linux-toradex.git/lib, branch v4.5-rc4

Merge tag 'driver-core-4.5-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2016-02-14T20:34:53+00:00

Pull driver core fix from Greg KH:
 "Here is one driver core, well klist, fix for 4.5-rc4.

  It fixes a problem found in the scsi device list traversal that
  probably also could be triggered by other subsystems.

  The fix has been in linux-next for a while with no reported problems"

* tag 'driver-core-4.5-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  klist: fix starting point removed bug in klist iterators

vsprintf: kptr_restrict is okay in IRQ when 2

2016-02-12T02:35:48+00:00

The kptr_restrict flag, when set to 1, only prints the kernel address
when the user has CAP_SYSLOG.  When it is set to 2, the kernel address
is always printed as zero.  When set to 1, this needs to check whether
or not we're in IRQ.

However, when set to 2, this check is unneccessary, and produces
confusing results in dmesg.  Thus, only make sure we're not in IRQ when
mode 1 is used, but not mode 2.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Jason A. Donenfeld 
Cc: Rasmus Villemoes 
Cc: Kees Cook 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ubsan: cosmetic fix to Kconfig text

2016-02-12T02:35:48+00:00

When enabling UBSAN_SANITIZE_ALL, the kernel image size gets increased
significantly (~3x).  So, it sounds better to have some note in Kconfig.

And, fixed a typo.

Signed-off-by: Yang Shi 
Acked-by: Andrey Ryabinin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'for-4.5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

2016-02-10T19:04:05+00:00

Pull workqueue fixes from Tejun Heo:
 "Workqueue fixes for v4.5-rc3.

   - Remove a spurious triggering of flush dependency warning.

   - Officially break local execution guarantee of unbound work items
     and add a debug feature to flush out usages which depend on it.

   - Work around CPU -> NODE mapping becoming invalid on CPU offline.

  The branch is young but pushing out early as stable kernels are being
  affected"

* 'for-4.5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: handle NUMA_NO_NODE for unbound pool_workqueue lookup
  workqueue: implement "workqueue.debug_force_rr_cpu" debug feature
  workqueue: schedule WORK_CPU_UNBOUND work on wq_unbound_cpumask CPUs
  Revert "workqueue: make sure delayed work run in local cpu"
  workqueue: skip flush dependency checks for legacy workqueues

workqueue: implement "workqueue.debug_force_rr_cpu" debug feature

2016-02-09T22:59:38+00:00

Workqueue used to guarantee local execution for work items queued
without explicit target CPU.  The guarantee is gone now which can
break some usages in subtle ways.  To flush out those cases, this
patch implements a debug feature which forces round-robin CPU
selection for all such work items.

The debug feature defaults to off and can be enabled with a kernel
parameter.  The default can be flipped with a debug config option.

If you hit this commit during bisection, please refer to 041bd12e272c
("Revert "workqueue: make sure delayed work run in local cpu"") for
more information and ping me.

Signed-off-by: Tejun Heo

scatterlist: fix a typo in comment block of sg_miter_stop()

2016-02-08T18:15:17+00:00

Fix the doubled "started" and tidy up the following sentences.

Signed-off-by: Masahiro Yamada 
Signed-off-by: Linus Torvalds

klist: fix starting point removed bug in klist iterators

2016-02-08T06:18:47+00:00

The starting node for a klist iteration is often passed in from
somewhere way above the klist infrastructure, meaning there's no
guarantee the node is still on the list.  We've seen this in SCSI where
we use bus_find_device() to iterate through a list of devices.  In the
face of heavy hotplug activity, the last device returned by
bus_find_device() can be removed before the next call.  This leads to

Dec  3 13:22:02 localhost kernel: WARNING: CPU: 2 PID: 28073 at include/linux/kref.h:47 klist_iter_init_node+0x3d/0x50()
Dec  3 13:22:02 localhost kernel: Modules linked in: scsi_debug x86_pkg_temp_thermal kvm_intel kvm irqbypass crc32c_intel joydev iTCO_wdt dcdbas ipmi_devintf acpi_power_meter iTCO_vendor_support ipmi_si imsghandler pcspkr wmi acpi_cpufreq tpm_tis tpm shpchp lpc_ich mfd_core nfsd nfs_acl lockd grace sunrpc tg3 ptp pps_core
Dec  3 13:22:02 localhost kernel: CPU: 2 PID: 28073 Comm: cat Not tainted 4.4.0-rc1+ #2
Dec  3 13:22:02 localhost kernel: Hardware name: Dell Inc. PowerEdge R320/08VT7V, BIOS 2.0.22 11/19/2013
Dec  3 13:22:02 localhost kernel: ffffffff81a20e77 ffff880613acfd18 ffffffff81321eef 0000000000000000
Dec  3 13:22:02 localhost kernel: ffff880613acfd50 ffffffff8107ca52 ffff88061176b198 0000000000000000
Dec  3 13:22:02 localhost kernel: ffffffff814542b0 ffff880610cfb100 ffff88061176b198 ffff880613acfd60
Dec  3 13:22:02 localhost kernel: Call Trace:
Dec  3 13:22:02 localhost kernel: [] dump_stack+0x44/0x55
Dec  3 13:22:02 localhost kernel: [] warn_slowpath_common+0x82/0xc0
Dec  3 13:22:02 localhost kernel: [] ? proc_scsi_show+0x20/0x20
Dec  3 13:22:02 localhost kernel: [] warn_slowpath_null+0x1a/0x20
Dec  3 13:22:02 localhost kernel: [] klist_iter_init_node+0x3d/0x50
Dec  3 13:22:02 localhost kernel: [] bus_find_device+0x51/0xb0
Dec  3 13:22:02 localhost kernel: [] scsi_seq_next+0x2d/0x40
[...]

