From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Thu, 28 Jan 2021 19:18:43 +0000 (-0800)
Subject: Merge tag 'locking-urgent-2021-01-28' of git://git.kernel.org/pub/scm/linux/kernel... 
X-Git-Tag: accepted/tizen/unified/20230118.172025~7994
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=c64396cc36c6e60704ab06c1fb1c4a46179c9120;p=platform%2Fkernel%2Flinux-rpi.git

Merge tag 'locking-urgent-2021-01-28' of git://git./linux/kernel/git/tip/tip

Pull locking fixes from Thomas Gleixner:
 "A set of PI futex fixes:

   - Address a longstanding issue where the user space part of the PI
     futex is not writeable. The kernel returns with inconsistent state
     which can in the worst case result in a UAF of a tasks kernel
     stack.

     The solution is to establish consistent kernel state which makes
     future operations on the futex fail because user space and kernel
     space state are inconsistent. Not a problem as PI futexes
     fundamentaly require a functional RW mapping and if user space
     pulls the rug under it, then it can keep the pieces it asked for.

   - Address an issue where the return value is incorrect in case that
     the futex was acquired after a timeout/signal made the waiter drop
     out of the rtmutex wait.

     In one of the corner cases the kernel returned an error code
     despite having successfully acquired the futex"

* tag 'locking-urgent-2021-01-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  futex: Handle faults correctly for PI futexes
  futex: Simplify fixup_pi_state_owner()
  futex: Use pi_state_update_owner() in put_pi_state()
  rtmutex: Remove unused argument from rt_mutex_proxy_unlock()
  futex: Provide and use pi_state_update_owner()
  futex: Replace pointless printk in fixup_owner()
  futex: Ensure the correct return value from futex_lock_pi()
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c64396cc36c6e60704ab06c1fb1c4a46179c9120