linux-stable.git, branch v5.3.12

Linux 5.3.12

2019-11-20T15:49:17+00:00

slcan: Fix memory leak in error path

2019-11-20T15:49:16+00:00

commit ed50e1600b4483c049ce76e6bd3b665a6a9300ed upstream.

This patch is fixing memory leak reported by Syzkaller:

BUG: memory leak unreferenced object 0xffff888067f65500 (size 4096):
  comm "syz-executor043", pid 454, jiffies 4294759719 (age 11.930s)
  hex dump (first 32 bytes):
    73 6c 63 61 6e 30 00 00 00 00 00 00 00 00 00 00 slcan0..........
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
  backtrace:
    [<00000000a06eec0d>] __kmalloc+0x18b/0x2c0
    [<0000000083306e66>] kvmalloc_node+0x3a/0xc0
    [<000000006ac27f87>] alloc_netdev_mqs+0x17a/0x1080
    [<0000000061a996c9>] slcan_open+0x3ae/0x9a0
    [<000000001226f0f9>] tty_ldisc_open.isra.1+0x76/0xc0
    [<0000000019289631>] tty_set_ldisc+0x28c/0x5f0
    [<000000004de5a617>] tty_ioctl+0x48d/0x1590
    [<00000000daef496f>] do_vfs_ioctl+0x1c7/0x1510
    [<0000000059068dbc>] ksys_ioctl+0x99/0xb0
    [<000000009a6eb334>] __x64_sys_ioctl+0x78/0xb0
    [<0000000053d0332e>] do_syscall_64+0x16f/0x580
    [<0000000021b83b99>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
    [<000000008ea75434>] 0xffffffffffffffff

Cc: Wolfgang Grandegger 
Cc: Marc Kleine-Budde 
Cc: Lukas Bulwahn 
Signed-off-by: Jouni Hogander 
Signed-off-by: Marc Kleine-Budde 
Cc: Oliver Hartkopp 
Signed-off-by: Greg Kroah-Hartman

mmc: sdhci-of-at91: fix quirk2 overwrite

2019-11-20T15:49:16+00:00

commit fed23c5829ecab4ddc712d7b0046e59610ca3ba4 upstream.

The quirks2 are parsed and set (e.g. from DT) before the quirk for broken
HS200 is set in the driver.
The driver needs to enable just this flag, not rewrite the whole quirk set.

Fixes: 7871aa60ae00 ("mmc: sdhci-of-at91: add quirk for broken HS200")
Signed-off-by: Eugen Hristev 
Acked-by: Adrian Hunter 
Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson 
Signed-off-by: Greg Kroah-Hartman

mm/page_io.c: do not free shared swap slots

2019-11-20T15:49:15+00:00

commit 5df373e95689b9519b8557da7c5bd0db0856d776 upstream.

The following race is observed due to which a processes faulting on a
swap entry, finds the page neither in swapcache nor swap.  This causes
zram to give a zero filled page that gets mapped to the process,
resulting in a user space crash later.

Consider parent and child processes Pa and Pb sharing the same swap slot
with swap_count 2.  Swap is on zram with SWP_SYNCHRONOUS_IO set.
Virtual address 'VA' of Pa and Pb points to the shared swap entry.

Pa                                       Pb

fault on VA                              fault on VA
do_swap_page                             do_swap_page
lookup_swap_cache fails                  lookup_swap_cache fails
                                         Pb scheduled out
swapin_readahead (deletes zram entry)
swap_free (makes swap_count 1)
                                         Pb scheduled in
                                         swap_readpage (swap_count == 1)
                                         Takes SWP_SYNCHRONOUS_IO path
                                         zram enrty absent
                                         zram gives a zero filled page

Fix this by making sure that swap slot is freed only when swap count
drops down to one.

