off-by: Matthew Wilcox

XArray: Permit storing 2-byte-aligned pointers

2019-01-07T03:12:57+00:00

On m68k, statically allocated pointers may only be two-byte aligned.
This clashes with the XArray's method for tagging internal pointers.
Permit storing these pointers in single slots (ie not in multislots).

Signed-off-by: Matthew Wilcox

XArray: Change xa_for_each iterator

2019-01-07T02:24:43+00:00

There were three problems with this API:
1. It took too many arguments; almost all users wanted to iterate over
every element in the array rather than a subset.
2. It required that 'index' be initialised before use, and there's no
realistic way to make GCC catch that.
3. 'index' and 'entry' were the opposite way round from every other
member of the XArray APIs.

So split it into three different APIs:

xa_for_each(xa, index, entry)
xa_for_each_start(xa, index, entry, start)
xa_for_each_marked(xa, index, entry, filter)

Signed-off-by: Matthew Wilcox

XArray: Turn xa_init_flags into a static inline

2019-01-07T02:24:43+00:00

A regular xa_init_flags() put all dynamically-initialised XArrays into
the same locking class.  That leads to lockdep believing that taking
one XArray lock while holding another is a deadlock.  It's possible to
work around some of these situations with separate locking classes for
irq/bh/regular XArrays, and SINGLE_DEPTH_NESTING, but that's ugly, and
it doesn't work for all situations (where we have completely unrelated
XArrays).

Signed-off-by: Matthew Wilcox