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Ben Wolsieffer 90b263db85 futex: Don't include process MM in futex key on no-MMU
[ Upstream commit c73801ae4f ]

On no-MMU, all futexes are treated as private because there is no need
to map a virtual address to physical to match the futex across
processes. This doesn't quite work though, because private futexes
include the current process's mm_struct as part of their key. This makes
it impossible for one process to wake up a shared futex being waited on
in another process.

Fix this bug by excluding the mm_struct from the key. With
a single address space, the futex address is already a unique key.

Fixes: 784bdf3bb6 ("futex: Assume all mappings are private on !MMU systems")
Signed-off-by: Ben Wolsieffer <ben.wolsieffer@hefring.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: André Almeida <andrealmeid@igalia.com>
Link: https://lore.kernel.org/r/20231019204548.1236437-2-ben.wolsieffer@hefring.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-20 11:08:13 +01:00
Documentation Documentation: sysctl: align cells in second content column 2023-10-25 11:58:54 +02:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
arch x86/srso: Fix SBPB enablement for (possible) future fixed HW 2023-11-20 11:08:13 +01:00
block block: fix use-after-free of q->q_usage_counter 2023-10-10 21:59:05 +02:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:22:01 +02:00
crypto crypto: lrw,xts - Replace strlcpy with strscpy 2023-09-23 11:09:55 +02:00
drivers misc: pci_endpoint_test: Add deviceID for J721S2 PCIe EP device support 2023-11-08 17:26:51 +01:00
fs writeback, cgroup: switch inodes with dirty timestamps to release dying cgwbs 2023-11-20 11:08:13 +01:00
include PCI: Prevent xHCI driver from claiming AMD VanGogh USB3 DRD device 2023-11-08 17:26:49 +01:00
init x86/mm: Initialize text poking earlier 2023-08-08 19:58:33 +02:00
io_uring io_uring/fs: remove sqe->rw_flags checking from LINKAT 2023-10-06 13:18:22 +02:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:28:45 +01:00
kernel futex: Don't include process MM in futex key on no-MMU 2023-11-20 11:08:13 +01:00
lib lib/Kconfig.debug: do not enable DEBUG_PREEMPT by default 2023-10-25 11:58:54 +02:00
mm vfs: fix readahead(2) on block devices 2023-11-20 11:08:13 +01:00
net can: isotp: isotp_sendmsg(): fix TX state detection and wait behavior 2023-11-08 17:26:49 +01:00
samples samples/hw_breakpoint: fix building without module unloading 2023-09-23 11:10:01 +02:00
scripts modpost: add missing else to the "of" check 2023-10-10 21:59:07 +02:00
security KEYS: trusted: Remove redundant static calls usage 2023-10-19 23:05:33 +02:00
sound ALSA: hda: intel-dsp-config: Fix JSL Chromebook quirk detection 2023-11-08 17:26:51 +01:00
tools objtool/x86: add missing embedded_insn check 2023-11-08 17:26:43 +01:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:27:15 +01:00
virt KVM: Grab a reference to KVM for VM and vCPU stats file descriptors 2023-08-03 10:22:40 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS iio: stx104: Move to addac subdirectory 2023-08-26 14:23:27 +02:00
Makefile Linux 5.15.138 2023-11-08 17:26:52 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.