Link: http://lkml.kernel.org/r/1571743294-14285-1-git-send-email-vinmenon@codeaurora.org
Fixes: aa8d22a11da9 ("mm: swap: SWP_SYNCHRONOUS_IO: skip swapcache only if swapped page has no other reference")
Signed-off-by: Vinayak Menon 
Suggested-by: Minchan Kim 
Acked-by: Minchan Kim 
Cc: Michal Hocko 
Cc: Hugh Dickins 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

mm/memory_hotplug: fix try_offline_node()

2019-11-20T15:49:15+00:00

commit 2c91f8fc6c999fe10185d8ad99fda1759f662f70 upstream.

try_offline_node() is pretty much broken right now:

 - The node span is updated when onlining memory, not when adding it. We
   ignore memory that was mever onlined. Bad.

 - We touch possible garbage memmaps. The pfn_to_nid(pfn) can easily
   trigger a kernel panic. Bad for memory that is offline but also bad
   for subsection hotadd with ZONE_DEVICE, whereby the memmap of the
   first PFN of a section might contain garbage.

 - Sections belonging to mixed nodes are not properly considered.

As memory blocks might belong to multiple nodes, we would have to walk
all pageblocks (or at least subsections) within present sections.
However, we don't have a way to identify whether a memmap that is not
online was initialized (relevant for ZONE_DEVICE).  This makes things
more complicated.

Luckily, we can piggy pack on the node span and the nid stored in memory
blocks.  Currently, the node span is grown when calling
move_pfn_range_to_zone() - e.g., when onlining memory, and shrunk when
removing memory, before calling try_offline_node().  Sysfs links are
created via link_mem_sections(), e.g., during boot or when adding
memory.

If the node still spans memory or if any memory block belongs to the
nid, we don't set the node offline.  As memory blocks that span multiple
nodes cannot get offlined, the nid stored in memory blocks is reliable
enough (for such online memory blocks, the node still spans the memory).

Introduce for_each_memory_block() to efficiently walk all memory blocks.

Note: We will soon stop shrinking the ZONE_DEVICE zone and the node span
when removing ZONE_DEVICE memory to fix similar issues (access of
garbage memmaps) - until we have a reliable way to identify whether
these memmaps were properly initialized.  This implies later, that once
a node had ZONE_DEVICE memory, we won't be able to set a node offline -
which should be acceptable.

Since commit f1dd2cd13c4b ("mm, memory_hotplug: do not associate
hotadded memory to zones until online") memory that is added is not
assoziated with a zone/node (memmap not initialized).  The introducing
commit 60a5a19e7419 ("memory-hotplug: remove sysfs file of node")
already missed that we could have multiple nodes for a section and that
the zone/node span is updated when onlining pages, not when adding them.

I tested this by hotplugging two DIMMs to a memory-less and cpu-less
NUMA node.  The node is properly onlined when adding the DIMMs.  When
removing the DIMMs, the node is properly offlined.

Masayoshi Mizuma reported:

: Without this patch, memory hotplug fails as panic:
:
:  BUG: kernel NULL pointer dereference, address: 0000000000000000
:  ...
:  Call Trace:
:   remove_memory_block_devices+0x81/0xc0
:   try_remove_memory+0xb4/0x130
:   __remove_memory+0xa/0x20
:   acpi_memory_device_remove+0x84/0x100
:   acpi_bus_trim+0x57/0x90
:   acpi_bus_trim+0x2e/0x90
:   acpi_device_hotplug+0x2b2/0x4d0
:   acpi_hotplug_work_fn+0x1a/0x30
:   process_one_work+0x171/0x380
:   worker_thread+0x49/0x3f0
:   kthread+0xf8/0x130
:   ret_from_fork+0x35/0x40

[david@redhat.com: v3]
  Link: http://lkml.kernel.org/r/20191102120221.7553-1-david@redhat.com
Link: http://lkml.kernel.org/r/20191028105458.28320-1-david@redhat.com
Fixes: 60a5a19e7419 ("memory-hotplug: remove sysfs file of node")
Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") # visiable after d0dc12e86b319
Signed-off-by: David Hildenbrand 
Tested-by: Masayoshi Mizuma 
Cc: Tang Chen 
Cc: Greg Kroah-Hartman 
Cc: "Rafael J. Wysocki" 
Cc: Keith Busch 
Cc: Jiri Olsa 
Cc: "Peter Zijlstra (Intel)" 
Cc: Jani Nikula 
Cc: Nayna Jain 
Cc: Michal Hocko 
Cc: Oscar Salvador 
Cc: Stephen Rothwell 
Cc: Dan Williams 
Cc: Pavel Tatashin 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

mm: slub: really fix slab walking for init_on_free

2019-11-20T15:49:14+00:00

commit aea4df4c53f754cc229edde6c5465e481311cc49 upstream.

Commit 1b7e816fc80e ("mm: slub: Fix slab walking for init_on_free")
fixed one problem with the slab walking but missed a key detail: When
walking the list, the head and tail pointers need to be updated since we
end up reversing the list as a result.  Without doing this, bulk free is
broken.

One way this is exposed is a NULL pointer with slub_debug=F:

  =============================================================================
  BUG skbuff_head_cache (Tainted: G                T): Object already free
  -----------------------------------------------------------------------------

  INFO: Slab 0x000000000d2d2f8f objects=16 used=3 fp=0x0000000064309071 flags=0x3fff00000000201
  BUG: kernel NULL pointer dereference, address: 0000000000000000
  Oops: 0000 [#1] PREEMPT SMP PTI
  RIP: 0010:print_trailer+0x70/0x1d5
  Call Trace:
   
   free_debug_processing.cold.37+0xc9/0x149
   __slab_free+0x22a/0x3d0
   kmem_cache_free_bulk+0x415/0x420
   __kfree_skb_flush+0x30/0x40
   net_rx_action+0x2dd/0x480
   __do_softirq+0xf0/0x246
   irq_exit+0x93/0xb0
   do_IRQ+0xa0/0x110
   common_interrupt+0xf/0xf
   

Given we're now almost identical to the existing debugging code which
correctly walks the list, combine with that.

Link: https://lkml.kernel.org/r/20191104170303.GA50361@gandi.net
Link: http://lkml.kernel.org/r/20191106222208.26815-1-labbott@redhat.com
Fixes: 1b7e816fc80e ("mm: slub: Fix slab walking for init_on_free")
Signed-off-by: Laura Abbott 
Reported-by: Thibaut Sautereau 
Acked-by: David Rientjes 
Tested-by: Alexander Potapenko 
Acked-by: Alexander Potapenko 
Cc: Kees Cook 
Cc: "David S. Miller" 
Cc: Vlastimil Babka 
Cc: 
Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: Joonsoo Kim 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

mm: hugetlb: switch to css_tryget() in hugetlb_cgroup_charge_cgroup()

2019-11-20T15:49:14+00:00

commit 0362f326d86c645b5e96b7dbc3ee515986ed019d upstream.

An exiting task might belong to an offline cgroup.  In this case an
attempt to grab a cgroup reference from the task can end up with an
infinite loop in hugetlb_cgroup_charge_cgroup(), because neither the
cgroup will become online, neither the task will be migrated to a live
cgroup.

Fix this by switching over to css_tryget().  As css_tryget_online()
can't guarantee that the cgroup won't go offline, in most cases the
check doesn't make sense.  In this particular case users of
hugetlb_cgroup_charge_cgroup() are not affected by this change.

A similar problem is described by commit 18fa84a2db0e ("cgroup: Use
css_tryget() instead of css_tryget_online() in task_get_css()").

Link: http://lkml.kernel.org/r/20191106225131.3543616-2-guro@fb.com
Signed-off-by: Roman Gushchin 
Acked-by: Johannes Weiner 
Acked-by: Tejun Heo 
Reviewed-by: Shakeel Butt 
Cc: Michal Hocko 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

mm: memcg: switch to css_tryget() in get_mem_cgroup_from_mm()

2019-11-20T15:49:13+00:00

commit 00d484f354d85845991b40141d40ba9e5eb60faf upstream.

We've encountered a rcu stall in get_mem_cgroup_from_mm():

  rcu: INFO: rcu_sched self-detected stall on CPU
  rcu: 33-....: (21000 ticks this GP) idle=6c6/1/0x4000000000000002 softirq=35441/35441 fqs=5017
  (t=21031 jiffies g=324821 q=95837) NMI backtrace for cpu 33
  <...>
  RIP: 0010:get_mem_cgroup_from_mm+0x2f/0x90
  <...>
   __memcg_kmem_charge+0x55/0x140
   __alloc_pages_nodemask+0x267/0x320
   pipe_write+0x1ad/0x400
   new_sync_write+0x127/0x1c0
   __kernel_write+0x4f/0xf0
   dump_emit+0x91/0xc0
   writenote+0xa0/0xc0
   elf_core_dump+0x11af/0x1430
   do_coredump+0xc65/0xee0
   get_signal+0x132/0x7c0
   do_signal+0x36/0x640
   exit_to_usermode_loop+0x61/0xd0
   do_syscall_64+0xd4/0x100
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

The problem is caused by an exiting task which is associated with an
offline memcg.  We're iterating over and over in the do {} while
(!css_tryget_online()) loop, but obviously the memcg won't become online
and the exiting task won't be migrated to a live memcg.

Let's fix it by switching from css_tryget_online() to css_tryget().

As css_tryget_online() cannot guarantee that the memcg won't go offline,
the check is usually useless, except some rare cases when for example it
determines if something should be presented to a user.

A similar problem is described by commit 18fa84a2db0e ("cgroup: Use
css_tryget() instead of css_tryget_online() in task_get_css()").

Johannes:

: The bug aside, it doesn't matter whether the cgroup is online for the
: callers.  It used to matter when offlining needed to evacuate all charges
: from the memcg, and so needed to prevent new ones from showing up, but we
: don't care now.

Link: http://lkml.kernel.org/r/20191106225131.3543616-1-guro@fb.com
Signed-off-by: Roman Gushchin 
Acked-by: Johannes Weiner 
Acked-by: Tejun Heo 
Reviewed-by: Shakeel Butt 
Cc: Michal Hocko 
Cc: Michal Koutn 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

mm: mempolicy: fix the wrong return value and potential pages leak of mbind

2019-11-20T15:49:13+00:00

commit a85dfc305a21acfc48fa28a0fa0a0cb6ad496120 upstream.

Commit d883544515aa ("mm: mempolicy: make the behavior consistent when
MPOL_MF_MOVE* and MPOL_MF_STRICT were specified") fixed the return value
of mbind() for a couple of corner cases.  But, it altered the errno for
some other cases, for example, mbind() should return -EFAULT when part
or all of the memory range specified by nodemask and maxnode points
outside your accessible address space, or there was an unmapped hole in
the specified memory range specified by addr and len.

Fix this by preserving the errno returned by queue_pages_range().  And,
the pagelist may be not empty even though queue_pages_range() returns
error, put the pages back to LRU since mbind_range() is not called to
really apply the policy so those pages should not be migrated, this is
also the old behavior before the problematic commit.

Link: http://lkml.kernel.org/r/1572454731-3925-1-git-send-email-yang.shi@linux.alibaba.com
Fixes: d883544515aa ("mm: mempolicy: make the behavior consistent when MPOL_MF_MOVE* and MPOL_MF_STRICT were specified")
Signed-off-by: Yang Shi 
Reported-by: Li Xinhai 
Reviewed-by: Li Xinhai 
Cc: Vlastimil Babka 
Cc: Michal Hocko 
Cc: Mel Gorman 
Cc: 	[4.19 and 5.2+]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

iommu/vt-d: Fix QI_DEV_IOTLB_PFSID and QI_DEV_EIOTLB_PFSID macros

2019-11-20T15:49:12+00:00

commit 4e7120d79edb31e4ee68e6f8421448e4603be1e9 upstream.

For both PASID-based-Device-TLB Invalidate Descriptor and
Device-TLB Invalidate Descriptor, the Physical Function Source-ID
value is split according to this layout:

PFSID[3:0] is set at offset 12 and PFSID[15:4] is put at offset 52.
Fix the part laid out at offset 52.

Fixes: 0f725561e1684 ("iommu/vt-d: Add definitions for PFSID")
Signed-off-by: Eric Auger 
Acked-by: Jacob Pan 
Cc: stable@vger.kernel.org # v4.19+
Acked-by: Lu Baolu 
Signed-off-by: Joerg Roedel 
Signed-off-by: Greg Kroah-Hartman