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  9. 03 Feb, 2016 5 commits
    • Ioan-Adrian Ratiu's avatar
      HID: usbhid: fix recursive deadlock · 9e9d8b71
      Ioan-Adrian Ratiu authored 
      commit e470127e upstream.

The critical section protected by usbhid->lock in hid_ctrl() is too
big and because of this it causes a recursive deadlock. "Too big" means
the case statement and the call to hid_input_report() do not need to be
protected by the spinlock (no URB operations are done inside them).

The deadlock happens because in certain rare cases drivers try to grab
the lock while handling the ctrl irq which grabs the lock before them
as described above. For example newer wacom tablets like 056a:033c try
to reschedule proximity reads from wacom_intuos_schedule_prox_event()
calling hid_hw_request() -> usbhid_request() -> usbhid_submit_report()
which tries to grab the usbhid lock already held by hid_ctrl().

There are two ways to get out of this deadlock:
    1. Make the drivers work "around" the ctrl critical region, in the
    wacom case for ex. by delaying the scheduling of the proximity read
    request itself to a workqueue.
    2. Shrink the critical region so the usbhid lock protects only the
    instructions which modify usbhid state, calling hid_input_report()
    with the spinlock unlocked, allowing the device driver to grab the
    lock first, finish and then grab the lock afterwards in hid_ctrl().

This patch implements the 2nd solution.
Signed-off-by: default avatarIoan-Adrian Ratiu <adi@adirat.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
Cc: Jason Gerecke <killertofu@gmail.com>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      9e9d8b71
    • Jamie Bainbridge's avatar
      cifs: Ratelimit kernel log messages · 1acdf404
      Jamie Bainbridge authored 
      commit ec7147a9 upstream.

Under some conditions, CIFS can repeatedly call the cifs_dbg() logging
wrapper. If done rapidly enough, the console framebuffer can softlockup
or "rcu_sched self-detected stall". Apply the built-in log ratelimiters
to prevent such hangs.
Signed-off-by: default avatarJamie Bainbridge <jamie.bainbridge@gmail.com>
Signed-off-by: default avatarSteve French <smfrench@gmail.com>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      1acdf404
    • Andrew Morton's avatar
      openrisc: fix CONFIG_UID16 setting · cc8e8d92
      Andrew Morton authored 
      commit 04ea1e91 upstream.

openrisc-allnoconfig:

  kernel/uid16.c: In function 'SYSC_setgroups16':
  kernel/uid16.c:184:2: error: implicit declaration of function 'groups_alloc'
  kernel/uid16.c:184:13: warning: assignment makes pointer from integer without a cast

openrisc shouldn't be setting CONFIG_UID16 when CONFIG_MULTIUSER=n.

Fixes: 2813893f ("kernel: conditionally support non-root users, groups and capabilities")
Reported-by: default avatarFengguang Wu <fengguang.wu@gmail.com>
Cc: Iulia Manda <iulia.manda21@gmail.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      cc8e8d92
    • Guenter Roeck's avatar
      mn10300: Select CONFIG_HAVE_UID16 to fix build failure · 456f6f44
      Guenter Roeck authored 
      commit c86576ea upstream.

mn10300 builds fail with

fs/stat.c: In function 'cp_old_stat':
fs/stat.c:163:2: error: 'old_uid_t' undeclared

ipc/util.c: In function 'ipc64_perm_to_ipc_perm':
ipc/util.c:540:2: error: 'old_uid_t' undeclared

Select CONFIG_HAVE_UID16 and remove local definition of CONFIG_UID16
to fix the problem.

Fixes: fbc416ff ("arm64: fix building without CONFIG_UID16")
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
Acked-by: default avatarAcked-by: David Howells <dhowells@redhat.com>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      456f6f44
    • Arnd Bergmann's avatar
      arm64: fix building without CONFIG_UID16 · 3f457043
      Arnd Bergmann authored 
      commit fbc416ff upstream.

As reported by Michal Simek, building an ARM64 kernel with CONFIG_UID16
disabled currently fails because the system call table still needs to
reference the individual function entry points that are provided by
kernel/sys_ni.c in this case, and the declarations are hidden inside
of #ifdef CONFIG_UID16:

arch/arm64/include/asm/unistd32.h:57:8: error: 'sys_lchown16' undeclared here (not in a function)
 __SYSCALL(__NR_lchown, sys_lchown16)

I believe this problem only exists on ARM64, because older architectures
tend to not need declarations when their system call table is built
in assembly code, while newer architectures tend to not need UID16
support. ARM64 only uses these system calls for compatibility with
32-bit ARM binaries.

This changes the CONFIG_UID16 check into CONFIG_HAVE_UID16, which is
set unconditionally on ARM64 with CONFIG_COMPAT, so we see the
declarations whenever we need them, but otherwise the behavior is
unchanged.

Fixes: af1839eb ("Kconfig: clean up the long arch list for the UID16 config option")
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Acked-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      3f457043
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