And an eventual crash. It can actually occur in any hotplug system
which has a device finder and a starting device.

We can fix this globally by making sure the starting node for
klist_iter_init_node() is actually a member of the list before using it
(and by starting from the beginning if it isn't).

Reported-by: Ewan D. Milne 
Tested-by: Ewan D. Milne 
Cc: stable@vger.kernel.org
Signed-off-by: James Bottomley 
Signed-off-by: Greg Kroah-Hartman

dump_stack: avoid potential deadlocks

2016-02-06T02:10:40+00:00

Some servers experienced fatal deadlocks because of a combination of
bugs, leading to multiple cpus calling dump_stack().

The checksumming bug was fixed in commit 34ae6a1aa054 ("ipv6: update
skb->csum when CE mark is propagated").

The second problem is a faulty locking in dump_stack()

CPU1 runs in process context and calls dump_stack(), grabs dump_lock.

   CPU2 receives a TCP packet under softirq, grabs socket spinlock, and
   call dump_stack() from netdev_rx_csum_fault().

   dump_stack() spins on atomic_cmpxchg(&dump_lock, -1, 2), since
   dump_lock is owned by CPU1

While dumping its stack, CPU1 is interrupted by a softirq, and happens
to process a packet for the TCP socket locked by CPU2.

CPU1 spins forever in spin_lock() : deadlock

Stack trace on CPU1 looked like :

    NMI backtrace for cpu 1
    RIP: _raw_spin_lock+0x25/0x30
    ...
    Call Trace:
      
      tcp_v6_rcv+0x243/0x620
      ip6_input_finish+0x11f/0x330
      ip6_input+0x38/0x40
      ip6_rcv_finish+0x3c/0x90
      ipv6_rcv+0x2a9/0x500
      process_backlog+0x461/0xaa0
      net_rx_action+0x147/0x430
      __do_softirq+0x167/0x2d0
      call_softirq+0x1c/0x30
      do_softirq+0x3f/0x80
      irq_exit+0x6e/0xc0
      smp_call_function_single_interrupt+0x35/0x40
      call_function_single_interrupt+0x6a/0x70
      
      printk+0x4d/0x4f
      printk_address+0x31/0x33
      print_trace_address+0x33/0x3c
      print_context_stack+0x7f/0x119
      dump_trace+0x26b/0x28e
      show_trace_log_lvl+0x4f/0x5c
      show_stack_log_lvl+0x104/0x113
      show_stack+0x42/0x44
      dump_stack+0x46/0x58
      netdev_rx_csum_fault+0x38/0x3c
      __skb_checksum_complete_head+0x6e/0x80
      __skb_checksum_complete+0x11/0x20
      tcp_rcv_established+0x2bd5/0x2fd0
      tcp_v6_do_rcv+0x13c/0x620
      sk_backlog_rcv+0x15/0x30
      release_sock+0xd2/0x150
      tcp_recvmsg+0x1c1/0xfc0
      inet_recvmsg+0x7d/0x90
      sock_recvmsg+0xaf/0xe0
      ___sys_recvmsg+0x111/0x3b0
      SyS_recvmsg+0x5c/0xb0
      system_call_fastpath+0x16/0x1b

Fixes: b58d977432c8 ("dump_stack: serialize the output from dump_stack()")
Signed-off-by: Eric Dumazet 
Cc: Alex Thorlton 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

radix-tree: fix race in gang lookup

2016-02-03T16:28:43+00:00

If the indirect_ptr bit is set on a slot, that indicates we need to redo
the lookup.  Introduce a new function radix_tree_iter_retry() which
forces the loop to retry the lookup by setting 'slot' to NULL and
turning the iterator back to point at the problematic entry.

This is a pretty rare problem to hit at the moment; the lookup has to
race with a grow of the radix tree from a height of 0.  The consequences
of hitting this race are that gang lookup could return a pointer to a
radix_tree_node instead of a pointer to whatever the user had inserted
in the tree.

Fixes: cebbd29e1c2f ("radix-tree: rewrite gang lookup using iterator")
Signed-off-by: Matthew Wilcox 
Cc: Hugh Dickins 
Cc: Ohad Ben-Cohen 
Cc: Konstantin Khlebnikov 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lib/test-string_helpers.c: fix and improve string_get_size() tests

2016-02-03T16:28:43+00:00

Recently added commit 564b026fbd0d ("string_helpers: fix precision loss
for some inputs") fixed precision issues for string_get_size() and broke
tests.

Fix and improve them: test both STRING_UNITS_2 and STRING_UNITS_10 at a
time, better failure reporting, test small an huge values.

Fixes: 564b026fbd0d28e9 ("string_helpers: fix precision loss for some inputs")
Signed-off-by: Vitaly Kuznetsov 
Cc: Andy Shevchenko 
Cc: Rasmus Villemoes 
Cc: James Bottomley 
Cc: James Bottomley 
Cc: "James E.J. Bottomley" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds