linux-stable.git/include, branch v4.4.218

locking/atomic, kref: Add kref_read()

2020-04-02T17:02:39+00:00

commit 2c935bc57221cc2edc787c72ea0e2d30cdcd3d5e upstream.

Since we need to change the implementation, stop exposing internals.

Provide kref_read() to read the current reference count; typically
used for debug messages.

Kills two anti-patterns:

	atomic_read(&kref->refcount)
	kref->refcount.counter

Signed-off-by: Peter Zijlstra (Intel) 
Cc: Andrew Morton 
Cc: Greg Kroah-Hartman 
Cc: Linus Torvalds 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar 
[only add kref_read() to kref.h for stable backports - gregkh]
Signed-off-by: Greg Kroah-Hartman

vt: switch vt_dont_switch to bool

2020-04-02T17:02:39+00:00

commit f400991bf872debffb01c46da882dc97d7e3248e upstream.

vt_dont_switch is pure boolean, no need for whole char.

Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20200219073951.16151-6-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman

vt: selection, introduce vc_is_sel

2020-04-02T17:02:39+00:00

commit dce05aa6eec977f1472abed95ccd71276b9a3864 upstream.

Avoid global variables (namely sel_cons) by introducing vc_is_sel. It
checks whether the parameter is the current selection console. This will
help putting sel_cons to a struct later.

Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20200219073951.16151-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman

uapi glibc compat: fix outer guard of net device flags enum

2020-04-02T17:02:34+00:00

[ Upstream commit efc45154828ae4e49c6b46f59882bfef32697d44 ]

Fix a wrong condition preventing the higher net device flags
IFF_LOWER_UP etc to be defined if net/if.h is included before
linux/if.h.

The comment makes it clear the intention was to allow partial
definition with either parts.

This fixes compilation of userspace programs trying to use
IFF_LOWER_UP, IFF_DORMANT or IFF_ECHO.

Fixes: 4a91cb61bb99 ("uapi glibc compat: fix compile errors when glibc net/if.h included before linux/if.h")
Signed-off-by: Jonas Gorski 
Reviewed-by: Mikko Rapeli 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

futex: Fix inode life-time issue

2020-04-02T17:02:31+00:00

commit 8019ad13ef7f64be44d4f892af9c840179009254 upstream.

As reported by Jann, ihold() does not in fact guarantee inode
persistence. And instead of making it so, replace the usage of inode
pointers with a per boot, machine wide, unique inode identifier.

This sequence number is global, but shared (file backed) futexes are
rare enough that this should not become a performance issue.

Reported-by: Jann Horn 
Suggested-by: Linus Torvalds 
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Greg Kroah-Hartman

x86/mm: split vmalloc_sync_all()

2020-04-02T17:02:31+00:00

commit 763802b53a427ed3cbd419dbba255c414fdd9e7c upstream.

Commit 3f8fd02b1bf1 ("mm/vmalloc: Sync unmappings in
__purge_vmap_area_lazy()") introduced a call to vmalloc_sync_all() in
the vunmap() code-path.  While this change was necessary to maintain
correctness on x86-32-pae kernels, it also adds additional cycles for
architectures that don't need it.

Specifically on x86-64 with CONFIG_VMAP_STACK=y some people reported
severe performance regressions in micro-benchmarks because it now also
calls the x86-64 implementation of vmalloc_sync_all() on vunmap().  But
the vmalloc_sync_all() implementation on x86-64 is only needed for newly
created mappings.

To avoid the unnecessary work on x86-64 and to gain the performance
back, split up vmalloc_sync_all() into two functions:

	* vmalloc_sync_mappings(), and
	* vmalloc_sync_unmappings()

Most call-sites to vmalloc_sync_all() only care about new mappings being
synchronized.  The only exception is the new call-site added in the
above mentioned commit.

Shile Zhang directed us to a report of an 80% regression in reaim
throughput.

Fixes: 3f8fd02b1bf1 ("mm/vmalloc: Sync unmappings in __purge_vmap_area_lazy()")
Reported-by: kernel test robot 
Reported-by: Shile Zhang 
Signed-off-by: Joerg Roedel 
Signed-off-by: Andrew Morton 
Tested-by: Borislav Petkov 
Acked-by: Rafael J. Wysocki 	[GHES]
Cc: Dave Hansen 
Cc: Andy Lutomirski 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: 
Link: http://lkml.kernel.org/r/20191009124418.8286-1-joro@8bytes.org
Link: https://lists.01.org/hyperkitty/list/lkp@lists.01.org/thread/4D3JPPHBNOSPFK2KEPC6KGKS6J25AIDB/
Link: http://lkml.kernel.org/r/20191113095530.228959-1-shile.zhang@linux.alibaba.com
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

fib: add missing attribute validation for tun_id

2020-03-20T08:06:19+00:00

[ Upstream commit 4c16d64ea04056f1b1b324ab6916019f6a064114 ]

Add missing netlink policy entry for FRA_TUN_ID.

Fixes: e7030878fc84 ("fib: Add fib rule match on tunnel id")
Signed-off-by: Jakub Kicinski 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

fs: prevent page refcount overflow in pipe_buf_get

2020-03-11T06:51:15+00:00

commit 15fab63e1e57be9fdb5eec1bbc5916e9825e9acb upstream.

Change pipe_buf_get() to return a bool indicating whether it succeeded
in raising the refcount of the page (if the thing in the pipe is a page).
This removes another mechanism for overflowing the page refcount.  All
callers converted to handle a failure.

Reported-by: Jann Horn 
Signed-off-by: Matthew Wilcox 
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds 
[ 4.4.y backport notes:
  Regarding the change in generic_pipe_buf_get(), note that
  page_cache_get() is the same as get_page(). See mainline commit
  09cbfeaf1a5a6 "mm, fs: get rid of PAGE_CACHE_* and
  page_cache_{get,release} macros" for context. ]
Signed-off-by: Ajay Kaher 
Signed-off-by: Vlastimil Babka 
Signed-off-by: Greg Kroah-Hartman

pipe: add pipe_buf_get() helper

2020-03-11T06:51:15+00:00

commit 7bf2d1df80822ec056363627e2014990f068f7aa upstream.

Signed-off-by: Miklos Szeredi 
Signed-off-by: Al Viro 
Signed-off-by: Ajay Kaher 
Signed-off-by: Vlastimil Babka 
Signed-off-by: Greg Kroah-Hartman

mm: prevent get_user_pages() from overflowing page refcount

2020-03-11T06:51:15+00:00

commit 8fde12ca79aff9b5ba951fce1a2641901b8d8e64 upstream.

If the page refcount wraps around past zero, it will be freed while
there are still four billion references to it.  One of the possible
avenues for an attacker to try to make this happen is by doing direct IO
on a page multiple times.  This patch makes get_user_pages() refuse to
take a new page reference if there are already more than two billion
references to the page.

Reported-by: Jann Horn 
Acked-by: Matthew Wilcox 
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds 
[ 4.4.y backport notes:
  Ajay:     - Added local variable 'err' with-in follow_hugetlb_page()
              from 2be7cfed995e, to resolve compilation error
            - Added page_ref_count()
            - Added missing refcount overflow checks on x86 and s390
              (Vlastimil, thanks for this change)
  Srivatsa: - Replaced call to get_page_foll() with try_get_page_foll() ]
Signed-off-by: Srivatsa S. Bhat (VMware) 
Signed-off-by: Ajay Kaher 
Signed-off-by: Vlastimil Babka 
Signed-off-by: Greg Kroah-Hartman